/**
 * Copyright 2010 JBoss Inc
 *
 * 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.drools.runtime.pipeline.impl;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

import org.drools.runtime.pipeline.Expression;
import org.drools.runtime.pipeline.PipelineContext;
import org.drools.runtime.pipeline.Receiver;
import org.mvel2.MVEL;
import org.mvel2.ParserContext;
import org.mvel2.compiler.ExpressionCompiler;

public class MvelExpression extends BaseEmitter
    implements
    Expression,
    Receiver {
    private Serializable expr;

    public MvelExpression(String text) {
        final ParserContext parserContext = new ParserContext();
        parserContext.setStrictTypeEnforcement( false );

        ExpressionCompiler compiler = new ExpressionCompiler( text );
        this.expr = compiler.compile( parserContext );
    }

    public void receive(Object object,
                       PipelineContext context) {
        Object result = null;
        try {
            Map<String, Object> vars = new HashMap<String, Object>(1);
            vars.put( "context", context );
            result = MVEL.executeExpression( this.expr,
                                    object,
                                    vars );
        } catch ( Exception e ) {
            handleException( this,
                             object,
                             e );
        }
        emit( result,
              context );
    }

}