1 files changed, 130 insertions, 0 deletions
diff --git a/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/util/IdentityStack.java b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/util/IdentityStack.java
new file mode 100644
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+++ b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/util/IdentityStack.java
@@ -0,0 +1,130 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+package org.apache.tools.ant.util;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.IdentityHashMap;
+import java.util.Set;
+import java.util.Stack;
+
+/**
+ * Identity Stack.
+ * @since Ant 1.7
+ */
+public class IdentityStack<E> extends Stack<E> {
+
+    private static final long serialVersionUID = -5555522620060077046L;
+
+    /**
+     * Get an IdentityStack containing the contents of the specified Stack.
+     * @param s the Stack to copy; ignored if null.
+     * @return an IdentityStack instance.
+     */
+    public static <E> IdentityStack<E> getInstance(Stack<E> s) {
+        if (s instanceof IdentityStack) {
+            return (IdentityStack<E>) s;
+        }
+        IdentityStack<E> result = new IdentityStack<E>();
+        if (s != null) {
+            result.addAll(s);
+        }
+        return result;
+    }
+
+    /**
+     * Default constructor.
+     */
+    public IdentityStack() {
+    }
+
+    /**
+     * Construct a new IdentityStack with the specified Object
+     * as the bottom element.
+     * @param o the bottom element.
+     */
+    public IdentityStack(E o) {
+        super();
+        push(o);
+    }
+
+    /**
+     * Override methods that use <code>.equals()</code> comparisons on elements.
+     * @param o the Object to search for.
+     * @return true if the stack contains the object.
+     * @see java.util.Vector#contains(Object)
+     */
+    public synchronized boolean contains(Object o) {
+        return indexOf(o) >= 0;
+    }
+
+    /**
+     * Override methods that use <code>.equals()</code> comparisons on elements.
+     * @param o   the Object to search for.
+     * @param pos the position from which to search.
+     * @return the position of the object, -1 if not found.
+     * @see java.util.Vector#indexOf(Object, int)
+     */
+    public synchronized int indexOf(Object o, int pos) {
+        final int size = size();
+        for (int i = pos; i < size; i++) {
+            if (get(i) == o) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    /**
+     * Override methods that use <code>.equals()</code> comparisons on elements.
+     * @param o   the Object to search for.
+     * @param pos the position from which to search (backward).
+     * @return the position of the object, -1 if not found.
+     * @see java.util.Vector#indexOf(Object, int)
+     */
+    public synchronized int lastIndexOf(Object o, int pos) {
+        for (int i = pos; i >= 0; i--) {
+            if (get(i) == o) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    public synchronized boolean removeAll(Collection<?> c) {
+        if (!(c instanceof Set)) {
+            c = new HashSet(c);
+        }
+        return super.removeAll(c);
+    }
+
+    public synchronized boolean retainAll(Collection c) {
+        if (!(c instanceof Set)) {
+            c = new HashSet(c);
+        }
+        return super.retainAll(c);
+    }
+
+    public synchronized boolean containsAll(Collection<?> c) {
+        IdentityHashMap map = new IdentityHashMap();
+        for (Object e : this) {
+            map.put(e, Boolean.TRUE);
+        }
+        return map.keySet().containsAll(c);
+    }
+}