    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} is called.
    027 *
    028 * @param <K> the type of keys
    029 * @param <V> the type of mapped values
    030 * @since 3.0
    031 */
    032public final class UnmodifiableMapEntry<K, V> extends AbstractMapEntry<K, V> implements Unmodifiable {
    033
    034    /**
    035     * Constructs a new entry with the specified key and given value.
    036     *
    037     * @param key  the key for the entry, may be null
    038     * @param value  the value for the entry, may be null
    039     */
    040    public UnmodifiableMapEntry(final K key, final V value) {
    041        super(key, value);
    042    }
    043
    044    /**
    045     * Constructs a new entry from the specified {@code KeyValue}.
    046     *
    047     * @param pair  the pair to copy, must not be null
    048     * @throws NullPointerException if the entry is null
    049     */
    050    public UnmodifiableMapEntry(final KeyValue<? extends K, ? extends V> pair) {
    051        super(pair.getKey(), pair.getValue());
    052    }
    053
    054    /**
    055     * Constructs a new entry from the specified {@code Map.Entry}.
    056     *
    057     * @param entry  the entry to copy, must not be null
    058     * @throws NullPointerException if the entry is null
    059     */
    060    public UnmodifiableMapEntry(final Map.Entry<? extends K, ? extends V> entry) {
    061        super(entry.getKey(), entry.getValue());
    062    }
    063
    064    /**
    065     * Throws UnsupportedOperationException.
    066     *
    067     * @param value  the new value
    068     * @return the previous value
    069     * @throws UnsupportedOperationException always
    070     */
    071    @Override
    072    public V setValue(final V value) {
    073        throw new UnsupportedOperationException("setValue() is not supported");
    074    }
    075
    076}