1 files changed, 135 insertions, 0 deletions
diff --git a/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/FailFast.java b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/FailFast.java
new file mode 100644
index 00000000..dc962bb4
--- /dev/null
+++ b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/FailFast.java
@@ -0,0 +1,135 @@
+/*
+ *  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.types.resources;
+
+import java.util.ConcurrentModificationException;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import java.util.WeakHashMap;
+
+import org.apache.tools.ant.types.Resource;
+
+/**
+ * Helper class for ResourceCollections to return Iterators
+ * that fail on changes to the object.
+ * @since Ant 1.7
+ */
+/*package-private*/ class FailFast implements Iterator<Resource> {
+    private static final WeakHashMap<Object, Set<FailFast>> MAP = new WeakHashMap<Object, Set<FailFast>>();
+
+    /**
+     * Invalidate any in-use Iterators from the specified Object.
+     * @param o the parent Object.
+     */
+    static synchronized void invalidate(Object o) {
+        Set<FailFast> s = MAP.get(o);
+        if (s != null) {
+            s.clear();
+        }
+    }
+
+    private static synchronized void add(FailFast f) {
+        Set<FailFast> s = MAP.get(f.parent);
+        if (s == null) {
+            s = new HashSet<FailFast>();
+            MAP.put(f.parent, s);
+        }
+        s.add(f);
+    }
+
+    private static synchronized void remove(FailFast f) {
+        Set<FailFast> s = MAP.get(f.parent);
+        if (s != null) {
+            s.remove(f);
+        }
+    }
+
+    private static synchronized void failFast(FailFast f) {
+        Set<FailFast> s = MAP.get(f.parent);
+        if (!s.contains(f)) {
+            throw new ConcurrentModificationException();
+        }
+    }
+
+    private final Object parent;
+    private Iterator<Resource> wrapped;
+
+    /**
+     * Construct a new FailFast Iterator wrapping the specified Iterator
+     * and dependent upon the specified parent Object.
+     * @param o the parent Object.
+     * @param i the wrapped Iterator.
+     */
+    FailFast(Object o, Iterator<Resource> i) {
+        if (o == null) {
+            throw new IllegalArgumentException("parent object is null");
+        }
+        if (i == null) {
+            throw new IllegalArgumentException("cannot wrap null iterator");
+        }
+        parent = o;
+        if (i.hasNext()) {
+            wrapped = i;
+            add(this);
+        }
+    }
+
+    /**
+     * Fulfill the Iterator contract.
+     * @return true if there are more elements.
+     */
+    public boolean hasNext() {
+        if (wrapped == null) {
+            return false;
+        }
+        failFast(this);
+        return wrapped.hasNext();
+    }
+
+    /**
+     * Fulfill the Iterator contract.
+     * @return the next element.
+     * @throws NoSuchElementException if no more elements.
+     */
+    public Resource next() {
+        if (wrapped == null || !wrapped.hasNext()) {
+            throw new NoSuchElementException();
+        }
+        failFast(this);
+        try {
+            return wrapped.next();
+        } finally {
+            if (!wrapped.hasNext()) {
+                wrapped = null;
+                remove(this);
+            }
+        }
+    }
+
+    /**
+     * Fulfill the Iterator contract.
+     * @throws UnsupportedOperationException always.
+     */
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+
+}
+