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org.apache.commons.jelly.tags.core.ForEachTag |
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1 | /* |
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2 | * Copyright 2002,2004 The Apache Software Foundation. |
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3 | * |
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4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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5 | * you may not use this file except in compliance with the License. |
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6 | * You may obtain a copy of the License at |
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7 | * |
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8 | * http://www.apache.org/licenses/LICENSE-2.0 |
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9 | * |
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10 | * Unless required by applicable law or agreed to in writing, software |
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11 | * distributed under the License is distributed on an "AS IS" BASIS, |
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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13 | * See the License for the specific language governing permissions and |
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14 | * limitations under the License. |
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15 | */ |
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16 | ||
17 | package org.apache.commons.jelly.tags.core; |
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18 | ||
19 | import java.util.Iterator; |
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20 | ||
21 | import javax.servlet.jsp.jstl.core.LoopTagStatus; |
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22 | ||
23 | import org.apache.commons.jelly.JellyTagException; |
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24 | import org.apache.commons.jelly.MissingAttributeException; |
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25 | import org.apache.commons.jelly.TagSupport; |
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26 | import org.apache.commons.jelly.XMLOutput; |
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27 | import org.apache.commons.jelly.expression.Expression; |
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28 | import org.apache.commons.jelly.impl.BreakException; |
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29 | import org.apache.commons.logging.Log; |
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30 | import org.apache.commons.logging.LogFactory; |
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31 | ||
32 | /** |
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33 | * Iterates over a collection, iterator or an array of objects. |
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34 | * Uses the same syntax as the <a href="http://java.sun.com/products/jsp/jstl/">JSTL</a> |
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35 | * <code>forEach</code> tag does. |
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36 | * |
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37 | * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> |
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38 | * @version $Revision: 155420 $ |
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39 | */ |
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40 | public class ForEachTag extends TagSupport { |
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41 | ||
42 | /** The Log to which logging calls will be made. */ |
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43 | 546 | private static final Log log = LogFactory.getLog(ForEachTag.class); |
44 | ||
45 | /** Holds the variable name to export for the item being iterated over. */ |
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46 | private Expression items; |
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47 | ||
48 | /** |
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49 | * If specified then the current item iterated through will be defined |
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50 | * as the given variable name. |
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51 | */ |
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52 | private String var; |
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53 | ||
54 | /** |
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55 | * If specified then the current index counter will be defined |
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56 | * as the given variable name. |
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57 | */ |
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58 | private String indexVar; |
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59 | ||
60 | /** variable to hold loop status */ |
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61 | private String statusVar; |
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62 | ||
63 | /** The starting index value */ |
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64 | private int begin; |
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65 | ||
66 | /** The ending index value */ |
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67 | 351 | private int end = Integer.MAX_VALUE; |
68 | ||
69 | /** The index increment step */ |
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70 | 351 | private int step = 1; |
71 | ||
72 | /** The iteration index */ |
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73 | private int index; |
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74 | ||
75 | 351 | public ForEachTag() { |
76 | 351 | } |
77 | ||
78 | // Tag interface |
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79 | ||
80 | //------------------------------------------------------------------------- |
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81 | public void doTag(XMLOutput output) throws MissingAttributeException, JellyTagException { |
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82 | ||
83 | 351 | if (log.isDebugEnabled()) { |
84 | 0 | log.debug("running with items: " + items); |
85 | } |
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86 | ||
87 | try { |
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88 | 351 | if (items != null) { |
89 | 52 | Iterator iter = items.evaluateAsIterator(context); |
90 | ||
91 | 52 | if (log.isDebugEnabled()) { |
92 | 0 | log.debug("Iterating through: " + iter); |
93 | } |
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94 | ||
95 | // ignore the first items of the iterator |
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96 | 78 | for (index = 0; index < begin && iter.hasNext(); index++ ) { |
97 | 26 | iter.next(); |
98 | } |
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99 | ||
100 | // set up the status |
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101 | 52 | LoopStatus status = null; |
102 | 52 | if (statusVar != null) |
103 | { |
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104 | // set up statii as required by JSTL |
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105 | 13 | Integer statusBegin = (begin == 0) ? null : new Integer(begin); |
106 | 13 | Integer statusEnd = (end == Integer.MAX_VALUE) ? null : new Integer(end); |
107 | 13 | Integer statusStep = (step == 1) ? null : new Integer(step); |
108 | 13 | status = new LoopStatus(statusBegin, statusEnd, statusStep); |
109 | 13 | context.setVariable(statusVar, status); |
110 | } |
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111 | ||
112 | 52 | boolean firstTime = true; |
113 | 52 | int count = 0; |
114 | 195 | while (iter.hasNext() && index <= end) { |
115 | 143 | Object value = iter.next(); |
116 | 143 | if (var != null) { |
117 | 143 | context.setVariable(var, value); |
118 | } |
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119 | 143 | if (indexVar != null) { |
120 | 0 | context.setVariable(indexVar, new Integer(index)); |
121 | } |
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122 | // set the status var up |
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123 | 143 | if (statusVar != null) { |
124 | 39 | count++; |
125 | 39 | status.setCount(count); |
126 | 39 | status.setCurrent(value); |
127 | 39 | status.setFirst(firstTime); |
128 | 39 | status.setIndex(index); |
129 | // set first time up for the next iteration. |
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130 | 39 | if (firstTime) { |
131 | 13 | firstTime = !firstTime; |
132 | } |
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133 | } |
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134 | // now we need to work out the next index for status isLast |
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135 | // and also advance the iterator and index for the loop. |
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136 | 143 | boolean finished = false; |
137 | 143 | index++; |
138 | 182 | for ( int i = 1; i < step && !finished; i++, index++ ) { |
139 | 39 | if ( ! iter.hasNext() ) { |
140 | 0 | finished = true; |
141 | 0 | } |
142 | else { |
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143 | 39 | iter.next(); |
144 | } |
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145 | } |
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146 | ||
147 | 143 | if (statusVar != null) { |
148 | 39 | status.setLast(finished || !iter.hasNext() || index > end); |
149 | } |
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150 | 143 | invokeBody(output); |
151 | ||
152 | 143 | } |
153 | 52 | } |
154 | else { |
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155 | 299 | if ( end == Integer.MAX_VALUE && begin == 0 ) { |
156 | 0 | throw new MissingAttributeException( "items" ); |
157 | } |
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158 | else { |
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159 | 299 | String varName = var; |
160 | 299 | if ( varName == null ) { |
161 | 0 | varName = indexVar; |
162 | } |
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163 | // set up the status |
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164 | 299 | LoopStatus status = null; |
165 | 299 | if (statusVar != null) |
166 | { |
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167 | // set up statii as required by JSTL |
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168 | 13 | Integer statusBegin = new Integer(begin); |
169 | 13 | Integer statusEnd = new Integer(end); |
170 | 13 | Integer statusStep = new Integer(step); |
171 | 13 | status = new LoopStatus(statusBegin, statusEnd, statusStep); |
172 | 13 | context.setVariable(statusVar, status); |
173 | } |
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174 | ||
175 | 299 | int count = 0; |
176 | 1716 | for (index = begin; index <= end; index += step ) { |
177 | ||
178 | 1599 | Object value = new Integer(index); |
179 | 1599 | if (varName != null) { |
180 | 1599 | context.setVariable(varName, value); |
181 | } |
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182 | // set the status var up |
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183 | 1599 | if (status != null) { |
184 | 39 | count++; |
185 | 39 | status.setIndex(index); |
186 | 39 | status.setCount(count); |
187 | 39 | status.setCurrent(value); |
188 | 39 | status.setFirst(index == begin); |
189 | 39 | status.setLast(index > end - step); |
190 | } |
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191 | 1599 | invokeBody(output); |
192 | } |
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193 | } |
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194 | } |
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195 | } |
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196 | 182 | catch (BreakException e) { |
197 | 182 | if (log.isDebugEnabled()) { |
198 | 0 | log.debug("loop terminated by break: " + e, e); |
199 | } |
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200 | 169 | } |
201 | 351 | } |
202 | ||
203 | // Properties |
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204 | //------------------------------------------------------------------------- |
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205 | ||
206 | /** |
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207 | * Sets the expression used to iterate over. |
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208 | * This expression could resolve to an Iterator, Collection, Map, Array, |
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209 | * Enumeration or comma separated String. |
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210 | */ |
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211 | public void setItems(Expression items) { |
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212 | 52 | this.items = items; |
213 | 52 | } |
214 | ||
215 | /** Sets the variable name to export for the item being iterated over |
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216 | */ |
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217 | public void setVar(String var) { |
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218 | 351 | this.var = class="keyword">var; |
219 | 351 | } |
220 | ||
221 | /** Sets the variable name to export the current index counter to |
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222 | */ |
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223 | public void setIndexVar(String indexVar) { |
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224 | 0 | this.indexVar = indexVar; |
225 | 0 | } |
226 | ||
227 | /** Sets the starting index value |
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228 | */ |
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229 | public void setBegin(int begin) { |
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230 | 312 | this.begin = begin; |
231 | 312 | } |
232 | ||
233 | /** Sets the ending index value |
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234 | */ |
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235 | public void setEnd(int end) { |
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236 | 312 | this.end = end; |
237 | 312 | } |
238 | ||
239 | /** Sets the index increment step |
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240 | */ |
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241 | public void setStep(int step) { |
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242 | 26 | this.step = step; |
243 | 26 | } |
244 | ||
245 | /** |
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246 | * Sets the variable name to export the current status to. |
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247 | * The status is an implementation of the JSTL LoopTagStatus interface that provides |
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248 | * the following bean properties: |
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249 | * <ul> |
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250 | * <li>current - the current value of the loop items being iterated</li> |
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251 | * <li>index - the current index of the items being iterated</li> |
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252 | * <li>first - true if this is the first iteration, false otherwise</li> |
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253 | * <li>last - true if this is the last iteration, false otherwise</li> |
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254 | * <li>begin - the starting index of the loop</li> |
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255 | * <li>step - the stepping value of the loop</li> |
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256 | * <li>end - the end index of the loop</li> |
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257 | * </ul> |
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258 | */ |
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259 | public void setVarStatus(String var) { |
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260 | 26 | this.statusVar = var; |
261 | 26 | } |
262 | ||
263 | /** |
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264 | * Holds the status of the loop. |
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265 | */ |
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266 | public static final class LoopStatus implements LoopTagStatus |
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267 | { |
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268 | private Integer begin; |
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269 | private int count; |
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270 | private Object current; |
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271 | private Integer end; |
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272 | private int index; |
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273 | private Integer step; |
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274 | private boolean first; |
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275 | private boolean last; |
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276 | ||
277 | public LoopStatus(Integer begin, Integer end, Integer step) { |
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278 | this.begin = begin; |
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279 | this.end = end; |
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280 | this.step = step; |
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281 | } |
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282 | /** |
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283 | * @return Returns the begin. |
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284 | */ |
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285 | public Integer getBegin() { |
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286 | return begin; |
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287 | } |
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288 | /** |
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289 | * @return Returns the count. |
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290 | */ |
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291 | public int getCount() { |
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292 | return count; |
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293 | } |
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294 | /** |
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295 | * @return Returns the current. |
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296 | */ |
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297 | public Object getCurrent() { |
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298 | return current; |
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299 | } |
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300 | /** |
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301 | * @return Returns the end. |
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302 | */ |
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303 | public Integer getEnd() { |
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304 | return end; |
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305 | } |
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306 | /** |
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307 | * @return Returns the first. |
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308 | */ |
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309 | public boolean isFirst() { |
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310 | return first; |
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311 | } |
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312 | /** |
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313 | * @return Returns the index. |
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314 | */ |
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315 | public int getIndex() { |
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316 | return index; |
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317 | } |
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318 | /** |
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319 | * @return Returns the last. |
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320 | */ |
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321 | public boolean isLast() { |
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322 | return last; |
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323 | } |
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324 | /** |
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325 | * @return Returns the step. |
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326 | */ |
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327 | public Integer getStep() { |
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328 | return step; |
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329 | } |
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330 | /** |
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331 | * @param count The count to set. |
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332 | */ |
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333 | public void setCount(int count) { |
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334 | this.count = count; |
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335 | } |
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336 | /** |
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337 | * @param current The current to set. |
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338 | */ |
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339 | public void setCurrent(Object current) { |
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340 | this.current = current; |
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341 | } |
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342 | /** |
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343 | * @param first The first to set. |
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344 | */ |
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345 | public void setFirst(boolean first) { |
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346 | this.first = first; |
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347 | } |
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348 | /** |
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349 | * @param last The last to set. |
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350 | */ |
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351 | public void setLast(boolean last) { |
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352 | this.last = last; |
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353 | } |
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354 | /** |
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355 | * @param index The index to set. |
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356 | */ |
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357 | public void setIndex(int index) { |
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358 | this.index = index; |
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359 | } |
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360 | } |
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361 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |