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java/org/apache/catalina/util/ParameterMap.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.io.Serializable;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.tomcat.util.res.StringManager;
+
+/**
+ * Implementation of <strong>java.util.Map</strong> that includes a
+ * <code>locked</code> property.  This class can be used to safely expose
+ * Catalina internal parameter map objects to user classes without having
+ * to clone them in order to avoid modifications.  When first created, a
+ * <code>ParmaeterMap</code> instance is not locked.
+ *
+ * @param <K> The type of Key
+ * @param <V> The type of Value
+ *
+ * @author Craig R. McClanahan
+ */
+public final class ParameterMap<K,V> implements Map<K,V>, Serializable {
+
+    private static final long serialVersionUID = 2L;
+
+    private final Map<K,V> delegatedMap;
+
+    private final Map<K,V> unmodifiableDelegatedMap;
+
+
+    /**
+     * Construct a new, empty map with the default initial capacity and
+     * load factor.
+     */
+    public ParameterMap() {
+        delegatedMap = new LinkedHashMap<>();
+        unmodifiableDelegatedMap = Collections.unmodifiableMap(delegatedMap);
+    }
+
+
+    /**
+     * Construct a new, empty map with the specified initial capacity and
+     * default load factor.
+     *
+     * @param initialCapacity The initial capacity of this map
+     */
+    public ParameterMap(int initialCapacity) {
+        delegatedMap = new LinkedHashMap<>(initialCapacity);
+        unmodifiableDelegatedMap = Collections.unmodifiableMap(delegatedMap);
+    }
+
+
+    /**
+     * Construct a new, empty map with the specified initial capacity and
+     * load factor.
+     *
+     * @param initialCapacity The initial capacity of this map
+     * @param loadFactor The load factor of this map
+     */
+    public ParameterMap(int initialCapacity, float loadFactor) {
+        delegatedMap = new LinkedHashMap<>(initialCapacity, loadFactor);
+        unmodifiableDelegatedMap = Collections.unmodifiableMap(delegatedMap);
+    }
+
+
+    /**
+     * Construct a new map with the same mappings as the given map.
+     *
+     * @param map Map whose contents are duplicated in the new map
+     */
+    public ParameterMap(Map<K,V> map) {
+        delegatedMap = new LinkedHashMap<>(map);
+        unmodifiableDelegatedMap = Collections.unmodifiableMap(delegatedMap);
+    }
+
+
+    /**
+     * The current lock state of this parameter map.
+     */
+    private boolean locked = false;
+
+
+    /**
+     * @return the locked state of this parameter map.
+     */
+    public boolean isLocked() {
+        return 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");
+
+
+    /**
+     * {@inheritDoc}
+     *
+     * @exception IllegalStateException if this map is currently locked
+     */
+    @Override
+    public void clear() {
+        checkLocked();
+        delegatedMap.clear();
+    }
+
+
+    /**
+     * {@inheritDoc}
+     *
+     * @exception IllegalStateException if this map is currently locked
+     */
+    @Override
+    public V put(K key, V value) {
+        checkLocked();
+        return delegatedMap.put(key, value);
+    }
+
+
+    /**
+     * {@inheritDoc}
+     *
+     * @exception IllegalStateException if this map is currently locked
+     */
+    @Override
+    public void putAll(Map<? extends K,? extends V> map) {
+        checkLocked();
+        delegatedMap.putAll(map);
+    }
+
+
+    /**
+     * {@inheritDoc}
+     *
+     * @exception IllegalStateException if this map is currently locked
+     */
+    @Override
+    public V remove(Object key) {
+        checkLocked();
+        return delegatedMap.remove(key);
+    }
+
+
+    private void checkLocked() {
+        if (locked) {
+            throw new IllegalStateException(sm.getString("parameterMap.locked"));
+        }
+    }
+
+
+    @Override
+    public int size() {
+        return delegatedMap.size();
+    }
+
+
+    @Override
+    public boolean isEmpty() {
+        return delegatedMap.isEmpty();
+    }
+
+
+    @Override
+    public boolean containsKey(Object key) {
+        return delegatedMap.containsKey(key);
+    }
+
+
+    @Override
+    public boolean containsValue(Object value) {
+        return delegatedMap.containsValue(value);
+    }
+
+
+    @Override
+    public V get(Object key) {
+        return delegatedMap.get(key);
+    }
+
+
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Returns an <strong>unmodifiable</strong> {@link Set} view of the keys
+     * contained in this map if it is locked.
+     */
+    @Override
+    public Set<K> keySet() {
+        if (locked) {
+            return unmodifiableDelegatedMap.keySet();
+        }
+
+        return delegatedMap.keySet();
+    }
+
+
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Returns an <strong>unmodifiable</strong> {@link Collection} view of the
+     * values contained in this map if it is locked.
+     */
+    @Override
+    public Collection<V> values() {
+        if (locked) {
+            return unmodifiableDelegatedMap.values();
+        }
+
+        return delegatedMap.values();
+    }
+
+
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Returns an <strong>unmodifiable</strong> {@link Set} view of the mappings
+     * contained in this map if it is locked.
+     */
+    @Override
+    public Set<java.util.Map.Entry<K, V>> entrySet() {
+        if (locked) {
+            return unmodifiableDelegatedMap.entrySet();
+        }
+
+        return delegatedMap.entrySet();
+    }
+}