001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.keyvalue;
018
019import java.util.Map;
020
021import org.apache.commons.collections4.KeyValue;
022import org.apache.commons.collections4.Unmodifiable;
023
024/**
025 * A {@link java.util.Map.Entry Map.Entry} that throws
026 * UnsupportedOperationException when <code>setValue</code> is called.
027 *
028 * @since 3.0
029 */
030public final class UnmodifiableMapEntry<K, V> extends AbstractMapEntry<K, V> implements Unmodifiable {
031
032    /**
033     * Constructs a new entry with the specified key and given value.
034     *
035     * @param key  the key for the entry, may be null
036     * @param value  the value for the entry, may be null
037     */
038    public UnmodifiableMapEntry(final K key, final V value) {
039        super(key, value);
040    }
041
042    /**
043     * Constructs a new entry from the specified <code>KeyValue</code>.
044     *
045     * @param pair  the pair to copy, must not be null
046     * @throws NullPointerException if the entry is null
047     */
048    public UnmodifiableMapEntry(final KeyValue<? extends K, ? extends V> pair) {
049        super(pair.getKey(), pair.getValue());
050    }
051
052    /**
053     * Constructs a new entry from the specified <code>Map.Entry</code>.
054     *
055     * @param entry  the entry to copy, must not be null
056     * @throws NullPointerException if the entry is null
057     */
058    public UnmodifiableMapEntry(final Map.Entry<? extends K, ? extends V> entry) {
059        super(entry.getKey(), entry.getValue());
060    }
061
062    /**
063     * Throws UnsupportedOperationException.
064     *
065     * @param value  the new value
066     * @return the previous value
067     * @throws UnsupportedOperationException always
068     */
069    @Override
070    public V setValue(final V value) {
071        throw new UnsupportedOperationException("setValue() is not supported");
072    }
073
074}