001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.betwixt.io.read;
019
020 import java.util.ArrayList;
021 import java.util.List;
022
023 import org.apache.commons.betwixt.ElementDescriptor;
024 import org.apache.commons.betwixt.expression.Context;
025 import org.apache.commons.betwixt.expression.Updater;
026 import org.xml.sax.Attributes;
027
028 /**
029 * <p>Acts to bind an array property.
030 * Note that this is intended to be used to map
031 * properties with a setter taking an array
032 * but which do not have an adder.</p>
033 * <p>
034 * <strong>Note</strong> this implementation has state
035 * and therefore cannot be used concurrently (in simultaneous readings).
036 * </p>
037 * @author <a href='http://commons.apache.org/'>Apache Commons Team</a>
038 * @version $Revision: 561314 $
039 */
040 public class ArrayBindAction extends MappingAction.Base {
041
042
043 /**
044 * Factory method creates implementations to map arrays.
045 * @param elementDescriptor <code>ElementDescriptor</code> to be mapped,
046 * not null
047 * @return <code>MappingAction</code>, not null
048 */
049 public static final MappingAction createMappingAction(ElementDescriptor elementDescriptor) {
050 MappingAction result = new ArrayBindAction();
051 if (elementDescriptor.getSingularPropertyType() != null &&
052 !elementDescriptor.getSingularPropertyType().isArray()) {
053 result = BeanBindAction.INSTANCE;
054 }
055 return result;
056 }
057
058 private BeanMapping beanMapping = new BeanMapping();
059 private Updater originalUpdater;
060
061 /**
062 * Mapping arrays requires the addition of a temporary object
063 * (an <code>ArrayList</code>) into the stack together with an
064 * updater for that object.
065 *
066 */
067 public MappingAction begin(
068 String namespace,
069 String name,
070 Attributes attributes,
071 ReadContext context)
072 throws Exception {
073 // push an array onto the object stack
074 context.pushBean(new ArrayList());
075 return this;
076 }
077
078 /**
079 * Pops the <code>ArrayList</code> and the updater from
080 * their stacks. The original updater is called with the
081 * result of the convertion.
082 */
083 public void end(ReadContext context) throws Exception {
084 if (originalUpdater != null) {
085 // create an array of appropriate type
086 List values = (List) context.popBean();
087 originalUpdater.update(context, values);
088 }
089 }
090
091 /** Construct a delegating implmentation that wraps the real bean creator */
092 public MappingAction next(
093 String namespace,
094 String name,
095 Attributes attributes,
096 ReadContext context)
097 throws Exception {
098 originalUpdater = context.getCurrentUpdater();
099 MappingAction nextBindAction = BeanBindAction.INSTANCE;
100 beanMapping.setDelegate(nextBindAction);
101 return beanMapping;
102 }
103
104
105
106 /** Updates a list by adding the new value */
107 private static class ListUpdater implements Updater {
108 /** Singleton */
109 private static final ListUpdater INSTANCE = new ListUpdater();
110
111 /** Update by adding the new value to the list */
112 public void update(Context context, Object newValue) {
113 List values = (List) context.getBean();
114 values.add(newValue);
115 }
116
117 }
118
119 private static class BeanMapping extends MappingAction.Base {
120 private MappingAction delegate;
121
122 BeanMapping() {}
123
124
125 /**
126 * Gets the action to which the bean binding is delegated.
127 * @return <code>MappingAction</code> delegate, not null
128 */
129 MappingAction getDelegate() {
130 return delegate;
131 }
132
133 /**
134 * Sets the action to which the bean binding is delegated.
135 * @param action< code>MappingAction</code> delegate, not null
136 */
137 void setDelegate(MappingAction action) {
138 delegate = action;
139 }
140
141 /** Push updater and then delegate */
142 public MappingAction begin(
143 String namespace,
144 String name,
145 Attributes attributes,
146 ReadContext context)
147 throws Exception {
148 context.pushUpdater(ListUpdater.INSTANCE);
149 delegate = delegate.begin(namespace, name, attributes, context);
150 return this;
151 }
152
153 /** Delegate to delegate (Doh!) */
154 public void body(String text, ReadContext context) throws Exception {
155 delegate.body(text, context);
156 }
157
158 /** Call delegate then pop <code>Updater</code> */
159 public void end(ReadContext context) throws Exception {
160 delegate.end(context);
161 Updater updater = context.popUpdater();
162 }
163
164 /** Use delegate to create next action */
165 public MappingAction next(
166 String namespace,
167 String name,
168 Attributes attributes,
169 ReadContext context)
170 throws Exception {
171 return delegate.next(namespace, name, attributes, context);
172 }
173
174
175 }
176 }