/*
 * 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
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package org.apache.commons.collections4.keyvalue;

import java.util.Map;

import org.apache.commons.collections4.KeyValue;

A mutable KeyValue pair that does not implement Map.Entry.

Note that a DefaultKeyValue instance may not contain itself as a key or value.

Since:3.0
/** * A mutable <code>KeyValue</code> pair that does not implement * {@link java.util.Map.Entry Map.Entry}. * <p> * Note that a <code>DefaultKeyValue</code> instance may not contain * itself as a key or value. * * @since 3.0 */
public class DefaultKeyValue<K, V> extends AbstractKeyValue<K, V> {
Constructs a new pair with a null key and null value.
/** * Constructs a new pair with a null key and null value. */
public DefaultKeyValue() { super(null, null); }
Constructs a new pair with the specified key and given value.
Params:
  • key – the key for the entry, may be null
  • value – the value for the entry, may be null
/** * Constructs a new pair with the specified key and given value. * * @param key the key for the entry, may be null * @param value the value for the entry, may be null */
public DefaultKeyValue(final K key, final V value) { super(key, value); }
Constructs a new pair from the specified KeyValue.
Params:
  • pair – the pair to copy, must not be null
Throws:
/** * Constructs a new pair from the specified <code>KeyValue</code>. * * @param pair the pair to copy, must not be null * @throws NullPointerException if the entry is null */
public DefaultKeyValue(final KeyValue<? extends K, ? extends V> pair) { super(pair.getKey(), pair.getValue()); }
Constructs a new pair from the specified Map.Entry.
Params:
  • entry – the entry to copy, must not be null
Throws:
/** * Constructs a new pair from the specified <code>Map.Entry</code>. * * @param entry the entry to copy, must not be null * @throws NullPointerException if the entry is null */
public DefaultKeyValue(final Map.Entry<? extends K, ? extends V> entry) { super(entry.getKey(), entry.getValue()); } //-----------------------------------------------------------------------
Sets the key.
Params:
  • key – the new key
Throws:
Returns:the old key
/** * Sets the key. * * @param key the new key * @return the old key * @throws IllegalArgumentException if key is this object */
@Override public K setKey(final K key) { if (key == this) { throw new IllegalArgumentException("DefaultKeyValue may not contain itself as a key."); } return super.setKey(key); }
Sets the value.
Params:
  • value – the new value
Throws:
Returns:the old value of the value
/** * Sets the value. * * @return the old value of the value * @param value the new value * @throws IllegalArgumentException if value is this object */
@Override public V setValue(final V value) { if (value == this) { throw new IllegalArgumentException("DefaultKeyValue may not contain itself as a value."); } return super.setValue(value); } //-----------------------------------------------------------------------
Returns a new Map.Entry object with key and value from this pair.
Returns:a MapEntry instance
/** * Returns a new <code>Map.Entry</code> object with key and value from this pair. * * @return a MapEntry instance */
public Map.Entry<K, V> toMapEntry() { return new DefaultMapEntry<>(this); } //-----------------------------------------------------------------------
Compares this Map.Entry with another Map.Entry.

Returns true if the compared object is also a DefaultKeyValue, and its key and value are equal to this object's key and value.

Params:
  • obj – the object to compare to
Returns:true if equal key and value
/** * Compares this <code>Map.Entry</code> with another <code>Map.Entry</code>. * <p> * Returns true if the compared object is also a <code>DefaultKeyValue</code>, * and its key and value are equal to this object's key and value. * * @param obj the object to compare to * @return true if equal key and value */
@Override public boolean equals(final Object obj) { if (obj == this) { return true; } if (obj instanceof DefaultKeyValue == false) { return false; } final DefaultKeyValue<?, ?> other = (DefaultKeyValue<?, ?>) obj; return (getKey() == null ? other.getKey() == null : getKey().equals(other.getKey())) && (getValue() == null ? other.getValue() == null : getValue().equals(other.getValue())); }
Gets a hashCode compatible with the equals method.

Implemented per API documentation of Entry.hashCode(), however subclasses may override this.

Returns:a suitable hash code
/** * Gets a hashCode compatible with the equals method. * <p> * Implemented per API documentation of {@link java.util.Map.Entry#hashCode()}, * however subclasses may override this. * * @return a suitable hash code */
@Override public int hashCode() { return (getKey() == null ? 0 : getKey().hashCode()) ^ (getValue() == null ? 0 : getValue().hashCode()); } }