/**********************************************************************
Copyright (c) 2009 Asfun Net.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
**********************************************************************/
package net.asfun.jangod.lib.tag;
import net.asfun.jangod.base.Constants;
import net.asfun.jangod.interpret.InterpretException;
import net.asfun.jangod.interpret.JangodInterpreter;
import net.asfun.jangod.lib.Tag;
import net.asfun.jangod.tree.Node;
import net.asfun.jangod.tree.NodeList;
/**
* {% ifchange var %}
* @author anysome
*
*/
public class IfchangedTag implements Tag{
final String LASTKEY = "'IF\"CHG";
final String TAGNAME = "ifchanged";
final String ENDTAGNAME = "endif";
@Override
public String interpreter(NodeList carries, String helpers, JangodInterpreter interpreter)
throws InterpretException {
if ( helpers.length() == 0 ) {
throw new InterpretException("Tag 'ifchanged' expects 1 helper >>> 0");
}
boolean isChanged = true;
String var = helpers;
Object older = interpreter.fetchRuntimeScope(LASTKEY + var);
Object test = interpreter.retraceVariable(var);
if ( older == null ) {
if ( test == null ) {
isChanged = false;
}
} else if ( older.equals(test) ) {
isChanged = false;
}
interpreter.assignRuntimeScope(LASTKEY + var, test);
if ( isChanged ) {
StringBuffer sb = new StringBuffer();
for(Node node : carries) {
sb.append(node.render(interpreter));
}
return sb.toString();
}
return Constants.STR_BLANK;
}
@Override
public String getEndTagName() {
return ENDTAGNAME;
}
@Override
public String getName() {
return TAGNAME;
}
}