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/*
 * 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 getFeatureDescriptors(ELContext context, Object base) {
        if (base instanceof Map) {
            Iterator itr = ((Map) base).keySet().iterator();
            List 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;
    }

}