View Javadoc
1 /* 2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/core/ForEachTag.java,v 1.15 2002/06/26 14:50:43 jstrachan Exp $ 3 * $Revision: 1.15 $ 4 * $Date: 2002/06/26 14:50:43 $ 5 * 6 * ==================================================================== 7 * 8 * The Apache Software License, Version 1.1 9 * 10 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights 11 * reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in 22 * the documentation and/or other materials provided with the 23 * distribution. 24 * 25 * 3. The end-user documentation included with the redistribution, if 26 * any, must include the following acknowlegement: 27 * "This product includes software developed by the 28 * Apache Software Foundation (http://www.apache.org/)." 29 * Alternately, this acknowlegement may appear in the software itself, 30 * if and wherever such third-party acknowlegements normally appear. 31 * 32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software 33 * Foundation" must not be used to endorse or promote products derived 34 * from this software without prior written permission. For written 35 * permission, please contact apache@apache.org. 36 * 37 * 5. Products derived from this software may not be called "Apache" 38 * nor may "Apache" appear in their names without prior written 39 * permission of the Apache Group. 40 * 41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 52 * SUCH DAMAGE. 53 * ==================================================================== 54 * 55 * This software consists of voluntary contributions made by many 56 * individuals on behalf of the Apache Software Foundation. For more 57 * information on the Apache Software Foundation, please see 58 * <http://www.apache.org/>;. 59 * 60 * $Id: ForEachTag.java,v 1.15 2002/06/26 14:50:43 jstrachan Exp $ 61 */ 62 63 package org.apache.commons.jelly.tags.core; 64 65 import java.io.IOException; 66 import java.io.Writer; 67 import java.util.Iterator; 68 import java.util.List; 69 70 import org.apache.commons.jelly.JellyContext; 71 import org.apache.commons.jelly.MissingAttributeException; 72 import org.apache.commons.jelly.Script; 73 import org.apache.commons.jelly.TagSupport; 74 import org.apache.commons.jelly.XMLOutput; 75 import org.apache.commons.jelly.expression.Expression; 76 77 import org.apache.commons.logging.Log; 78 import org.apache.commons.logging.LogFactory; 79 80 /*** A tag which performs an iteration over the results of an XPath expression 81 * 82 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> 83 * @version $Revision: 1.15 $ 84 */ 85 public class ForEachTag extends TagSupport { 86 87 /*** The Log to which logging calls will be made. */ 88 private static final Log log = LogFactory.getLog(ForEachTag.class); 89 90 /*** Holds the variable name to export for the item being iterated over. */ 91 private Expression items; 92 93 /*** 94 * If specified then the current item iterated through will be defined 95 * as the given variable name. 96 */ 97 private String var; 98 99 /*** 100 * If specified then the current index counter will be defined 101 * as the given variable name. 102 */ 103 private String indexVar; 104 105 /*** The starting index value */ 106 private int begin; 107 108 /*** The ending index value */ 109 private int end = Integer.MAX_VALUE; 110 111 /*** The index increment step */ 112 private int step = 1; 113 114 /*** The iteration index */ 115 private int index; 116 117 public ForEachTag() { 118 } 119 120 // Tag interface 121 122 //------------------------------------------------------------------------- 123 public void doTag(XMLOutput output) throws Exception { 124 125 if (log.isDebugEnabled()) { 126 log.debug("running with items: " + items); 127 } 128 129 if (items != null) { 130 Iterator iter = items.evaluateAsIterator(context); 131 if (log.isDebugEnabled()) { 132 log.debug("Iterating through: " + iter); 133 } 134 135 // ignore the first items of the iterator 136 for (index = 0; index < begin && iter.hasNext(); index++ ) { 137 iter.next(); 138 } 139 140 while (iter.hasNext() && index < end) { 141 Object value = iter.next(); 142 if (var != null) { 143 context.setVariable(var, value); 144 } 145 if (indexVar != null) { 146 context.setVariable(indexVar, new Integer(index)); 147 } 148 invokeBody(output); 149 150 // now we need to move to next index 151 index++; 152 for ( int i = 1; i < step; i++, index++ ) { 153 if ( ! iter.hasNext() ) { 154 return; 155 } 156 iter.next(); 157 } 158 } 159 } 160 else { 161 if ( end == Integer.MAX_VALUE && begin == 0 ) { 162 throw new MissingAttributeException( "items" ); 163 } 164 else { 165 String varName = var; 166 if ( varName == null ) { 167 varName = indexVar; 168 } 169 170 for (index = begin; index < end; index += step ) { 171 172 if (varName != null) { 173 Object value = new Integer(index); 174 context.setVariable(varName, value); 175 } 176 invokeBody(output); 177 } 178 } 179 } 180 } 181 182 // Properties 183 //------------------------------------------------------------------------- 184 185 /*** Sets the expression used to iterate over 186 */ 187 public void setItems(Expression items) { 188 this.items = items; 189 } 190 191 /*** Sets the variable name to export for the item being iterated over 192 */ 193 public void setVar(String var) { 194 this.var = var; 195 } 196 197 /*** Sets the variable name to export the current index counter to 198 */ 199 public void setIndexVar(String indexVar) { 200 this.indexVar = indexVar; 201 } 202 203 /*** Sets the starting index value 204 */ 205 public void setBegin(int begin) { 206 this.begin = begin; 207 } 208 209 /*** Sets the ending index value 210 */ 211 public void setEnd(int end) { 212 this.end = end; 213 } 214 215 /*** Sets the index increment step 216 */ 217 public void setStep(int step) { 218 this.step = step; 219 } 220 }

This page was automatically generated by Maven