org.apache.commons.lang3.tuple.ImmutableTriple Maven / Gradle / Ivy
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* 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;
/**
* An immutable triple consisting of three {@code 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 triple, then the triple
* itself effectively becomes mutable. The class is also {@code final}, so a subclass
* can not add undesirable behavior.
*
* #ThreadSafe# if all three objects are thread-safe
*
* @param the left element type
* @param the middle element type
* @param the right element type
*
* @since 3.2
*/
public final class ImmutableTriple extends Triple {
/**
* An empty array.
*
* Consider using {@link #emptyArray()} to avoid generics warnings.
*
*
* @since 3.10.
*/
public static final ImmutableTriple[] EMPTY_ARRAY = new ImmutableTriple[0];
/**
* An immutable triple of nulls.
*/
// This is not defined with generics to avoid warnings in call sites.
@SuppressWarnings("rawtypes")
private static final ImmutableTriple NULL = of(null, null, null);
/** Serialization version */
private static final long serialVersionUID = 1L;
/**
* Returns the empty array singleton that can be assigned without compiler warning.
*
* @param the left element type
* @param the middle 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 ImmutableTriple[] emptyArray() {
return (ImmutableTriple[]) EMPTY_ARRAY;
}
/**
* Returns an immutable triple of nulls.
*
* @param the left element of this triple. Value is {@code null}.
* @param the middle element of this triple. Value is {@code null}.
* @param the right element of this triple. Value is {@code null}.
* @return an immutable triple of nulls.
* @since 3.6
*/
public static ImmutableTriple nullTriple() {
return NULL;
}
/**
* Obtains an immutable triple of three objects inferring the generic types.
*
* This factory allows the triple to be created using inference to
* obtain the generic types.
*
* @param the left element type
* @param the middle element type
* @param the right element type
* @param left the left element, may be null
* @param middle the middle element, may be null
* @param right the right element, may be null
* @return a triple formed from the three parameters, not null
*/
public static ImmutableTriple of(final L left, final M middle, final R right) {
return new ImmutableTriple<>(left, middle, right);
}
/** Left object */
public final L left;
/** Middle object */
public final M middle;
/** Right object */
public final R right;
/**
* Create a new triple instance.
*
* @param left the left value, may be null
* @param middle the middle value, may be null
* @param right the right value, may be null
*/
public ImmutableTriple(final L left, final M middle, final R right) {
this.left = left;
this.middle = middle;
this.right = right;
}
//-----------------------------------------------------------------------
/**
* {@inheritDoc}
*/
@Override
public L getLeft() {
return left;
}
/**
* {@inheritDoc}
*/
@Override
public M getMiddle() {
return middle;
}
/**
* {@inheritDoc}
*/
@Override
public R getRight() {
return right;
}
}