/*******************************************************************************
 * Copyright 2010 Simon Mieth
 * 
 * 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.kabeja.processing.helper;

import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * This is a helper Map which does not support all methods of 
 * a Map.
 * @author simon
 *
 */

public class MergeMap implements Map {
    private Map base;
    private Map override;

    public MergeMap(Map base, Map override) {
        this.base = base;
        this.override = override;
    }

    public void clear() {
    }

    public boolean containsKey(Object key) {
        if (this.override.containsKey(key)) {
            return true;
        } else {
            return this.base.containsKey(key);
        }
    }

    public boolean containsValue(Object value) {
        if (this.override.containsValue(value)) {
            return true;
        } else {
            return this.base.containsValue(value);
        }
    }

    public Set entrySet() {
    	Set set = new HashSet(this.base.entrySet());
    	set.addAll(this.override.entrySet());
        return set;
        
    }

    public Object get(Object key) {
    	
    	if(this.override.containsKey(key)){
           return this.override.get(key);
    	}else{       
           return  this.base.get(key);
        }
    }

    public boolean isEmpty() {
        if (this.override.isEmpty()) {
            return true;
        } else {
            return this.base.isEmpty();
        }
    }

    public Set keySet() {
    	Set set = new HashSet(this.base.keySet());
    	set.addAll(this.override.keySet());
        return set;
    }

    public Object put(Object arg0, Object arg1) {
        return null;
    }

    public void putAll(Map arg0) {
    }

    public Object remove(Object key) {
        return null;
    }

    public int size() {
        return this.base.size();
    }

    public Collection values() {
        return null;
    }
}