summaryrefslogtreecommitdiff
path: root/libjava/classpath/java/beans/Expression.java
diff options
context:
space:
mode:
authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/beans/Expression.java
downloadcbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.bz2
cbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.xz
obtained gcc-4.6.4.tar.bz2 from upstream website;upstream
verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository.
Diffstat (limited to 'libjava/classpath/java/beans/Expression.java')
-rw-r--r--libjava/classpath/java/beans/Expression.java138
1 files changed, 138 insertions, 0 deletions
diff --git a/libjava/classpath/java/beans/Expression.java b/libjava/classpath/java/beans/Expression.java
new file mode 100644
index 000000000..d07c28b4a
--- /dev/null
+++ b/libjava/classpath/java/beans/Expression.java
@@ -0,0 +1,138 @@
+/* java.beans.Expression
+ Copyright (C) 2004, 2005 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 java.beans;
+
+/**
+ * <p>An Expression captures the execution of an object method
+ * that returns a value.</p>
+ *
+ * <p>It stores an object, the method to call, and the arguments to pass to
+ * the method.</p>
+ *
+ * <p>While this class can generally be used to describe method calls it is
+ * part of the XML serialization API.</p>
+ *
+ * @author Robert Schuster (robertschuster@fsfe.org)
+ * @since 1.4
+ */
+public class Expression extends Statement
+{
+ // This is a placeholder to indicate that value hasn't been set
+ // yet;
+ private static final Object UNSET = new Object();
+
+ // The value to return. This is equal to unset until getValue is called.
+ private Object value;
+
+ /**
+ * Constructor Constructs an Expression representing the invocation of
+ * object.methodName(arg[0], arg[1], ...); However, it will never be executed.
+ * Instead, value will always be returned.
+ *
+ * @param value
+ * The value to return.
+ * @param target
+ * The object to invoke the method on.
+ * @param methodName
+ * The object method to invoke.
+ * @param arguments
+ * An array of arguments to pass to the method.
+ */
+ public Expression(Object value, Object target, String methodName,
+ Object[] arguments)
+ {
+ super(target, methodName, arguments);
+ this.value = value;
+ }
+
+ /**
+ * Constructor Constructs an Expression representing the invocation of
+ * object.methodName(arg[0], arg[1], ...);
+ *
+ * @param target
+ * The object to invoke the method on.
+ * @param methodName
+ * The object method to invoke.
+ * @param arguments
+ * An array of arguments to pass to the method.
+ */
+ public Expression(Object target, String methodName, Object[] arguments)
+ {
+ super(target, methodName, arguments);
+ this.value = UNSET;
+ }
+
+ /**
+ * Return the result of executing the method. If the cached value has not yet
+ * been set, the method is executed in the same way as Statement.execute(),
+ * except that the value is cached, and then returned. If the value has been
+ * set, it is returned without executing the method again.
+ *
+ * @return the result of executing the method.
+ * @exception Exception
+ * if an error occurs
+ */
+ public Object getValue() throws Exception
+ {
+ if (value == UNSET)
+ value = doExecute();
+ return value;
+ }
+
+ /**
+ * Set the cached value to be returned by getValue()
+ *
+ * @param value
+ * the value to cache and return.
+ */
+ public void setValue(Object value)
+ {
+ this.value = value;
+ }
+
+ /**
+ * Return a string representation of this expression.
+ */
+ public String toString()
+ {
+ String result = super.toString();
+ if (value != UNSET)
+ return value.getClass().getName() + "=" + result;
+ return result;
+ }
+}