All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.apache.commons.lang3.tuple.ImmutablePair Maven / Gradle / Ivy

There is a newer version: 4.1.4
Show newest version
/*
 * 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.commons.lang3.tuple;

import java.util.Map;
import java.util.Objects;

/**
 * An immutable pair consisting of two {@link Object} elements.
 *
 * 

Although the implementation is immutable, there is no restriction on the objects * that may be stored. If mutable objects are stored in the pair, then the pair * itself effectively becomes mutable. The class is also {@code final}, so a subclass * can not add undesirable behavior.

* *

#ThreadSafe# if both paired objects are thread-safe

* * @param the left element type * @param the right element type * * @since 3.0 */ public class ImmutablePair extends Pair { /** * An empty array. *

* Consider using {@link #emptyArray()} to avoid generics warnings. *

* * @since 3.10. */ public static final ImmutablePair[] EMPTY_ARRAY = {}; /** * An immutable pair of nulls. */ // This is not defined with generics to avoid warnings in call sites. @SuppressWarnings("rawtypes") private static final ImmutablePair NULL = new ImmutablePair<>(null, null); /** Serialization version */ private static final long serialVersionUID = 4954918890077093841L; /** * Returns the empty array singleton that can be assigned without compiler warning. * * @param the left element type * @param the right element type * @return the empty array singleton that can be assigned without compiler warning. * * @since 3.10. */ @SuppressWarnings("unchecked") public static ImmutablePair[] emptyArray() { return (ImmutablePair[]) EMPTY_ARRAY; } /** * Creates an immutable pair of two objects inferring the generic types. * *

This factory allows the pair to be created using inference to * obtain the generic types.

* * @param the left element type * @param the right element type * @param left the left element, may be null * @return a pair formed from the two parameters, not null * @since 3.11 */ public static Pair left(final L left) { return ImmutablePair.of(left, null); } /** * Returns an immutable pair of nulls. * * @param the left element of this pair. Value is {@code null}. * @param the right element of this pair. Value is {@code null}. * @return an immutable pair of nulls. * @since 3.6 */ @SuppressWarnings("unchecked") public static ImmutablePair nullPair() { return NULL; } /** * Creates an immutable pair of two objects inferring the generic types. * *

This factory allows the pair to be created using inference to * obtain the generic types.

* * @param the left element type * @param the right element type * @param left the left element, may be null * @param right the right element, may be null * @return a pair formed from the two parameters, not null */ public static ImmutablePair of(final L left, final R right) { return left != null || right != null ? new ImmutablePair<>(left, right) : nullPair(); } /** * Creates an immutable pair from a map entry. * *

This factory allows the pair to be created using inference to * obtain the generic types.

* * @param the left element type * @param the right element type * @param pair the existing map entry. * @return a pair formed from the map entry * @since 3.10 */ public static ImmutablePair of(final Map.Entry pair) { return pair != null ? new ImmutablePair<>(pair.getKey(), pair.getValue()) : nullPair(); } /** * Creates an immutable pair of two non-null objects inferring the generic types. * *

This factory allows the pair to be created using inference to * obtain the generic types.

* * @param the left element type * @param the right element type * @param left the left element, may not be null * @param right the right element, may not be null * @return a pair formed from the two parameters, not null * @throws NullPointerException if any input is null * @since 3.13.0 */ public static ImmutablePair ofNonNull(final L left, final R right) { return of(Objects.requireNonNull(left, "left"), Objects.requireNonNull(right, "right")); } /** * Creates an immutable pair of two objects inferring the generic types. * *

This factory allows the pair to be created using inference to * obtain the generic types.

* * @param the left element type * @param the right element type * @param right the right element, may be null * @return a pair formed from the two parameters, not null * @since 3.11 */ public static Pair right(final R right) { return ImmutablePair.of(null, right); } /** Left object */ public final L left; /** Right object */ public final R right; /** * Create a new pair instance. * * @param left the left value, may be null * @param right the right value, may be null */ public ImmutablePair(final L left, final R right) { this.left = left; this.right = right; } /** * {@inheritDoc} */ @Override public L getLeft() { return left; } /** * {@inheritDoc} */ @Override public R getRight() { return right; } /** * Throws {@link UnsupportedOperationException}. * *

This pair is immutable, so this operation is not supported.

* * @param value the value to set * @return never * @throws UnsupportedOperationException as this operation is not supported */ @Override public R setValue(final R value) { throw new UnsupportedOperationException(); } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy