/*
* $Id: AttributeMap.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.util;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import javax.servlet.jsp.PageContext;
import org.apache.struts2.ServletActionContext;
/**
* A Map that holds 4 levels of scope.
* <p/>
* The scopes are the ones known in the web world.:
* <ul>
* <li>Page scope</li>
* <li>Request scope</li>
* <li>Session scope</li>
* <li>Application scope</li>
* </ul>
* A object is searched in the order above, starting from page and ending at application scope.
*
*/
public class AttributeMap implements Map {
protected static final String UNSUPPORTED = "method makes no sense for a simplified map";
Map context;
public AttributeMap(Map context) {
this.context = context;
}
public boolean isEmpty() {
throw new UnsupportedOperationException(UNSUPPORTED);
}
public void clear() {
throw new UnsupportedOperationException(UNSUPPORTED);
}
public boolean containsKey(Object key) {
return (get(key) != null);
}
public boolean containsValue(Object value) {
throw new UnsupportedOperationException(UNSUPPORTED);
}
public Set entrySet() {
return Collections.EMPTY_SET;
}
public Object get(Object key) {
PageContext pc = getPageContext();
if (pc == null) {
Map request = (Map) context.get("request");
Map session = (Map) context.get("session");
Map application = (Map) context.get("application");
if ((request != null) && (request.get(key) != null)) {
return request.get(key);
} else if ((session != null) && (session.get(key) != null)) {
return session.get(key);
} else if ((application != null) && (application.get(key) != null)) {
return application.get(key);
}
} else {
try{
return pc.findAttribute(key.toString());
}catch (NullPointerException npe){
return null;
}
}
return null;
}
public Set keySet() {
return Collections.EMPTY_SET;
}
public Object put(Object key, Object value) {
PageContext pc = getPageContext();
if (pc != null) {
pc.setAttribute(key.toString(), value);
}
return null;
}
public void putAll(Map t) {
throw new UnsupportedOperationException(UNSUPPORTED);
}
public Object remove(Object key) {
throw new UnsupportedOperationException(UNSUPPORTED);
}
public int size() {
throw new UnsupportedOperationException(UNSUPPORTED);
}
public Collection values() {
return Collections.EMPTY_SET;
}
private PageContext getPageContext() {
return (PageContext) context.get(ServletActionContext.PAGE_CONTEXT);
}
}