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 */
017 package org.apache.commons.collections.functors;
018
019 import java.io.Serializable;
020
021 import org.apache.commons.collections.Closure;
022
023 /**
024 * Closure implementation that calls another closure n times, like a for loop.
025 *
026 * @since Commons Collections 3.0
027 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
028 *
029 * @author Stephen Colebourne
030 */
031 public class ForClosure implements Closure, Serializable {
032
033 /** Serial version UID */
034 private static final long serialVersionUID = -1190120533393621674L;
035
036 /** The number of times to loop */
037 private final int iCount;
038 /** The closure to call */
039 private final Closure iClosure;
040
041 /**
042 * Factory method that performs validation.
043 * <p>
044 * A null closure or zero count returns the <code>NOPClosure</code>.
045 * A count of one returns the specified closure.
046 *
047 * @param count the number of times to execute the closure
048 * @param closure the closure to execute, not null
049 * @return the <code>for</code> closure
050 */
051 public static Closure getInstance(int count, Closure closure) {
052 if (count <= 0 || closure == null) {
053 return NOPClosure.INSTANCE;
054 }
055 if (count == 1) {
056 return closure;
057 }
058 return new ForClosure(count, closure);
059 }
060
061 /**
062 * Constructor that performs no validation.
063 * Use <code>getInstance</code> if you want that.
064 *
065 * @param count the number of times to execute the closure
066 * @param closure the closure to execute, not null
067 */
068 public ForClosure(int count, Closure closure) {
069 super();
070 iCount = count;
071 iClosure = closure;
072 }
073
074 /**
075 * Executes the closure <code>count</code> times.
076 *
077 * @param input the input object
078 */
079 public void execute(Object input) {
080 for (int i = 0; i < iCount; i++) {
081 iClosure.execute(input);
082 }
083 }
084
085 /**
086 * Gets the closure.
087 *
088 * @return the closure
089 * @since Commons Collections 3.1
090 */
091 public Closure getClosure() {
092 return iClosure;
093 }
094
095 /**
096 * Gets the count.
097 *
098 * @return the count
099 * @since Commons Collections 3.1
100 */
101 public int getCount() {
102 return iCount;
103 }
104
105 }