org.tensorics.core.commons.util.AbstractPair Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of tensorics-core Show documentation

Tensorics is a java framework which uses a tensor as a central object. A tensor represents a set of values placed in an N-dimensional space. Wherever you are tempted to use maps of maps, a tensor might be a good choice ;-) Tensorics provides methods to create, transform and performing calculations with those tensors.

There is a newer version: 0.0.81

Show newest version

// @formatter:off
 /*******************************************************************************
 *
 * This file is part of tensorics.
 * 
 * Copyright (c) 2008-2011, CERN. All rights reserved.
 *
 * Licensed 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.
 * 
 ******************************************************************************/
// @formatter:on

package org.tensorics.core.commons.util;

/**
 * A pair of elements, which is used in several occasion within tensorics calculations, where the values of the same
 * type are commonly used together. The content is named as 'left' and 'right' since very often, the two values might
 * contain operands of binary operations. It provides hashCode and equals methods.
 * 
 * This class is intended to be subclassed. It is highly recommended that the subclasses provide factory methods.
 * 
 * This class does not put any constraint on the consistency of the values. Also {@code null} is allowed for both.
 * Related checks are left to the subclases, if desired.
 * 
 * @param  the type of the elements of the pair
 * @author kfuchsbe
 */
@SuppressWarnings("PMD.CyclomaticComplexity")
public class AbstractPair {

    private final T leftElement;
    private final T rightElement;

    /**
     * A protected class constructor, since instances might only be created using sub classes.
     */
    protected AbstractPair(T leftElement, T rightElement) {
        super();
        this.leftElement = leftElement;
        this.rightElement = rightElement;
    }

    public final T left() {
        return leftElement;
    }

    public final T right() {
        return rightElement;
    }

    @Override
    public final int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((leftElement == null) ? 0 : leftElement.hashCode());
        result = prime * result + ((rightElement == null) ? 0 : rightElement.hashCode());
        return result;
    }

    @Override
    @SuppressWarnings("PMD.CyclomaticComplexity")
    public final boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        AbstractPair other = (AbstractPair) obj;
        if (leftElement == null) {
            if (other.leftElement != null) {
                return false;
            }
        } else if (!leftElement.equals(other.leftElement)) {
            return false;
        }
        if (rightElement == null) {
            if (other.rightElement != null) {
                return false;
            }
        } else if (!rightElement.equals(other.rightElement)) {
            return false;
        }
        return true;
    }
}