001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.functor.adapter;
018
019import java.io.Serializable;
020
021import org.apache.commons.functor.BinaryProcedure;
022import org.apache.commons.functor.Procedure;
023import org.apache.commons.lang3.Validate;
024
025/**
026 * Adapts a
027 * {@link BinaryProcedure BinaryProcedure}
028 * to the
029 * {@link Procedure Procedure} interface
030 * using a constant left-side argument.
031 * <p/>
032 * Note that although this class implements
033 * {@link Serializable}, a given instance will
034 * only be truly <code>Serializable</code> if the
035 * underlying objects are.  Attempts to serialize
036 * an instance whose delegates are not
037 * <code>Serializable</code> will result in an exception.
038 *
039 * @version $Revision: 1365377 $ $Date: 2012-07-24 20:59:23 -0400 (Tue, 24 Jul 2012) $
040 */
041public final class FullyBoundProcedure implements Procedure, Serializable {
042    /**
043     * serialVersionUID declaration.
044     */
045    private static final long serialVersionUID = -904891610081737737L;
046    /** The {@link BinaryProcedure BinaryProcedure} I'm wrapping. */
047    private final BinaryProcedure<Object, Object> procedure;
048    /** The left parameter to pass to {@code procedure}. */
049    private final Object left;
050    /** The right parameter to pass to {@code procedure}. */
051    private final Object right;
052
053    /**
054     * Create a new FullyBoundProcedure instance.
055     * @param <L> left type
056     * @param <R> right type
057     * @param procedure the procedure to adapt
058     * @param left the left argument to use
059     * @param right the right argument to use
060     */
061    @SuppressWarnings("unchecked")
062    public <L, R> FullyBoundProcedure(BinaryProcedure<? super L, ? super R> procedure, L left, R right) {
063        this.procedure =
064            (BinaryProcedure<Object, Object>) Validate.notNull(procedure,
065                "BinaryProcedure argument was null");
066        this.left = left;
067        this.right = right;
068    }
069
070    /**
071     * {@inheritDoc}
072     */
073    public void run() {
074        procedure.run(left, right);
075    }
076
077    /**
078     * {@inheritDoc}
079     */
080    @Override
081    public boolean equals(Object that) {
082        return that == this || (that instanceof FullyBoundProcedure && equals((FullyBoundProcedure) that));
083    }
084
085    /**
086     * Learn whether another FullyBoundProcedure is equal to this.
087     * @param that FullyBoundProcedure to test
088     * @return boolean
089     */
090    public boolean equals(FullyBoundProcedure that) {
091        return null != that && procedure.equals(that.procedure)
092                && (null == left ? null == that.left : left.equals(that.left))
093                && (null == right ? null == that.right : right.equals(that.right));
094    }
095
096    /**
097     * {@inheritDoc}
098     */
099    @Override
100    public int hashCode() {
101        int hash = "FullyBoundProcedure".hashCode();
102        hash <<= 2;
103        hash ^= procedure.hashCode();
104        hash <<= 2;
105        if (null != left) {
106            hash ^= left.hashCode();
107        }
108        hash <<= 2;
109        if (null != right) {
110            hash ^= right.hashCode();
111        }
112        return hash;
113    }
114
115    /**
116     * {@inheritDoc}
117     */
118    @Override
119    public String toString() {
120        return "FullyBoundProcedure<" + procedure + "(" + left + ", " + right + ")>";
121    }
122
123    /**
124     * Adapt a BinaryProcedure to the Procedure interface.
125     * @param <L> left type
126     * @param <R> right type
127     * @param procedure to adapt
128     * @param left left side argument
129     * @param right right side argument
130     * @return FullyBoundProcedure
131     */
132    public static <L, R> FullyBoundProcedure bind(BinaryProcedure<? super L, ? super R> procedure, L left, R right) {
133        return null == procedure ? null : new FullyBoundProcedure(procedure, left, right);
134    }
135
136}