diff options
Diffstat (limited to 'libjava/classpath/gnu/xml/pipeline/ValidationConsumer.java')
| -rw-r--r-- | libjava/classpath/gnu/xml/pipeline/ValidationConsumer.java | 1928 |
1 files changed, 1928 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/xml/pipeline/ValidationConsumer.java b/libjava/classpath/gnu/xml/pipeline/ValidationConsumer.java new file mode 100644 index 000000000..0346984d3 --- /dev/null +++ b/libjava/classpath/gnu/xml/pipeline/ValidationConsumer.java @@ -0,0 +1,1928 @@ +/* ValidationConsumer.java -- + Copyright (C) 1999,2000,2001 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.xml.pipeline; + +import java.io.IOException; +import java.io.StringReader; +import java.io.StringWriter; +import java.util.EmptyStackException; +import java.util.Enumeration; +import java.util.Hashtable; +import java.util.Stack; +import java.util.StringTokenizer; +import java.util.Vector; + +import org.xml.sax.Attributes; +import org.xml.sax.EntityResolver; +import org.xml.sax.ErrorHandler; +import org.xml.sax.InputSource; +import org.xml.sax.Locator; +import org.xml.sax.SAXException; +import org.xml.sax.SAXParseException; +import org.xml.sax.XMLReader; +import org.xml.sax.helpers.XMLReaderFactory; + +/** + * This class checks SAX2 events to report validity errors; it works as + * both a filter and a terminus on an event pipeline. It relies on the + * producer of SAX events to: </p> <ol> + * + * <li> Conform to the specification of a non-validating XML parser that + * reads all external entities, reported using SAX2 events. </li> + * + * <li> Report ignorable whitespace as such (through the ContentHandler + * interface). This is, strictly speaking, optional for nonvalidating + * XML processors. </li> + * + * <li> Make SAX2 DeclHandler callbacks, with default + * attribute values already normalized (and without "<").</li> + * + * <li> Make SAX2 LexicalHandler startDTD() and endDTD () + * callbacks. </li> + * + * <li> Act as if the <em>(URI)/namespace-prefixes</em> property were + * set to true, by providing XML 1.0 names and all <code>xmlns*</code> + * attributes (rather than omitting either or both). </li> + * + * </ol> + * + * <p> At this writing, the major SAX2 parsers (such as Ælfred2, + * Crimson, and Xerces) meet these requirements, and this validation + * module is used by the optional Ælfred2 validation support. + * </p> + * + * <p> Note that because this is a layered validator, it has to duplicate some + * work that the parser is doing; there are also other cost to layering. + * However, <em>because of layering it doesn't need a parser</em> in order + * to work! You can use it with anything that generates SAX events, such + * as an application component that wants to detect invalid content in + * a changed area without validating an entire document, or which wants to + * ensure that it doesn't write invalid data to a communications partner.</p> + * + * <p> Also, note that because this is a layered validator, the line numbers + * reported for some errors may seem strange. For example, if an element does + * not permit character content, the validator + * will use the locator provided to it. + * That might reflect the last character of a <em>characters</em> event + * callback, rather than the first non-whitespace character. </p> + * + * <hr /> + * + * <!-- + * <p> Of interest is the fact that unlike most currently known XML validators, + * this one can report some cases of non-determinism in element content models. + * It is a compile-time option, enabled by default. This will only report + * such XML errors if they relate to content actually appearing in a document; + * content models aren't aggressively scanned for non-deterministic structure. + * Documents which trigger such non-deterministic transitions may be handled + * differently by different validating parsers, without losing conformance + * to the XML specification. </p> + * --> + * + * <p> Current limitations of the validation performed are in roughly three + * categories. </p> + * + * <p> The first category represents constraints which demand violations + * of software layering: exposing lexical details, one of the first things + * that <em>application</em> programming interfaces (APIs) hide. These + * invariably relate to XML entity handling, and to historical oddities + * of the XML validation semantics. Curiously, + * recent (Autumn 1999) conformance testing showed that these constraints are + * among those handled worst by existing XML validating parsers. Arguments + * have been made that each of these VCs should be turned into WFCs (most + * of them) or discarded (popular for the standalone declaration); in short, + * that these are bugs in the XML specification (not all via SGML): </p><ul> + * + * <li> The <em>Proper Declaration/PE Nesting</em> and + * <em>Proper Group/PE Nesting</em> VCs can't be tested because they + * require access to particularly low level lexical level information. + * In essence, the reason XML isn't a simple thing to parse is that + * it's not a context free grammar, and these constraints elevate that + * SGML-derived context sensitivity to the level of a semantic rule. + * + * <li> The <em>Standalone Document Declaration</em> VC can't be + * tested. This is for two reasons. First, this flag isn't made + * available through SAX2. Second, it also requires breaking that + * lexical layering boundary. (If you ever wondered why classes + * in compiler construction or language design barely mention the + * existence of context-sensitive grammars, it's because of messy + * issues like these.) + * + * <li> The <em>Entity Declared</em> VC can't be tested, because it + * also requires breaking that lexical layering boundary! There's also + * another issue: the VC wording (and seemingly intent) is ambiguous. + * (This is still true in the "Second edition" XML spec.) + * Since there is a WFC of the same name, everyone's life would be + * easier if references to undeclared parsed entities were always well + * formedness errors, regardless of whether they're parameter entities + * or not. (Note that nonvalidating parsers are not required + * to report all such well formedness errors if they don't read external + * parameter entities, although currently most XML parsers read them + * in an attempt to avoid problems from inconsistent parser behavior.) + * + * </ul> + * + * <p> The second category of limitations on this validation represent + * constraints associated with information that is not guaranteed to be + * available (or in one case, <em>is guaranteed not to be available</em>, + * through the SAX2 API: </p><ul> + * + * <li> The <em>Unique Element Type Declaration</em> VC may not be + * reportable, if the underlying parser happens not to expose + * multiple declarations. (Ælfred2 reports these validity + * errors directly.)</li> + * + * <li> Similarly, the <em>Unique Notation Name</em> VC, added in the + * 14-January-2000 XML spec errata to restrict typing models used by + * elements, may not be reportable. (Ælfred reports these + * validity errors directly.) </li> + * + * </ul> + * + * <p> A third category relates to ease of implementation. (Think of this + * as "bugs".) The most notable issue here is character handling. Rather + * than attempting to implement the voluminous character tables in the XML + * specification (Appendix B), Unicode rules are used directly from + * the java.lang.Character class. Recent JVMs have begun to diverge from + * the original specification for that class (Unicode 2.0), meaning that + * different JVMs may handle that aspect of conformance differently. + * </p> + * + * <p> Note that for some of the validity errors that SAX2 does not + * expose, a nonvalidating parser is permitted (by the XML specification) + * to report validity errors. When used with a parser that does so for + * the validity constraints mentioned above (or any other SAX2 event + * stream producer that does the same thing), overall conformance is + * substantially improved. + * + * @see gnu.xml.aelfred2.SAXDriver + * @see gnu.xml.aelfred2.XmlReader + * + * @author David Brownell + */ +public final class ValidationConsumer extends EventFilter +{ + // report error if we happen to notice a non-deterministic choice? + // we won't report buggy content models; just buggy instances + private static final boolean warnNonDeterministic = false; + + // for tracking active content models + private String rootName; + private Stack contentStack = new Stack (); + + // flags for "saved DTD" processing + private boolean disableDeclarations; + private boolean disableReset; + + // + // most VCs get tested when we see element start tags. the per-element + // info (including attributes) recorded here duplicates that found inside + // many nonvalidating parsers, hence dual lookups etc ... that's why a + // layered validator isn't going to be as fast as a non-layered one. + // + + // key = element name; value = ElementInfo + private Hashtable elements = new Hashtable (); + + // some VCs relate to ID/IDREF/IDREFS attributes + // key = id; value = boolean true (defd) or false (refd) + private Hashtable ids = new Hashtable (); + + // we just record declared notation and unparsed entity names. + // the implementation here is simple/slow; these features + // are seldom used, one hopes they'll wither away soon + private Vector notations = new Vector (5, 5); + private Vector nDeferred = new Vector (5, 5); + private Vector unparsed = new Vector (5, 5); + private Vector uDeferred = new Vector (5, 5); + + // note: DocBk 3.1.7 XML defines over 2 dozen notations, + // used when defining unparsed entities for graphics + // (and maybe in other places) + + + + /** + * Creates a pipeline terminus which consumes all events passed to + * it; this will report validity errors as if they were fatal errors, + * unless an error handler is assigned. + * + * @see #setErrorHandler + */ + // constructor used by PipelineFactory + // ... and want one taking system ID of an external subset + public ValidationConsumer () + { + this (null); + } + + /** + * Creates a pipeline filter which reports validity errors and then + * passes events on to the next consumer if they were not fatal. + * + * @see #setErrorHandler + */ + // constructor used by PipelineFactory + // ... and want one taking system ID of an external subset + // (which won't send declaration events) + public ValidationConsumer (EventConsumer next) + { + super (next); + + setContentHandler (this); + setDTDHandler (this); + try { setProperty (DECL_HANDLER, this); } + catch (Exception e) { /* "can't happen" */ } + try { setProperty (LEXICAL_HANDLER, this); } + catch (Exception e) { /* "can't happen" */ } + } + + + private static final String fakeRootName + = ":Nobody:in:their_Right.Mind_would:use:this-name:1x:"; + + /** + * Creates a validation consumer which is preloaded with the DTD provided. + * It does this by constructing a document with that DTD, then parsing + * that document and recording its DTD declarations. Then it arranges + * not to modify that information. + * + * <p> The resulting validation consumer will only validate against + * the specified DTD, regardless of whether some other DTD is found + * in a document being parsed. + * + * @param rootName The name of the required root element; if this is + * null, any root element name will be accepted. + * @param publicId If non-null and there is a non-null systemId, this + * identifier provides an alternate access identifier for the DTD's + * external subset. + * @param systemId If non-null, this is a URI (normally URL) that + * may be used to access the DTD's external subset. + * @param internalSubset If non-null, holds literal markup declarations + * comprising the DTD's internal subset. + * @param resolver If non-null, this will be provided to the parser for + * use when resolving parameter entities (including any external subset). + * @param resolver If non-null, this will be provided to the parser for + * use when resolving parameter entities (including any external subset). + * @param minimalElement If non-null, a minimal valid document. + * + * @exception SAXNotSupportedException If the default SAX parser does + * not support the standard lexical or declaration handlers. + * @exception SAXParseException If the specified DTD has either + * well-formedness or validity errors + * @exception IOException If the specified DTD can't be read for + * some reason + */ + public ValidationConsumer ( + String rootName, + String publicId, + String systemId, + String internalSubset, + EntityResolver resolver, + String minimalDocument + ) throws SAXException, IOException + { + this (null); + + disableReset = true; + if (rootName == null) + rootName = fakeRootName; + + // + // Synthesize document with that DTD; is it possible to do + // better for the declaration of the root element? + // + // NOTE: can't use SAX2 to write internal subsets. + // + StringWriter writer = new StringWriter (); + + writer.write ("<!DOCTYPE "); + writer.write (rootName); + if (systemId != null) { + writer.write ("\n "); + if (publicId != null) { + writer.write ("PUBLIC '"); + writer.write (publicId); + writer.write ("'\n\t'"); + } else + writer.write ("SYSTEM '"); + writer.write (systemId); + writer.write ("'"); + } + writer.write (" [ "); + if (rootName == fakeRootName) { + writer.write ("\n<!ELEMENT "); + writer.write (rootName); + writer.write (" EMPTY>"); + } + if (internalSubset != null) + writer.write (internalSubset); + writer.write ("\n ]>"); + + if (minimalDocument != null) { + writer.write ("\n"); + writer.write (minimalDocument); + writer.write ("\n"); + } else { + writer.write (" <"); + writer.write (rootName); + writer.write ("/>\n"); + } + minimalDocument = writer.toString (); + + // + // OK, load it + // + XMLReader producer; + + producer = XMLReaderFactory.createXMLReader (); + bind (producer, this); + + if (resolver != null) + producer.setEntityResolver (resolver); + + InputSource in; + + in = new InputSource (new StringReader (minimalDocument)); + producer.parse (in); + + disableDeclarations = true; + if (rootName == fakeRootName) + this.rootName = null; + } + + private void resetState () + { + if (!disableReset) { + rootName = null; + contentStack.removeAllElements (); + elements.clear (); + ids.clear (); + + notations.removeAllElements (); + nDeferred.removeAllElements (); + unparsed.removeAllElements (); + uDeferred.removeAllElements (); + } + } + + + private void warning (String description) + throws SAXException + { + ErrorHandler errHandler = getErrorHandler (); + Locator locator = getDocumentLocator (); + SAXParseException err; + + if (errHandler == null) + return; + + if (locator == null) + err = new SAXParseException (description, null, null, -1, -1); + else + err = new SAXParseException (description, locator); + errHandler.warning (err); + } + + // package private (for ChildrenRecognizer) + private void error (String description) + throws SAXException + { + ErrorHandler errHandler = getErrorHandler (); + Locator locator = getDocumentLocator (); + SAXParseException err; + + if (locator == null) + err = new SAXParseException (description, null, null, -1, -1); + else + err = new SAXParseException (description, locator); + if (errHandler != null) + errHandler.error (err); + else // else we always treat it as fatal! + throw err; + } + + private void fatalError (String description) + throws SAXException + { + ErrorHandler errHandler = getErrorHandler (); + Locator locator = getDocumentLocator (); + SAXParseException err; + + if (locator != null) + err = new SAXParseException (description, locator); + else + err = new SAXParseException (description, null, null, -1, -1); + if (errHandler != null) + errHandler.fatalError (err); + // we always treat this as fatal, regardless of the handler + throw err; + } + + + private static boolean isExtender (char c) + { + // [88] Extender ::= ... + return c == 0x00b7 || c == 0x02d0 || c == 0x02d1 || c == 0x0387 + || c == 0x0640 || c == 0x0e46 || c == 0x0ec6 || c == 0x3005 + || (c >= 0x3031 && c <= 0x3035) + || (c >= 0x309d && c <= 0x309e) + || (c >= 0x30fc && c <= 0x30fe); + } + + + // use augmented Unicode rules, not full XML rules + private boolean isName (String name, String context, String id) + throws SAXException + { + char buf [] = name.toCharArray (); + boolean pass = true; + + if (!Character.isUnicodeIdentifierStart (buf [0]) + && ":_".indexOf (buf [0]) == -1) + pass = false; + else { + int max = buf.length; + for (int i = 1; pass && i < max; i++) { + char c = buf [i]; + if (!Character.isUnicodeIdentifierPart (c) + && ":-_.".indexOf (c) == -1 + && !isExtender (c)) + pass = false; + } + } + + if (!pass) + error ("In " + context + " for " + id + + ", '" + name + "' is not a name"); + return pass; // true == OK + } + + // use augmented Unicode rules, not full XML rules + private boolean isNmtoken (String nmtoken, String context, String id) + throws SAXException + { + char buf [] = nmtoken.toCharArray (); + boolean pass = true; + int max = buf.length; + + // XXX make this share code with isName + + for (int i = 0; pass && i < max; i++) { + char c = buf [i]; + if (!Character.isUnicodeIdentifierPart (c) + && ":-_.".indexOf (c) == -1 + && !isExtender (c)) + pass = false; + } + + if (!pass) + error ("In " + context + " for " + id + + ", '" + nmtoken + "' is not a name token"); + return pass; // true == OK + } + + private void checkEnumeration (String value, String type, String name) + throws SAXException + { + if (!hasMatch (value, type)) + // VC: Enumeration + error ("Value '" + value + + "' for attribute '" + name + + "' is not permitted: " + type); + } + + // used to test enumerated attributes and mixed content models + // package private + static boolean hasMatch (String value, String orList) + { + int len = value.length (); + int max = orList.length () - len; + + for (int start = 0; + (start = orList.indexOf (value, start)) != -1; + start++) { + char c; + + if (start > max) + break; + c = orList.charAt (start - 1); + if (c != '|' && c != '('/*)*/) + continue; + c = orList.charAt (start + len); + if (c != '|' && /*(*/ c != ')') + continue; + return true; + } + return false; + } + + /** + * <b>LexicalHandler</b> Records the declaration of the root + * element, so it can be verified later. + * Passed to the next consumer, unless this one was + * preloaded with a particular DTD. + */ + public void startDTD (String name, String publicId, String systemId) + throws SAXException + { + if (disableDeclarations) + return; + + rootName = name; + super.startDTD (name, publicId, systemId); + } + + /** + * <b>LexicalHandler</b> Verifies that all referenced notations + * and unparsed entities have been declared. + * Passed to the next consumer, unless this one was + * preloaded with a particular DTD. + */ + public void endDTD () + throws SAXException + { + if (disableDeclarations) + return; + + // this is a convenient hook for end-of-dtd checks, but we + // could also trigger it in the first startElement call. + // locator info is more appropriate here though. + + // VC: Notation Declared (NDATA can refer to them before decls, + // as can NOTATION attribute enumerations and defaults) + int length = nDeferred.size (); + for (int i = 0; i < length; i++) { + String notation = (String) nDeferred.elementAt (i); + if (!notations.contains (notation)) { + error ("A declaration referred to notation '" + notation + + "' which was never declared"); + } + } + nDeferred.removeAllElements (); + + // VC: Entity Name (attribute values can refer to them + // before they're declared); VC Attribute Default Legal + length = uDeferred.size (); + for (int i = 0; i < length; i++) { + String entity = (String) uDeferred.elementAt (i); + if (!unparsed.contains (entity)) { + error ("An attribute default referred to entity '" + entity + + "' which was never declared"); + } + } + uDeferred.removeAllElements (); + super.endDTD (); + } + + + // These are interned, so we can rely on "==" to find the type of + // all attributes except enumerations ... + // "(this|or|that|...)" and "NOTATION (this|or|that|...)" + static final String types [] = { + "CDATA", + "ID", "IDREF", "IDREFS", + "NMTOKEN", "NMTOKENS", + "ENTITY", "ENTITIES" + }; + + + /** + * <b>DecllHandler</b> Records attribute declaration for later use + * in validating document content, and checks validity constraints + * that are applicable to attribute declarations. + * Passed to the next consumer, unless this one was + * preloaded with a particular DTD. + */ + public void attributeDecl ( + String eName, + String aName, + String type, + String mode, + String value + ) throws SAXException + { + if (disableDeclarations) + return; + + ElementInfo info = (ElementInfo) elements.get (eName); + AttributeInfo ainfo = new AttributeInfo (); + boolean checkOne = false; + boolean interned = false; + + // cheap interning of type names and #FIXED, #REQUIRED + // for faster startElement (we can use "==") + for (int i = 0; i < types.length; i++) { + if (types [i].equals (type)) { + type = types [i]; + interned = true; + break; + } + } + if ("#FIXED".equals (mode)) + mode = "#FIXED"; + else if ("#REQUIRED".equals (mode)) + mode = "#REQUIRED"; + + ainfo.type = type; + ainfo.mode = mode; + ainfo.value = value; + + // we might not have seen the content model yet + if (info == null) { + info = new ElementInfo (eName); + elements.put (eName, info); + } + if ("ID" == type) { + checkOne = true; + if (!("#REQUIRED" == mode || "#IMPLIED".equals (mode))) { + // VC: ID Attribute Default + error ("ID attribute '" + aName + + "' must be #IMPLIED or #REQUIRED"); + } + + } else if (!interned && type.startsWith ("NOTATION ")) { + checkOne = true; + + // VC: Notation Attributes (notations must be declared) + StringTokenizer tokens = new StringTokenizer ( + type.substring (10, type.lastIndexOf (')')), + "|"); + while (tokens.hasMoreTokens ()) { + String token = tokens.nextToken (); + if (!notations.contains (token)) + nDeferred.addElement (token); + } + } + if (checkOne) { + for (Enumeration e = info.attributes.keys (); + e.hasMoreElements (); + /* NOP */) { + String name; + AttributeInfo ainfo2; + + name = (String) e.nextElement (); + ainfo2 = (AttributeInfo) info.attributes.get (name); + if (type == ainfo2.type || !interned /* NOTATION */) { + // VC: One ID per Element Type + // VC: One Notation per Element TYpe + error ("Element '" + eName + + "' already has an attribute of type " + + (interned ? "NOTATION" : type) + + " ('" + name + + "') so '" + aName + + "' is a validity error"); + } + } + } + + // VC: Attribute Default Legal + if (value != null) { + + if ("CDATA" == type) { + // event source rejected '<' + + } else if ("NMTOKEN" == type) { + // VC: Name Token (is a nmtoken) + isNmtoken (value, "attribute default", aName); + + } else if ("NMTOKENS" == type) { + // VC: Name Token (is a nmtoken; at least one value) + StringTokenizer tokens = new StringTokenizer (value); + if (!tokens.hasMoreTokens ()) + error ("Default for attribute '" + aName + + "' must have at least one name token."); + else do { + String token = tokens.nextToken (); + isNmtoken (token, "attribute default", aName); + } while (tokens.hasMoreTokens ()); + + } else if ("IDREF" == type || "ENTITY" == type) { + // VC: Entity Name (is a name) + // VC: IDREF (is a name) (is declared) + isName (value, "attribute default", aName); + if ("ENTITY" == type && !unparsed.contains (value)) + uDeferred.addElement (value); + + } else if ("IDREFS" == type || "ENTITIES" == type) { + // VC: Entity Name (is a name; at least one value) + // VC: IDREF (is a name; at least one value) + StringTokenizer names = new StringTokenizer (value); + if (!names.hasMoreTokens ()) + error ("Default for attribute '" + aName + + "' must have at least one name."); + else do { + String name = names.nextToken (); + isName (name, "attribute default", aName); + if ("ENTITIES" == type && !unparsed.contains (name)) + uDeferred.addElement (value); + } while (names.hasMoreTokens ()); + + } else if (type.charAt (0) == '(' /*)*/ ) { + // VC: Enumeration (must match) + checkEnumeration (value, type, aName); + + } else if (!interned && checkOne) { /* NOTATION */ + // VC: Notation attributes (must be names) + isName (value, "attribute default", aName); + + // VC: Notation attributes (must be declared) + if (!notations.contains (value)) + nDeferred.addElement (value); + + // VC: Enumeration (must match) + checkEnumeration (value, type, aName); + + } else if ("ID" != type) + throw new RuntimeException ("illegal attribute type: " + type); + } + + if (info.attributes.get (aName) == null) + info.attributes.put (aName, ainfo); + /* + else + warning ("Element '" + eName + + "' already has an attribute named '" + aName + "'"); + */ + + if ("xml:space".equals (aName)) { + if (!("(default|preserve)".equals (type) + || "(preserve|default)".equals (type) + // these next two are arguable; XHTML's DTD doesn't + // deserve errors. After all, it's not like any + // illegal _value_ could pass ... + || "(preserve)".equals (type) + || "(default)".equals (type) + )) + error ( + "xml:space attribute type must be like '(default|preserve)'" + + " not '" + type + "'" + ); + + } + super.attributeDecl (eName, aName, type, mode, value); + } + + /** + * <b>DecllHandler</b> Records the element declaration for later use + * when checking document content, and checks validity constraints that + * apply to element declarations. Passed to the next consumer, unless + * this one was preloaded with a particular DTD. + */ + public void elementDecl (String name, String model) + throws SAXException + { + if (disableDeclarations) + return; + + ElementInfo info = (ElementInfo) elements.get (name); + + // we might have seen an attribute decl already + if (info == null) { + info = new ElementInfo (name); + elements.put (name, info); + } + if (info.model != null) { + // NOTE: not all parsers can report such duplicates. + // VC: Unique Element Type Declaration + error ("Element type '" + name + + "' was already declared."); + } else { + info.model = model; + + // VC: No Duplicate Types (in mixed content models) + if (model.charAt (1) == '#') // (#PCDATA... + info.getRecognizer (this); + } + super.elementDecl (name, model); + } + + /** + * <b>DecllHandler</b> passed to the next consumer, unless this + * one was preloaded with a particular DTD + */ + public void internalEntityDecl (String name, String value) + throws SAXException + { + if (!disableDeclarations) + super.internalEntityDecl (name, value); + } + + /** + * <b>DecllHandler</b> passed to the next consumer, unless this + * one was preloaded with a particular DTD + */ + public void externalEntityDecl (String name, + String publicId, String systemId) + throws SAXException + { + if (!disableDeclarations) + super.externalEntityDecl (name, publicId, systemId); + } + + + /** + * <b>DTDHandler</b> Records the notation name, for checking + * NOTATIONS attribute values and declararations of unparsed + * entities. Passed to the next consumer, unless this one was + * preloaded with a particular DTD. + */ + public void notationDecl (String name, String publicId, String systemId) + throws SAXException + { + if (disableDeclarations) + return; + + notations.addElement (name); + super.notationDecl (name, publicId, systemId); + } + + /** + * <b>DTDHandler</b> Records the entity name, for checking + * ENTITY and ENTITIES attribute values; records the notation + * name if it hasn't yet been declared. Passed to the next consumer, + * unless this one was preloaded with a particular DTD. + */ + public void unparsedEntityDecl ( + String name, + String publicId, + String systemId, + String notationName + ) throws SAXException + { + if (disableDeclarations) + return; + + unparsed.addElement (name); + if (!notations.contains (notationName)) + nDeferred.addElement (notationName); + super.unparsedEntityDecl (name, publicId, systemId, notationName); + } + + + /** + * <b>ContentHandler</b> Ensures that state from any previous parse + * has been deleted. + * Passed to the next consumer. + */ + public void startDocument () + throws SAXException + { + resetState (); + super.startDocument (); + } + + + private static boolean isAsciiLetter (char c) + { + return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); + } + + + /** + * <b>ContentHandler</b> Reports a fatal exception. Validating + * XML processors may not skip any entities. + */ + public void skippedEntity (String name) + throws SAXException + { + fatalError ("may not skip entities"); + } + + /* + * SAX2 doesn't expand non-PE refs in attribute defaults... + */ + private String expandDefaultRefs (String s) + throws SAXException + { + if (s.indexOf ('&') < 0) + return s; + +// FIXME: handle &#nn; &#xnn; &name; + String message = "Can't expand refs in attribute default: " + s; + warning (message); + + return s; + } + + /** + * <b>ContentHandler</b> Performs validity checks against element + * (and document) content models, and attribute values. + * Passed to the next consumer. + */ + public void startElement ( + String uri, + String localName, + String qName, + Attributes atts + ) throws SAXException + { + // + // First check content model for the enclosing scope. + // + if (contentStack.isEmpty ()) { + // VC: Root Element Type + if (!qName.equals (rootName)) { + if (rootName == null) + warning ("This document has no DTD, can't be valid"); + else + error ("Root element type '" + qName + + "' was declared to be '" + rootName + "'"); + } + } else { + Recognizer state = (Recognizer) contentStack.peek (); + + if (state != null) { + Recognizer newstate = state.acceptElement (qName); + + if (newstate == null) + error ("Element type '" + qName + + "' in element '" + state.type.name + + "' violates content model " + state.type.model + ); + if (newstate != state) { + contentStack.pop (); + contentStack.push (newstate); + } + } + } + + // + // Then check that this element was declared, and push the + // object used to validate its content model onto our stack. + // + // This is where the recognizer gets created, if needed; if + // it's a "children" (elements) content model, an NDFA is + // created. (One recognizer is used per content type, no + // matter how complex that recognizer is.) + // + ElementInfo info; + + info = (ElementInfo) elements.get (qName); + if (info == null || info.model == null) { + // VC: Element Valid (base clause) + error ("Element type '" + qName + "' was not declared"); + contentStack.push (null); + + // for less diagnostic noise, fake a declaration. + elementDecl (qName, "ANY"); + } else + contentStack.push (info.getRecognizer (this)); + + // + // Then check each attribute present + // + int len; + String aname; + AttributeInfo ainfo; + + if (atts != null) + len = atts.getLength (); + else + len = 0; + + for (int i = 0; i < len; i++) { + aname = atts.getQName (i); + + if (info == null + || (ainfo = (AttributeInfo) info.attributes.get (aname)) + == null) { + // VC: Attribute Value Type + error ("Attribute '" + aname + + "' was not declared for element type " + qName); + continue; + } + + String value = atts.getValue (i); + + // note that "==" for type names and "#FIXED" is correct + // (and fast) since we've interned those literals. + + if ("#FIXED" == ainfo.mode) { + String expanded = expandDefaultRefs (ainfo.value); + + // VC: Fixed Attribute Default + if (!value.equals (expanded)) { + error ("Attribute '" + aname + + "' must match " + expanded + ); + continue; + } + } + + if ("CDATA" == ainfo.type) + continue; + + // + // For all other attribute types, there are various + // rules to follow. + // + + if ("ID" == ainfo.type) { + // VC: ID (must be a name) + if (isName (value, "ID attribute", aname)) { + if (Boolean.TRUE == ids.get (value)) + // VC: ID (appears once) + error ("ID attribute " + aname + + " uses an ID value '" + value + + "' which was already declared."); + else + // any forward refs are no longer problems + ids.put (value, Boolean.TRUE); + } + continue; + } + + if ("IDREF" == ainfo.type) { + // VC: IDREF (value must be a name) + if (isName (value, "IDREF attribute", aname)) { + // VC: IDREF (must match some ID attribute) + if (ids.get (value) == null) + // new -- assume it's a forward ref + ids.put (value, Boolean.FALSE); + } + continue; + } + + if ("IDREFS" == ainfo.type) { + StringTokenizer tokens = new StringTokenizer (value, " "); + + if (!tokens.hasMoreTokens ()) { + // VC: IDREF (one or more values) + error ("IDREFS attribute " + aname + + " must have at least one ID ref"); + } else do { + String id = tokens.nextToken (); + + // VC: IDREF (value must be a name) + if (isName (id, "IDREFS attribute", aname)) { + // VC: IDREF (must match some ID attribute) + if (ids.get (id) == null) + // new -- assume it's a forward ref + ids.put (id, Boolean.FALSE); + } + } while (tokens.hasMoreTokens ()); + continue; + } + + if ("NMTOKEN" == ainfo.type) { + // VC: Name Token (is a name token) + isNmtoken (value, "NMTOKEN attribute", aname); + continue; + } + + if ("NMTOKENS" == ainfo.type) { + StringTokenizer tokens = new StringTokenizer (value, " "); + + if (!tokens.hasMoreTokens ()) { + // VC: Name Token (one or more values) + error ("NMTOKENS attribute " + aname + + " must have at least one name token"); + } else do { + String token = tokens.nextToken (); + + // VC: Name Token (is a name token) + isNmtoken (token, "NMTOKENS attribute", aname); + } while (tokens.hasMoreTokens ()); + continue; + } + + if ("ENTITY" == ainfo.type) { + if (!unparsed.contains (value)) + // VC: Entity Name + error ("Value of attribute '" + aname + + "' refers to unparsed entity '" + value + + "' which was not declared."); + continue; + } + + if ("ENTITIES" == ainfo.type) { + StringTokenizer tokens = new StringTokenizer (value, " "); + + if (!tokens.hasMoreTokens ()) { + // VC: Entity Name (one or more values) + error ("ENTITIES attribute " + aname + + " must have at least one name token"); + } else do { + String entity = tokens.nextToken (); + + if (!unparsed.contains (entity)) + // VC: Entity Name + error ("Value of attribute '" + aname + + "' refers to unparsed entity '" + entity + + "' which was not declared."); + } while (tokens.hasMoreTokens ()); + continue; + } + + // + // check for enumerations last; more expensive + // + if (ainfo.type.charAt (0) == '(' /*)*/ + || ainfo.type.startsWith ("NOTATION ") + ) { + // VC: Enumeration (value must be defined) + checkEnumeration (value, ainfo.type, aname); + continue; + } + } + + // + // Last, check that all #REQUIRED attributes were provided + // + if (info != null) { + Hashtable table = info.attributes; + + if (table.size () != 0) { + Enumeration e = table.keys (); + + // XXX table.keys uses the heap, bleech -- slows things + + while (e.hasMoreElements ()) { + aname = (String) e.nextElement (); + ainfo = (AttributeInfo) table.get (aname); + + // "#REQUIRED" mode was interned in attributeDecl + if ("#REQUIRED" == ainfo.mode + && atts.getValue (aname) == null) { + // VC: Required Attribute + error ("Attribute '" + aname + "' must be specified " + + "for element type " + qName); + } + } + } + } + super.startElement (uri, localName, qName, atts); + } + + /** + * <b>ContentHandler</b> Reports a validity error if the element's content + * model does not permit character data. + * Passed to the next consumer. + */ + public void characters (char ch [], int start, int length) + throws SAXException + { + Recognizer state; + + if (contentStack.empty ()) + state = null; + else + state = (Recognizer) contentStack.peek (); + + // NOTE: if this ever supports with SAX parsers that don't + // report ignorable whitespace as such (only XP?), this class + // needs to morph it into ignorableWhitespace() as needed ... + + if (state != null && !state.acceptCharacters ()) + // VC: Element Valid (clauses three, four -- see recognizer) + error ("Character content not allowed in element " + + state.type.name); + + super.characters (ch, start, length); + } + + + /** + * <b>ContentHandler</b> Reports a validity error if the element's content + * model does not permit end-of-element yet, or a well formedness error + * if there was no matching startElement call. + * Passed to the next consumer. + */ + public void endElement (String uri, String localName, String qName) + throws SAXException + { + try { + Recognizer state = (Recognizer) contentStack.pop (); + + if (state != null && !state.completed ()) + // VC: Element valid (clauses two, three, four; see Recognizer) + error ("Premature end for element '" + + state.type.name + + "', content model " + + state.type.model); + + // could insist on match of start element, but that's + // something the input stream must to guarantee. + + } catch (EmptyStackException e) { + fatalError ("endElement without startElement: " + qName + + ((uri == null) + ? "" + : ( " { '" + uri + "', " + localName + " }"))); + } + super.endElement (uri, localName, qName); + } + + /** + * <b>ContentHandler</b> Checks whether all ID values that were + * referenced have been declared, and releases all resources. + * Passed to the next consumer. + * + * @see #setDocumentLocator + */ + public void endDocument () + throws SAXException + { + for (Enumeration idNames = ids.keys (); + idNames.hasMoreElements (); + /* NOP */) { + String id = (String) idNames.nextElement (); + + if (Boolean.FALSE == ids.get (id)) { + // VC: IDREF (must match ID) + error ("Undeclared ID value '" + id + + "' was referred to by an IDREF/IDREFS attribute"); + } + } + + resetState (); + super.endDocument (); + } + + + /** Holds per-element declarations */ + static private final class ElementInfo + { + String name; + String model; + + // key = attribute name; value = AttributeInfo + Hashtable attributes = new Hashtable (11); + + ElementInfo (String n) { name = n; } + + private Recognizer recognizer; + + // for validating content models: one per type, shared, + // and constructed only on demand ... so unused elements do + // not need to consume resources. + Recognizer getRecognizer (ValidationConsumer consumer) + throws SAXException + { + if (recognizer == null) { + if ("ANY".equals (model)) + recognizer = ANY; + else if ("EMPTY".equals (model)) + recognizer = new EmptyRecognizer (this); + else if ('#' == model.charAt (1)) + // n.b. this constructor does a validity check + recognizer = new MixedRecognizer (this, consumer); + else + recognizer = new ChildrenRecognizer (this, consumer); + } + return recognizer; + } + } + + /** Holds per-attribute declarations */ + static private final class AttributeInfo + { + String type; + String mode; // #REQUIRED, etc (or null) + String value; // or null + } + + + // + // Content model validation + // + + static private final Recognizer ANY = new Recognizer (null); + + + // Base class defines the calls used to validate content, + // and supports the "ANY" content model + static private class Recognizer + { + final ElementInfo type; + + Recognizer (ElementInfo t) { type = t; } + + // return true iff character data is legal here + boolean acceptCharacters () + throws SAXException + // VC: Element Valid (third and fourth clauses) + { return true; } + + // null return = failure + // otherwise, next state (like an FSM) + // prerequisite: tested that name was declared + Recognizer acceptElement (String name) + throws SAXException + // VC: Element Valid (fourth clause) + { return this; } + + // return true iff model is completed, can finish + boolean completed () + throws SAXException + // VC: Element Valid (fourth clause) + { return true; } + + public String toString () + // n.b. "children" is the interesting case! + { return (type == null) ? "ANY" : type.model; } + } + + // "EMPTY" content model -- no characters or elements + private static final class EmptyRecognizer extends Recognizer + { + public EmptyRecognizer (ElementInfo type) + { super (type); } + + // VC: Element Valid (first clause) + boolean acceptCharacters () + { return false; } + + // VC: Element Valid (first clause) + Recognizer acceptElement (String name) + { return null; } + } + + // "Mixed" content model -- ANY, but restricts elements + private static final class MixedRecognizer extends Recognizer + { + private String permitted []; + + // N.B. constructor tests for duplicated element names (VC) + public MixedRecognizer (ElementInfo t, ValidationConsumer v) + throws SAXException + { + super (t); + + // (#PCDATA...)* or (#PCDATA) ==> ... or empty + // with the "..." being "|elname|..." + StringTokenizer tokens = new StringTokenizer ( + t.model.substring (8, t.model.lastIndexOf (')')), + "|"); + Vector vec = new Vector (); + + while (tokens.hasMoreTokens ()) { + String token = tokens.nextToken (); + + if (vec.contains (token)) + v.error ("element " + token + + " is repeated in mixed content model: " + + t.model); + else + vec.addElement (token.intern ()); + } + permitted = new String [vec.size ()]; + for (int i = 0; i < permitted.length; i++) + permitted [i] = (String) vec.elementAt (i); + + // in one large machine-derived DTD sample, most of about + // 250 mixed content models were empty, and 25 had ten or + // more entries. 2 had over a hundred elements. Linear + // search isn't obviously wrong. + } + + // VC: Element Valid (third clause) + Recognizer acceptElement (String name) + { + int length = permitted.length; + + // first pass -- optimistic w.r.t. event source interning + // (and document validity) + for (int i = 0; i < length; i++) + if (permitted [i] == name) + return this; + // second pass -- pessimistic w.r.t. event source interning + for (int i = 0; i < length; i++) + if (permitted [i].equals (name)) + return this; + return null; + } + } + + + // recognizer loop flags, see later + private static final int F_LOOPHEAD = 0x01; + private static final int F_LOOPNEXT = 0x02; + + // for debugging -- used to label/count nodes in toString() + private static int nodeCount; + + /** + * "Children" content model -- these are nodes in NDFA state graphs. + * They work in fixed space. Note that these graphs commonly have + * cycles, handling features such as zero-or-more and one-or-more. + * + * <p>It's readonly, so only one copy is ever needed. The content model + * stack may have any number of pointers into each graph, when a model + * happens to be needed more than once due to element nesting. Since + * traversing the graph just moves to another node, and never changes + * it, traversals never interfere with each other. + * + * <p>There is an option to report non-deterministic models. These are + * always XML errors, but ones which are not often reported despite the + * fact that they can lead to different validating parsers giving + * different results for the same input. (The XML spec doesn't require + * them to be reported.) + * + * <p><b>FIXME</b> There's currently at least one known bug here, in that + * it's not actually detecting the non-determinism it tries to detect. + * (Of the "optional.xml" test, the once-or-twice-2* tests are all non-D; + * maybe some others.) This may relate to the issue flagged below as + * "should not" happen (but it was), which showed up when patching the + * graph to have one exit node (or more EMPTY nodes). + */ + private static final class ChildrenRecognizer extends Recognizer + implements Cloneable + { + // for reporting non-deterministic content models + // ... a waste of space if we're not reporting those! + // ... along with the 'model' member (in base class) + private ValidationConsumer consumer; + + // for CHOICE nodes -- each component is an arc that + // accepts a different NAME (or is EMPTY indicating + // NDFA termination). + private Recognizer components []; + + // for NAME/SEQUENCE nodes -- accepts that NAME and + // then goes to the next node (CHOICE, NAME, EMPTY). + private String name; + private Recognizer next; + + // loops always point back to a CHOICE node. we mark such choice + // nodes (F_LOOPHEAD) for diagnostics and faster deep cloning. + // We also mark nodes before back pointers (F_LOOPNEXT), to ensure + // termination when we patch sequences and loops. + private int flags; + + + // prevent a needless indirection between 'this' and 'node' + private void copyIn (ChildrenRecognizer node) + { + // model & consumer are already set + components = node.components; + name = node.name; + next = node.next; + flags = node.flags; + } + + // used to construct top level "children" content models, + public ChildrenRecognizer (ElementInfo type, ValidationConsumer vc) + { + this (vc, type); + populate (type.model.toCharArray (), 0); + patchNext (new EmptyRecognizer (type), null); + } + + // used internally; populating is separate + private ChildrenRecognizer (ValidationConsumer vc, ElementInfo type) + { + super (type); + consumer = vc; + } + + + // + // When rewriting some graph nodes we need deep clones in one case; + // mostly shallow clones (what the JVM handles for us) are fine. + // + private ChildrenRecognizer shallowClone () + { + try { + return (ChildrenRecognizer) clone (); + } catch (CloneNotSupportedException e) { + throw new Error ("clone"); + } + } + + private ChildrenRecognizer deepClone () + { + return deepClone (new Hashtable (37)); + } + + private ChildrenRecognizer deepClone (Hashtable table) + { + ChildrenRecognizer retval; + + if ((flags & F_LOOPHEAD) != 0) { + retval = (ChildrenRecognizer) table.get (this); + if (retval != null) + return this; + + retval = shallowClone (); + table.put (this, retval); + } else + retval = shallowClone (); + + if (next != null) { + if (next instanceof ChildrenRecognizer) + retval.next = ((ChildrenRecognizer)next) + .deepClone (table); + else if (!(next instanceof EmptyRecognizer)) + throw new RuntimeException ("deepClone"); + } + + if (components != null) { + retval.components = new Recognizer [components.length]; + for (int i = 0; i < components.length; i++) { + Recognizer temp = components [i]; + + if (temp == null) + retval.components [i] = null; + else if (temp instanceof ChildrenRecognizer) + retval.components [i] = ((ChildrenRecognizer)temp) + .deepClone (table); + else if (!(temp instanceof EmptyRecognizer)) + throw new RuntimeException ("deepClone"); + } + } + + return retval; + } + + // connect subgraphs, first to next (sequencing) + private void patchNext (Recognizer theNext, Hashtable table) + { + // backpointers must not be repatched or followed + if ((flags & F_LOOPNEXT) != 0) + return; + + // XXX this table "shouldn't" be needed, right? + // but some choice nodes looped if it isn't there. + if (table != null && table.get (this) != null) + return; + if (table == null) + table = new Hashtable (); + + // NAME/SEQUENCE + if (name != null) { + if (next == null) + next = theNext; + else if (next instanceof ChildrenRecognizer) { + ((ChildrenRecognizer)next).patchNext (theNext, table); + } else if (!(next instanceof EmptyRecognizer)) + throw new RuntimeException ("patchNext"); + return; + } + + // CHOICE + for (int i = 0; i < components.length; i++) { + if (components [i] == null) + components [i] = theNext; + else if (components [i] instanceof ChildrenRecognizer) { + ((ChildrenRecognizer)components [i]) + .patchNext (theNext, table); + } else if (!(components [i] instanceof EmptyRecognizer)) + throw new RuntimeException ("patchNext"); + } + + if (table != null && (flags & F_LOOPHEAD) != 0) + table.put (this, this); + } + + /** + * Parses a 'children' spec (or recursively 'cp') and makes this + * become a regular graph node. + * + * @return index after this particle + */ + private int populate (char parseBuf [], int startPos) + { + int nextPos = startPos + 1; + char c; + + if (nextPos < 0 || nextPos >= parseBuf.length) + throw new IndexOutOfBoundsException (); + + // Grammar of the string is from the XML spec, but + // with whitespace removed by the SAX parser. + + // children ::= (choice | seq) ('?' | '*' | '+')? + // cp ::= (Name | choice | seq) ('?' | '*' | '+')? + // choice ::= '(' cp ('|' choice)* ')' + // seq ::= '(' cp (',' choice)* ')' + + // interior nodes only + // cp ::= name ... + if (parseBuf [startPos] != '('/*)*/) { + boolean done = false; + do { + switch (c = parseBuf [nextPos]) { + case '?': case '*': case '+': + case '|': case ',': + case /*(*/ ')': + done = true; + continue; + default: + nextPos++; + continue; + } + } while (!done); + name = new String (parseBuf, startPos, nextPos - startPos); + + // interior OR toplevel nodes + // cp ::= choice .. + // cp ::= seq .. + } else { + // collect everything as a separate list, and merge it + // into "this" later if we can (SEQUENCE or singleton) + ChildrenRecognizer first; + + first = new ChildrenRecognizer (consumer, type); + nextPos = first.populate (parseBuf, nextPos); + c = parseBuf [nextPos++]; + + if (c == ',' || c == '|') { + ChildrenRecognizer current = first; + char separator = c; + Vector v = null; + + if (separator == '|') { + v = new Vector (); + v.addElement (first); + } + + do { + ChildrenRecognizer link; + + link = new ChildrenRecognizer (consumer, type); + nextPos = link.populate (parseBuf, nextPos); + + if (separator == ',') { + current.patchNext (link, null); + current = link; + } else + v.addElement (link); + + c = parseBuf [nextPos++]; + } while (c == separator); + + // choice ... collect everything into one array. + if (separator == '|') { + // assert v.size() > 1 + components = new Recognizer [v.size ()]; + for (int i = 0; i < components.length; i++) { + components [i] = (Recognizer) + v.elementAt (i); + } + // assert flags == 0 + + // sequence ... merge into "this" to be smaller. + } else + copyIn (first); + + // treat singletons like one-node sequences. + } else + copyIn (first); + + if (c != /*(*/ ')') + throw new RuntimeException ("corrupt content model"); + } + + // + // Arity is optional, and the root of all fun. We keep the + // FSM state graph simple by only having NAME/SEQUENCE and + // CHOICE nodes (or EMPTY to terminate a model), easily + // evaluated. So we rewrite each node that has arity, using + // those primitives. We create loops here, if needed. + // + if (nextPos < parseBuf.length) { + c = parseBuf [nextPos]; + if (c == '?' || c == '*' || c == '+') { + nextPos++; + + // Rewrite 'zero-or-one' "?" arity to a CHOICE: + // - SEQUENCE (clone, what's next) + // - or, what's next + // Size cost: N --> N + 1 + if (c == '?') { + Recognizer once = shallowClone (); + + components = new Recognizer [2]; + components [0] = once; + // components [1] initted to null + name = null; + next = null; + flags = 0; + + + // Rewrite 'zero-or-more' "*" arity to a CHOICE. + // - LOOP (clone, back to this CHOICE) + // - or, what's next + // Size cost: N --> N + 1 + } else if (c == '*') { + ChildrenRecognizer loop = shallowClone (); + + loop.patchNext (this, null); + loop.flags |= F_LOOPNEXT; + flags = F_LOOPHEAD; + + components = new Recognizer [2]; + components [0] = loop; + // components [1] initted to null + name = null; + next = null; + + + // Rewrite 'one-or-more' "+" arity to a SEQUENCE. + // Basically (a)+ --> ((a),(a)*). + // - this + // - CHOICE + // * LOOP (clone, back to the CHOICE) + // * or, whatever's next + // Size cost: N --> 2N + 1 + } else if (c == '+') { + ChildrenRecognizer loop = deepClone (); + ChildrenRecognizer choice; + + choice = new ChildrenRecognizer (consumer, type); + loop.patchNext (choice, null); + loop.flags |= F_LOOPNEXT; + choice.flags = F_LOOPHEAD; + + choice.components = new Recognizer [2]; + choice.components [0] = loop; + // choice.components [1] initted to null + // choice.name, choice.next initted to null + + patchNext (choice, null); + } + } + } + + return nextPos; + } + + // VC: Element Valid (second clause) + boolean acceptCharacters () + { return false; } + + // VC: Element Valid (second clause) + Recognizer acceptElement (String type) + throws SAXException + { + // NAME/SEQUENCE + if (name != null) { + if (name.equals (type)) + return next; + return null; + } + + // CHOICE ... optionally reporting nondeterminism we + // run across. we won't check out every transition + // for nondeterminism; only the ones we follow. + Recognizer retval = null; + + for (int i = 0; i < components.length; i++) { + Recognizer temp = components [i].acceptElement (type); + + if (temp == null) + continue; + else if (!warnNonDeterministic) + return temp; + else if (retval == null) + retval = temp; + else if (retval != temp) + consumer.error ("Content model " + this.type.model + + " is non-deterministic for " + type); + } + return retval; + } + + // VC: Element Valid (second clause) + boolean completed () + throws SAXException + { + // expecting a specific element + if (name != null) + return false; + + // choice, some sequences + for (int i = 0; i < components.length; i++) { + if (components [i].completed ()) + return true; + } + + return false; + } + +/** / + // FOR DEBUGGING ... flattens the graph for printing. + + public String toString () + { + StringBuffer buf = new StringBuffer (); + + // only one set of loop labels can be generated + // at a time... + synchronized (ANY) { + nodeCount = 0; + + toString (buf, new Hashtable ()); + return buf.toString (); + } + } + + private void toString (StringBuffer buf, Hashtable table) + { + // When we visit a node, label and count it. + // Nodes are never visited/counted more than once. + // For small models labels waste space, but if arity + // mappings were used the savings are substantial. + // (Plus, the output can be more readily understood.) + String temp = (String) table.get (this); + + if (temp != null) { + buf.append ('{'); + buf.append (temp); + buf.append ('}'); + return; + } else { + StringBuffer scratch = new StringBuffer (15); + + if ((flags & F_LOOPHEAD) != 0) + scratch.append ("loop"); + else + scratch.append ("node"); + scratch.append ('-'); + scratch.append (++nodeCount); + temp = scratch.toString (); + + table.put (this, temp); + buf.append ('['); + buf.append (temp); + buf.append (']'); + buf.append (':'); + } + + // NAME/SEQUENCE + if (name != null) { + // n.b. some output encodings turn some name chars into '?' + // e.g. with Japanese names and ASCII output + buf.append (name); + if (components != null) // bug! + buf.append ('$'); + if (next == null) + buf.append (",*"); + else if (next instanceof EmptyRecognizer) // patch-to-next + buf.append (",{}"); + else if (next instanceof ChildrenRecognizer) { + buf.append (','); + ((ChildrenRecognizer)next).toString (buf, table); + } else // bug! + buf.append (",+"); + return; + } + + // CHOICE + buf.append ("<"); + for (int i = 0; i < components.length; i++) { + if (i != 0) + buf.append ("|"); + if (components [i] instanceof EmptyRecognizer) { + buf.append ("{}"); + } else if (components [i] == null) { // patch-to-next + buf.append ('*'); + } else { + ChildrenRecognizer r; + + r = (ChildrenRecognizer) components [i]; + r.toString (buf, table); + } + } + buf.append (">"); + } +/**/ + } +} |