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java/org/apache/catalina/util/ResourceSet.java

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+/*
+ * 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.catalina.util;
+
+
+import java.util.Collection;
+import java.util.HashSet;
+
+import org.apache.tomcat.util.res.StringManager;
+
+
+/**
+ * Extended implementation of <strong>HashSet</strong> that includes a
+ * <code>locked</code> property.  This class can be used to safely expose
+ * resource path sets to user classes without having to clone them in order
+ * to avoid modifications.  When first created, a <code>ResourceMap</code>
+ * is not locked.
+ *
+ * @param <T> The type of elements in the Set
+ *
+ * @author Craig R. McClanahan
+ */
+public final class ResourceSet<T> extends HashSet<T> {
+
+    private static final long serialVersionUID = 1L;
+
+    // ----------------------------------------------------------- Constructors
+    /**
+     * Construct a new, empty set with the default initial capacity and
+     * load factor.
+     */
+    public ResourceSet() {
+
+        super();
+
+    }
+
+
+    /**
+     * Construct a new, empty set with the specified initial capacity and
+     * default load factor.
+     *
+     * @param initialCapacity The initial capacity of this set
+     */
+    public ResourceSet(int initialCapacity) {
+
+        super(initialCapacity);
+
+    }
+
+
+    /**
+     * Construct a new, empty set with the specified initial capacity and
+     * load factor.
+     *
+     * @param initialCapacity The initial capacity of this set
+     * @param loadFactor The load factor of this set
+     */
+    public ResourceSet(int initialCapacity, float loadFactor) {
+
+        super(initialCapacity, loadFactor);
+
+    }
+
+
+    /**
+     * Construct a new set with the same contents as the existing collection.
+     *
+     * @param coll The collection whose contents we should copy
+     */
+    public ResourceSet(Collection<T> coll) {
+
+        super(coll);
+
+    }
+
+
+    // ------------------------------------------------------------- Properties
+
+
+    /**
+     * The current lock state of this parameter map.
+     */
+    private boolean locked = false;
+
+
+    /**
+     * @return the locked state of this parameter map.
+     */
+    public boolean isLocked() {
+        return this.locked;
+    }
+
+
+    /**
+     * Set the locked state of this parameter map.
+     *
+     * @param locked The new locked state
+     */
+    public void setLocked(boolean locked) {
+        this.locked = locked;
+    }
+
+
+    /**
+     * The string manager for this package.
+     */
+    private static final StringManager sm =
+        StringManager.getManager("org.apache.catalina.util");
+
+
+    // --------------------------------------------------------- Public Methods
+
+
+    /**
+     * Add the specified element to this set if it is not already present.
+     * Return <code>true</code> if the element was added.
+     *
+     * @param o The object to be added
+     *
+     * @exception IllegalStateException if this ResourceSet is locked
+     */
+    @Override
+    public boolean add(T o) {
+        if (locked)
+            throw new IllegalStateException
+              (sm.getString("resourceSet.locked"));
+        return super.add(o);
+    }
+
+
+    /**
+     * Remove all of the elements from this set.
+     *
+     * @exception IllegalStateException if this ResourceSet is locked
+     */
+    @Override
+    public void clear() {
+
+        if (locked)
+            throw new IllegalStateException
+              (sm.getString("resourceSet.locked"));
+        super.clear();
+
+    }
+
+
+    /**
+     * Remove the given element from this set if it is present.
+     * Return <code>true</code> if the element was removed.
+     *
+     * @param o The object to be removed
+     *
+     * @exception IllegalStateException if this ResourceSet is locked
+     */
+    @Override
+    public boolean remove(Object o) {
+        if (locked)
+            throw new IllegalStateException
+              (sm.getString("resourceSet.locked"));
+        return super.remove(o);
+    }
+
+
+}