001: /*
002: * $Id: StrutsBeanWrapper.java 474191 2006-11-13 08:30:40Z mrdon $
003: *
004: * Licensed to the Apache Software Foundation (ASF) under one
005: * or more contributor license agreements. See the NOTICE file
006: * distributed with this work for additional information
007: * regarding copyright ownership. The ASF licenses this file
008: * to you under the Apache License, Version 2.0 (the
009: * "License"); you may not use this file except in compliance
010: * with the License. You may obtain a copy of the License at
011: *
012: * http://www.apache.org/licenses/LICENSE-2.0
013: *
014: * Unless required by applicable law or agreed to in writing,
015: * software distributed under the License is distributed on an
016: * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017: * KIND, either express or implied. See the License for the
018: * specific language governing permissions and limitations
019: * under the License.
020: */
021: package org.apache.struts2.views.freemarker;
022:
023: import java.util.Map;
024: import java.util.Set;
025:
026: import org.apache.struts2.StrutsConstants;
027:
028: import freemarker.core.CollectionAndSequence;
029: import freemarker.ext.beans.BeansWrapper;
030: import freemarker.ext.beans.MapModel;
031: import freemarker.ext.util.ModelFactory;
032: import freemarker.template.ObjectWrapper;
033: import freemarker.template.SimpleSequence;
034: import freemarker.template.TemplateBooleanModel;
035: import freemarker.template.TemplateCollectionModel;
036: import freemarker.template.TemplateHashModelEx;
037: import freemarker.template.TemplateModel;
038: import freemarker.template.TemplateModelException;
039:
040: /**
041: * <!-- START SNIPPET: javadoc -->
042: *
043: * The StrutsBeanWrapper extends the default FreeMarker BeansWrapper and provides almost no change in functionality,
044: * <b>except</b> for how it handles maps. Normally, FreeMarker has two modes of operation: either support for friendly
045: * map built-ins (?keys, ?values, etc) but only support for String keys; OR no special built-in support (ie: ?keys
046: * returns the methods on the map instead of the keys) but support for String and non-String keys alike. Struts
047: * provides an alternative implementation that gives us the best of both worlds.
048: *
049: * <p/> It is possible that this special behavior may be confusing or can cause problems. Therefore, you can set the
050: * <b>struts.freemarker.wrapper.altMap</b> property in struts.properties to false, allowing the normal BeansWrapper
051: * logic to take place instead.
052: *
053: * <!-- END SNIPPET: javadoc -->
054: */
055: public class StrutsBeanWrapper extends BeansWrapper {
056: private boolean altMapWrapper;
057:
058: StrutsBeanWrapper(boolean altMapWrapper) {
059: this .altMapWrapper = altMapWrapper;
060: }
061:
062: public TemplateModel wrap(Object object)
063: throws TemplateModelException {
064: if (object instanceof TemplateBooleanModel) {
065: return super .wrap(object);
066: }
067:
068: // attempt to get the best of both the SimpleMapModel and the MapModel of FM.
069: if (altMapWrapper && object instanceof Map) {
070: return getInstance(object, FriendlyMapModel.FACTORY);
071: }
072:
073: return super .wrap(object);
074: }
075:
076: /**
077: * Attempting to get the best of both worlds of FM's MapModel and SimpleMapModel, by reimplementing the isEmpty(),
078: * keySet() and values() methods. ?keys and ?values built-ins are thus available, just as well as plain Map
079: * methods.
080: */
081: private final static class FriendlyMapModel extends MapModel
082: implements TemplateHashModelEx {
083: static final ModelFactory FACTORY = new ModelFactory() {
084: public TemplateModel create(Object object,
085: ObjectWrapper wrapper) {
086: return new FriendlyMapModel((Map) object,
087: (BeansWrapper) wrapper);
088: }
089: };
090:
091: public FriendlyMapModel(Map map, BeansWrapper wrapper) {
092: super (map, wrapper);
093: }
094:
095: public boolean isEmpty() {
096: return ((Map) object).isEmpty();
097: }
098:
099: protected Set keySet() {
100: return ((Map) object).keySet();
101: }
102:
103: public TemplateCollectionModel values() {
104: return new CollectionAndSequence(new SimpleSequence(
105: ((Map) object).values(), wrapper));
106: }
107: }
108: }
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