001: /*
002: * Copyright 2001-2004 The Apache Software Foundation
003: *
004: * Licensed under the Apache License, Version 2.0 (the "License");
005: * you may not use this file except in compliance with the License.
006: * You may obtain a copy of the License at
007: *
008: * http://www.apache.org/licenses/LICENSE-2.0
009: *
010: * Unless required by applicable law or agreed to in writing, software
011: * distributed under the License is distributed on an "AS IS" BASIS,
012: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013: * See the License for the specific language governing permissions and
014: * limitations under the License.
015: */
016: package org.apache.commons.collections.functors;
017:
018: import java.io.Serializable;
019: import java.util.Collection;
020: import java.util.Iterator;
021:
022: import org.apache.commons.collections.Closure;
023:
024: /**
025: * Closure implementation that chains the specified closures together.
026: *
027: * @since Commons Collections 3.0
028: * @version $Revision: 348444 $ $Date: 2005-11-23 14:06:56 +0000 (Wed, 23 Nov 2005) $
029: *
030: * @author Stephen Colebourne
031: */
032: public class ChainedClosure implements Closure, Serializable {
033:
034: /** Serial version UID */
035: private static final long serialVersionUID = -3520677225766901240L;
036:
037: /** The closures to call in turn */
038: private final Closure[] iClosures;
039:
040: /**
041: * Factory method that performs validation and copies the parameter array.
042: *
043: * @param closures the closures to chain, copied, no nulls
044: * @return the <code>chained</code> closure
045: * @throws IllegalArgumentException if the closures array is null
046: * @throws IllegalArgumentException if any closure in the array is null
047: */
048: public static Closure getInstance(Closure[] closures) {
049: FunctorUtils.validate(closures);
050: if (closures.length == 0) {
051: return NOPClosure.INSTANCE;
052: }
053: closures = FunctorUtils.copy(closures);
054: return new ChainedClosure(closures);
055: }
056:
057: /**
058: * Create a new Closure that calls each closure in turn, passing the
059: * result into the next closure. The ordering is that of the iterator()
060: * method on the collection.
061: *
062: * @param closures a collection of closures to chain
063: * @return the <code>chained</code> closure
064: * @throws IllegalArgumentException if the closures collection is null
065: * @throws IllegalArgumentException if any closure in the collection is null
066: */
067: public static Closure getInstance(Collection closures) {
068: if (closures == null) {
069: throw new IllegalArgumentException(
070: "Closure collection must not be null");
071: }
072: if (closures.size() == 0) {
073: return NOPClosure.INSTANCE;
074: }
075: // convert to array like this to guarantee iterator() ordering
076: Closure[] cmds = new Closure[closures.size()];
077: int i = 0;
078: for (Iterator it = closures.iterator(); it.hasNext();) {
079: cmds[i++] = (Closure) it.next();
080: }
081: FunctorUtils.validate(cmds);
082: return new ChainedClosure(cmds);
083: }
084:
085: /**
086: * Factory method that performs validation.
087: *
088: * @param closure1 the first closure, not null
089: * @param closure2 the second closure, not null
090: * @return the <code>chained</code> closure
091: * @throws IllegalArgumentException if either closure is null
092: */
093: public static Closure getInstance(Closure closure1, Closure closure2) {
094: if (closure1 == null || closure2 == null) {
095: throw new IllegalArgumentException(
096: "Closures must not be null");
097: }
098: Closure[] closures = new Closure[] { closure1, closure2 };
099: return new ChainedClosure(closures);
100: }
101:
102: /**
103: * Constructor that performs no validation.
104: * Use <code>getInstance</code> if you want that.
105: *
106: * @param closures the closures to chain, not copied, no nulls
107: */
108: public ChainedClosure(Closure[] closures) {
109: super ();
110: iClosures = closures;
111: }
112:
113: /**
114: * Execute a list of closures.
115: *
116: * @param input the input object passed to each closure
117: */
118: public void execute(Object input) {
119: for (int i = 0; i < iClosures.length; i++) {
120: iClosures[i].execute(input);
121: }
122: }
123:
124: /**
125: * Gets the closures, do not modify the array.
126: * @return the closures
127: * @since Commons Collections 3.1
128: */
129: public Closure[] getClosures() {
130: return iClosures;
131: }
132:
133: }
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