//  GPars (formerly GParallelizer)
//
//  Copyright © 2008-9  The original author or authors
//
//  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 groovyx.gpars.dataflow;

import org.codehaus.groovy.runtime.InvokerHelper;

/**
 * Data flow expression which invokes method of object after receiver and all arguments became available
 *
 * @author Alex Tkachman
 */
public class DataFlowInvocationExpression extends DataFlowComplexExpression<Object> {
    private static final long serialVersionUID = -678669663648650627L;
    private Object receiver;
    private final String methodName;

    public DataFlowInvocationExpression(final Object receiver, final String methodName, final Object[] args) {
        super(args);
        this.receiver = receiver;
        this.methodName = methodName;
        subscribe();
    }

    @Override
    protected Object evaluate() {
        if (receiver instanceof DataFlowExpression) {
            receiver = ((DataFlowExpression<Object>) receiver).value;
        }

        super.evaluate();

        return InvokerHelper.invokeMethod(receiver, methodName, args);
    }

    @Override
    protected void subscribe(final DataFlowExpressionsCollector listener) {
        if (receiver instanceof DataFlowExpression) {
            receiver = listener.subscribe(receiver);
        }

        super.subscribe(listener);
    }
}