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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/xml/xpath/Steps.java | |
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Diffstat (limited to 'libjava/classpath/gnu/xml/xpath/Steps.java')
-rw-r--r-- | libjava/classpath/gnu/xml/xpath/Steps.java | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/xml/xpath/Steps.java b/libjava/classpath/gnu/xml/xpath/Steps.java new file mode 100644 index 000000000..75644541c --- /dev/null +++ b/libjava/classpath/gnu/xml/xpath/Steps.java @@ -0,0 +1,260 @@ +/* Steps.java -- + Copyright (C) 2004 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.xpath; + +import gnu.java.lang.CPStringBuilder; + +import java.util.Collection; +import java.util.Collections; +import java.util.Iterator; +import java.util.LinkedHashSet; +import java.util.LinkedList; +import java.util.Set; +import javax.xml.namespace.QName; +import org.w3c.dom.Attr; +import org.w3c.dom.Node; + +/** + * A list of transitions between components in a location path. + * + * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a> + */ +public final class Steps + extends Path +{ + + final LinkedList<Expr> path; + + public Steps() + { + this(new LinkedList<Expr>()); + } + + Steps(LinkedList<Expr> path) + { + this.path = path; + } + + public boolean matches(Node context) + { + // Right to left + return matches(context, path.size() - 1); + } + + boolean matches(Node context, int pos) + { + Pattern right = (Pattern) path.get(pos); + if (!right.matches(context)) + { + return false; + } + if (pos > 0) + { + Pattern left = (Pattern) path.get(pos - 1); + for (Node candidate : possibleContexts(right, context)) + { + if (left.matches(candidate) && + matches(candidate, pos - 1)) + { + return true; + } + // keep going, there may be another candidate + } + return false; + } + return true; + } + + /** + * Essentially the reverse of Selector.addCandidates. + * The idea is to determine possible context nodes for a match. + */ + Collection<Node> possibleContexts(Pattern pattern, Node context) + { + if (pattern instanceof Selector) + { + Selector s = (Selector) pattern; + Collection<Node> candidates = new LinkedHashSet<Node>(); + switch (s.axis) + { + case Selector.PARENT: + s.addChildNodes(context, candidates, false); + break; + case Selector.ANCESTOR: + s.addChildNodes(context, candidates, true); + break; + case Selector.ANCESTOR_OR_SELF: + candidates.add (context); + s.addChildNodes(context, candidates, true); + break; + case Selector.CHILD: + s.addParentNode(context, candidates, false); + break; + case Selector.DESCENDANT: + s.addParentNode(context, candidates, true); + break; + case Selector.DESCENDANT_OR_SELF: + candidates.add(context); + s.addParentNode(context, candidates, true); + break; + case Selector.PRECEDING_SIBLING: + s.addFollowingNodes(context, candidates, false); + break; + case Selector.FOLLOWING_SIBLING: + s.addPrecedingNodes(context, candidates, false); + break; + case Selector.PRECEDING: + s.addFollowingNodes(context, candidates, true); + break; + case Selector.FOLLOWING: + s.addPrecedingNodes(context, candidates, true); + break; + case Selector.ATTRIBUTE: + case Selector.NAMESPACE: + if (context.getNodeType() == Node.ATTRIBUTE_NODE) + { + candidates.add(((Attr) context).getOwnerElement()); + } + break; + case Selector.SELF: + candidates.add(context); + break; + } + return candidates; + } + return Collections.emptySet(); + } + + @Override + public Object evaluate(Node context, int pos, int len) + { + //System.err.println(toString()+" evaluate"); + // Left to right + Iterator<Expr> i = path.iterator(); + Expr lhs = i.next(); + Object val = lhs.evaluate(context, pos, len); + //System.err.println("\tevaluate "+lhs+" = "+val); + while (val instanceof Collection && i.hasNext()) + { + Path rhs = (Path) i.next(); + /* Suppression is safe, as we know context produces Collection<Node> */ + @SuppressWarnings("unchecked") + Collection<Node> nodes = (Collection<Node>) val; + val = rhs.evaluate(context, nodes); + //System.err.println("\tevaluate "+rhs+" = "+val); + } + return val; + } + + @Override + Collection<Node> evaluate(Node context, Collection<Node> ns) + { + // Left to right + Iterator<Expr> i = path.iterator(); + Expr lhs = i.next(); + if (lhs instanceof Path) + { + ns = ((Path) lhs).evaluate(context, ns); + } + else + { + Set<Node> acc = new LinkedHashSet<Node>(); + int pos = 1, len = ns.size(); + for (Node node : ns) + { + Object ret = lhs.evaluate(node, pos++, len); + if (ret instanceof Collection) + { + /* Suppression is safe, as we know context produces Collection<Node> */ + @SuppressWarnings("unchecked") + Collection<Node> nodes = (Collection<Node>) ret; + acc.addAll(nodes); + } + } + ns = acc; + } + while (i.hasNext()) + { + Path rhs = (Path) i.next(); + ns = rhs.evaluate(context, ns); + } + return ns; + } + + public Expr clone(Object context) + { + int len = path.size(); + LinkedList<Expr> path2 = new LinkedList<Expr>(); + for (int i = 0; i < len; i++) + { + path2.add(path.get(i).clone(context)); + } + return new Steps(path2); + } + + public boolean references(QName var) + { + for (Iterator<Expr> i = path.iterator(); i.hasNext(); ) + { + if (i.next().references(var)) + { + return true; + } + } + return false; + } + + public String toString() + { + CPStringBuilder buf = new CPStringBuilder(); + Iterator<Expr> i = path.iterator(); + Expr expr = i.next(); + if (!(expr instanceof Root)) + { + buf.append(expr); + } + while (i.hasNext()) + { + expr = i.next(); + buf.append('/'); + buf.append(expr); + } + return buf.toString(); + } + +} |