src/web/org/codehaus/groovy/grails/web/taglib/GroovyGrepTag.java

   1 /* Copyright 2004-2005 the original author or authors.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at
   6  *
   7  *      http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 package org.codehaus.groovy.grails.web.taglib;
  16
  17 import org.apache.commons.lang.StringUtils;
  18 import org.codehaus.groovy.grails.web.taglib.exceptions.GrailsTagException;
  19
  20 /**
  21  *
  22  * Example:
  23  *
  24  * <code>
  25  *  <gr:grep in="${thing}" filter="${Pattern.compile('[a-zA-Z]')}">
  26  *        <p>${it}</p>
  27  *  </gr:grep>
  28  * </code>
  29  *
  30  * @author Graeme Rocher
  31  * @since 19-Jan-2006
  32  */
  33 public class GroovyGrepTag extends GroovySyntaxTag{
  34    public static final String TAG_NAME = "grep";
  35     private static final String ATTRIBUTE_FILTER = "filter";
  36
  37     public boolean isBufferWhiteSpace() {
  38         return false;
  39     }
  40
  41     public boolean hasPrecedingContent() {
  42         return true;
  43     }
  44
  45     public void doStartTag() {
  46         String in = (String) attributes.get(ATTRIBUTE_IN);
  47         String filter = (String) attributes.get(ATTRIBUTE_FILTER);
  48         if(StringUtils.isBlank(in))
  49             throw new GrailsTagException("Tag ["+TAG_NAME+"] missing required attribute ["+ATTRIBUTE_IN+"]");
  50         if(StringUtils.isBlank(filter))
  51             throw new GrailsTagException("Tag ["+TAG_NAME+"] missing required attribute ["+ATTRIBUTE_FILTER +"]");
  52
  53         out.print(in);
  54         out.print(".grep(");
  55         filter = calculateExpression(filter);
  56         out.print(filter);
  57         out.print(")");
  58         doEachMethod("");
  59     }
  60
  61     public void doEndTag() {
  62         out.println("}");
  63     }
  64
  65     public String getName() {
  66         return TAG_NAME;
  67     }
  68 }