harschware.collections.containers.Pair.java Source code

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Here is the source code for harschware.collections.containers.Pair.java

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/**
 * Copyright (C) 2010 Tim Harsch harschware@yahoo.com
 *
 * 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.
 */

package harschware.collections.containers;

import org.apache.commons.lang.builder.CompareToBuilder;

/**
 * Adapted from http://forums.sun.com/thread.jspa?threadID=5132045
 * 
 * 
 * @author harschware
 * 
 * @param <L>
 * @param <R>
 */
public class Pair<L, R> implements Comparable<Object> {

    private final L left;
    private final R right;

    public R getRight() {
        return right;
    } // end getter

    public L getLeft() {
        return left;
    } // end getter

    public Pair(final L left, final R right) {
        this.left = left;
        this.right = right;
    } // end constructor

    public static <A, B> Pair<A, B> create(A left, B right) {
        return new Pair<A, B>(left, right);
    } // end factory method

    @Override
    public final boolean equals(Object o) {
        if (!(o instanceof Pair<?, ?>))
            return false;

        final Pair<?, ?> other = (Pair<?, ?>) o;
        return equal(getLeft(), other.getLeft()) && equal(getRight(), other.getRight());
    } // end method

    public static final boolean equal(Object o1, Object o2) {
        if (o1 == null) {
            return o2 == null;
        }
        return o1.equals(o2);
    } // end method

    @Override
    public int hashCode() {
        int hLeft = getLeft() == null ? 0 : getLeft().hashCode();
        int hRight = getRight() == null ? 0 : getRight().hashCode();

        return hLeft + (37 * hRight);
    } // end method

    public int compareTo(Object o) {
        Pair<?, ?> other = (Pair<?, ?>) o;
        return new CompareToBuilder().append(this.left, other.left).append(this.right, other.right).toComparison();
    } // end method

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append('<');
        if (left == null) {
            sb.append("null");
        } else {
            sb.append(left.toString());
        } // end if
        sb.append(',');
        if (right == null) {
            sb.append("null");
        } else {
            sb.append(right.toString());
        } // end if
        sb.append('>');
        return sb.toString();
    } // end method
} // end class