Tomcat example source code file (MapELResolver.java)

This example Tomcat source code file (MapELResolver.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

bean, class, elexception, featuredescriptor, iterator, javabean, map, map, mapelresolver, nullpointerexception, nullpointerexception, object, object, propertynotfoundexception, propertynotfoundexception, propertynotwritableexception, util

The Tomcat MapELResolver.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 javax.el;

import java.beans.FeatureDescriptor;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class MapELResolver extends ELResolver {

	private final static Class UNMODIFIABLE = Collections.unmodifiableMap(
			new HashMap()).getClass();

	private final boolean readOnly;

	public MapELResolver() {
		this.readOnly = false;
	}

	public MapELResolver(boolean readOnly) {
		this.readOnly = readOnly;
	}

	public Object getValue(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		if (context == null) {
			throw new NullPointerException();
		}

		if (base instanceof Map) {
			context.setPropertyResolved(true);
			return ((Map) base).get(property);
		}
		
		return null;
	}

	public Class<?> getType(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		if (context == null) {
			throw new NullPointerException();
		}

		if (base instanceof Map) {
			context.setPropertyResolved(true);
			Object obj = ((Map) base).get(property);
			return (obj != null) ? obj.getClass() : null;
		}
		
		return null;
	}

	public void setValue(ELContext context, Object base, Object property,
			Object value) throws NullPointerException,
			PropertyNotFoundException, PropertyNotWritableException,
			ELException {
		if (context == null) {
			throw new NullPointerException();
		}

		if (base instanceof Map) {
			context.setPropertyResolved(true);

			if (this.readOnly) {
				throw new PropertyNotWritableException(message(context,
						"resolverNotWriteable", new Object[] { base.getClass()
								.getName() }));
			}

			try {
				((Map) base).put(property, value);
			} catch (UnsupportedOperationException e) {
				throw new PropertyNotWritableException(e);
			}
		}
	}

	public boolean isReadOnly(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		if (context == null) {
			throw new NullPointerException();
		}

		if (base instanceof Map) {
			context.setPropertyResolved(true);
			return this.readOnly || UNMODIFIABLE.equals(base.getClass());
		}
		
		return this.readOnly;
	}

	public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
		if (base instanceof Map) {
			Iterator itr = ((Map) base).keySet().iterator();
			List<FeatureDescriptor> feats = new ArrayList();
			Object key;
			FeatureDescriptor desc;
			while (itr.hasNext()) {
				key = itr.next();
				desc = new FeatureDescriptor();
				desc.setDisplayName(key.toString());
				desc.setExpert(false);
				desc.setHidden(false);
				desc.setName(key.toString());
				desc.setPreferred(true);
				desc.setValue(RESOLVABLE_AT_DESIGN_TIME, Boolean.FALSE);
				desc.setValue(TYPE, key.getClass());
				feats.add(desc);
			}
			return feats.iterator();
		}
		return null;
	}

	public Class<?> getCommonPropertyType(ELContext context, Object base) {
		if (base instanceof Map) {
			return Object.class;
		}
		return null;
	}

}