/*
* $Id: StrutsBeanWrapper.java 439747 2006-09-03 09:22:46Z mrdon $
*
* Copyright 2006 The Apache Software Foundation.
*
* 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 org.apache.struts2.views.freemarker;
import java.util.Map;
import java.util.Set;
import freemarker.core.CollectionAndSequence;
import freemarker.ext.beans.BeansWrapper;
import freemarker.ext.beans.MapModel;
import freemarker.ext.util.ModelFactory;
import freemarker.template.ObjectWrapper;
import freemarker.template.SimpleSequence;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
/**
* <!-- START SNIPPET: javadoc -->
*
* The StrutsBeanWrapper extends the default FreeMarker BeansWrapper and provides almost no change in functionality,
* <b>except</b> for how it handles maps. Normally, FreeMarker has two modes of operation: either support for friendly
* map built-ins (?keys, ?values, etc) but only support for String keys; OR no special built-in support (ie: ?keys
* returns the methods on the map instead of the keys) but support for String and non-String keys alike. Struts
* provides an alternative implementation that gives us the best of both worlds.
*
* <p/> It is possible that this special behavior may be confusing or can cause problems. Therefore, you can set the
* <b>struts.freemarker.wrapper.altMap</b> property in struts.properties to false, allowing the normal BeansWrapper
* logic to take place instead.
*
* <!-- END SNIPPET: javadoc -->
*/
public class StrutsBeanWrapper extends BeansWrapper {
private static final boolean altMapWrapper
= "true".equals(org.apache.struts2.config.Settings.get("struts.freemarker.wrapper.altMap"));
public TemplateModel wrap(Object object) throws TemplateModelException {
if (object instanceof TemplateBooleanModel) {
return super.wrap(object);
}
// attempt to get the best of both the SimpleMapModel and the MapModel of FM.
if (altMapWrapper && object instanceof Map) {
return getInstance(object, FriendlyMapModel.FACTORY);
}
return super.wrap(object);
}
/**
* Attempting to get the best of both worlds of FM's MapModel and SimpleMapModel, by reimplementing the isEmpty(),
* keySet() and values() methods. ?keys and ?values built-ins are thus available, just as well as plain Map
* methods.
*/
private final static class FriendlyMapModel extends MapModel implements TemplateHashModelEx {
static final ModelFactory FACTORY = new ModelFactory() {
public TemplateModel create(Object object, ObjectWrapper wrapper) {
return new FriendlyMapModel((Map) object, (BeansWrapper) wrapper);
}
};
public FriendlyMapModel(Map map, BeansWrapper wrapper) {
super(map, wrapper);
}
public boolean isEmpty() {
return ((Map) object).isEmpty();
}
protected Set keySet() {
return ((Map) object).keySet();
}
public TemplateCollectionModel values() {
return new CollectionAndSequence(new SimpleSequence(((Map) object).values(), wrapper));
}
}
}