| /* |
| * 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.functor.core.composite; |
| |
| import java.io.Serializable; |
| |
| import org.apache.commons.functor.Predicate; |
| import org.apache.commons.functor.Procedure; |
| import org.apache.commons.functor.core.NoOp; |
| import org.apache.commons.lang3.Validate; |
| |
| /** |
| * A {@link Procedure Procedure} |
| * similiar to Java's "ternary" |
| * or "conditional" operator (<code>? :</code>). |
| * Given a {@link Predicate predicate} |
| * <i>p</i> and {@link Procedure procedures} |
| * <i>q</i> and <i>r</i>, {@link #run runs} |
| * <code>if (p.test()) { q.run(); } else { r.run(); }</code>. |
| * <p> |
| * Note that although this class implements |
| * {@link Serializable}, a given instance will |
| * only be truly <code>Serializable</code> if all the |
| * underlying functors are. Attempts to serialize |
| * an instance whose delegates are not all |
| * <code>Serializable</code> will result in an exception. |
| * </p> |
| * @version $Revision$ $Date$ |
| * @author Rodney Waldhoff |
| */ |
| public final class ConditionalProcedure implements Procedure, Serializable { |
| /** |
| * serialVersionUID declaration. |
| */ |
| private static final long serialVersionUID = -4228632798836328605L; |
| |
| /** Base hash integer used to shift hash. */ |
| private static final int HASH_SHIFT = 4; |
| |
| // attributes |
| // ------------------------------------------------------------------------ |
| /** |
| * the condition to be evaluated. |
| */ |
| private final Predicate ifPred; |
| /** |
| * the procedure executed if the condition is satisfied. |
| */ |
| private final Procedure thenProc; |
| /** |
| * the procedure executed if the condition is not satisfied. |
| */ |
| private final Procedure elseProc; |
| |
| // constructor |
| // ------------------------------------------------------------------------ |
| /** |
| * Create a new ConditionalProcedure. |
| * @param ifPred if |
| * @param thenProc then |
| */ |
| public ConditionalProcedure(Predicate ifPred, Procedure thenProc) { |
| this(ifPred, thenProc, NoOp.instance()); |
| } |
| |
| /** |
| * Create a new ConditionalProcedure. |
| * @param ifPred if |
| * @param thenProc then |
| * @param elseProc else |
| */ |
| public ConditionalProcedure(Predicate ifPred, Procedure thenProc, Procedure elseProc) { |
| this.ifPred = Validate.notNull(ifPred, "Predicate argument was null"); |
| this.thenProc = Validate.notNull(thenProc, "'then' Procedure argument was null"); |
| this.elseProc = Validate.notNull(elseProc, "'else' Procedure argument was null"); |
| } |
| |
| // predicate interface |
| // ------------------------------------------------------------------------ |
| /** |
| * {@inheritDoc} |
| */ |
| public void run() { |
| if (ifPred.test()) { |
| thenProc.run(); |
| } else { |
| elseProc.run(); |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean equals(Object that) { |
| return that == this || (that instanceof ConditionalProcedure && equals((ConditionalProcedure) that)); |
| } |
| |
| /** |
| * Learn whether another ConditionalProcecure is equal to this. |
| * @param that the ConditionalProcedure to test |
| * @return boolean |
| */ |
| public boolean equals(ConditionalProcedure that) { |
| return null != that |
| && (null == ifPred ? null == that.ifPred : ifPred.equals(that.ifPred)) |
| && (null == thenProc ? null == that.thenProc : thenProc.equals(that.thenProc)) |
| && (null == elseProc ? null == that.elseProc : elseProc.equals(that.elseProc)); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int hashCode() { |
| int hash = "ConditionalProcedure".hashCode(); |
| if (null != ifPred) { |
| hash <<= HASH_SHIFT; |
| hash ^= ifPred.hashCode(); |
| } |
| if (null != thenProc) { |
| hash <<= HASH_SHIFT; |
| hash ^= thenProc.hashCode(); |
| } |
| if (null != elseProc) { |
| hash <<= HASH_SHIFT; |
| hash ^= elseProc.hashCode(); |
| } |
| return hash; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public String toString() { |
| return "ConditionalProcedure<" + ifPred + "?" + thenProc + ":" + elseProc + ">"; |
| } |
| |
| } |