/* Copyright 2005-2006 Tim Fennell
*
* 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.sourceforge.stripes.util.bean;
import net.sourceforge.stripes.action.ActionBean;
import net.sourceforge.stripes.validation.ValidationError;
import net.sourceforge.stripes.validation.TypeConverter;
import net.sourceforge.stripes.controller.StripesFilter;
import net.sourceforge.stripes.util.Log;
import java.util.Map;
import java.util.Locale;
import java.util.Collection;
import java.util.ArrayList;
import java.lang.reflect.Constructor;
/**
* Implementation of {@link PropertyAccessor} for interacting with Maps. Uses information
* stored in the node evaluation to determine the correct type for the Map key and converts
* the key using Stripes' type conversion system.
*
* @author Tim Fennell
* @since Stripes 1.4
*/
public class MapPropertyAccessor implements PropertyAccessor<Map<?,?>> {
private static final Log log = Log.getInstance(MapPropertyAccessor.class);
/**
* Gets the value stored in the Map under the key specified by the current node.
* @param evaluation the current node evaluation
* @param map the target Map
* @return the value stored in the map under the specified key
*/
public Object getValue(NodeEvaluation evaluation, Map<?,?> map) {
Object key = getKey(evaluation);
return map.get(key);
}
/**
* Sets the value stored in the Map under the key specified by the current node.
* @param evaluation the current node evaluation
* @param map the target Map
* @param value the value to be stored in the map under the specified key
*/
@SuppressWarnings("unchecked")
public void setValue(NodeEvaluation evaluation, Map map, Object value) {
map.put(getKey(evaluation), value);
}
/**
* Attempts to convert the key to from the expression node to the correct type
* as determined by reflection (using generics to find the Map key type). If generics
* information is not present then the type found in the expression is used (String, int etc.).
*
* @param evaluation the current node evaluation
* @return the key to use when interacting with the Map
*/
@SuppressWarnings("unchecked")
protected Object getKey(NodeEvaluation evaluation) {
Class declaredType = evaluation.getKeyType();
Class nodeType = evaluation.getNode().getTypedValue().getClass();
if (nodeType.equals(declaredType) || declaredType == null) {
return evaluation.getNode().getTypedValue();
}
else {
try {
// Collect the things needed to grab a type converter
String stringKey = evaluation.getNode().getStringValue();
ActionBean bean = (ActionBean) evaluation.getExpressionEvaluation().getBean();
Locale locale = bean.getContext().getLocale();
Collection errors = new ArrayList<ValidationError>();
TypeConverter tc = StripesFilter.getConfiguration()
.getTypeConverterFactory().getTypeConverter(declaredType, locale);
// If there is a type converter, try using it!
if (tc != null) {
Object retval = tc.convert(stringKey, declaredType, errors);
if (errors.size() == 0) return retval;
}
// Otherwise look for a String constructor
else {
Constructor c = declaredType.getConstructor(String.class);
if (c != null) {
return c.newInstance(stringKey);
}
}
}
catch (Exception e) {
log.warn("Exception while converting Map key to appropriate type. Key: ",
evaluation.getNode().getStringValue());
}
// Return the original key if we couldn't type convert it
return evaluation.getNode().getTypedValue();
}
}
}