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 *      https://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;
020import java.util.Map.Entry;
021
022import org.apache.commons.collections4.KeyValue;
023import org.apache.commons.collections4.Unmodifiable;
024
025/**
026 * A {@link Entry Map.Entry} that throws
027 * UnsupportedOperationException when {@code setValue} is called.
028 *
029 * @param <K> The type of keys
030 * @param <V> The type of mapped values
031 * @since 3.0
032 */
033public final class UnmodifiableMapEntry<K, V> extends AbstractMapEntry<K, V> implements Unmodifiable {
034
035    /**
036     * Constructs a new entry with the specified key and given value.
037     *
038     * @param key  The key for the entry, may be null
039     * @param value  The value for the entry, may be null
040     */
041    public UnmodifiableMapEntry(final K key, final V value) {
042        super(key, value);
043    }
044
045    /**
046     * Constructs a new entry from the specified {@code KeyValue}.
047     *
048     * @param pair  The pair to copy, must not be null
049     * @throws NullPointerException if the entry is null
050     */
051    public UnmodifiableMapEntry(final KeyValue<? extends K, ? extends V> pair) {
052        super(pair.getKey(), pair.getValue());
053    }
054
055    /**
056     * Constructs a new entry from the specified {@code Map.Entry}.
057     *
058     * @param entry  The entry to copy, must not be null
059     * @throws NullPointerException if the entry is null
060     */
061    public UnmodifiableMapEntry(final Map.Entry<? extends K, ? extends V> entry) {
062        super(entry.getKey(), entry.getValue());
063    }
064
065    /**
066     * Throws UnsupportedOperationException.
067     *
068     * @param value  The new value
069     * @return The previous value
070     * @throws UnsupportedOperationException always
071     */
072    @Override
073    public V setValue(final V value) {
074        throw new UnsupportedOperationException("setValue() is not supported");
075    }
076
077}