/*
 * 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 org.apache.flink.optimizer.plan;

import static org.apache.flink.optimizer.plan.PlanNode.SourceAndDamReport.FOUND_SOURCE;
import static org.apache.flink.optimizer.plan.PlanNode.SourceAndDamReport.NOT_FOUND;

import java.util.Collections;

import org.apache.flink.api.common.typeutils.TypeSerializerFactory;
import org.apache.flink.optimizer.dag.DataSourceNode;
import org.apache.flink.optimizer.dataproperties.GlobalProperties;
import org.apache.flink.optimizer.dataproperties.LocalProperties;
import org.apache.flink.runtime.operators.DriverStrategy;
import org.apache.flink.util.Visitor;

/**
 * Plan candidate node for data flow sources that have no input and no special strategies.
 */
public class SourcePlanNode extends PlanNode {
	
	private TypeSerializerFactory<?> serializer;
	
	/**
	 * Constructs a new source candidate node that uses <i>NONE</i> as its local strategy.
	 * 
	 * @param template The template optimizer node that this candidate is created for.
	 */
	public SourcePlanNode(DataSourceNode template, String nodeName) {
		this(template, nodeName, new GlobalProperties(), new LocalProperties());
	}

	public SourcePlanNode(DataSourceNode template, String nodeName, GlobalProperties gprops, LocalProperties lprops) {
		super(template, nodeName, DriverStrategy.NONE);

		this.globalProps = gprops;
		this.localProps = lprops;
		updatePropertiesWithUniqueSets(template.getUniqueFields());
	}

	// --------------------------------------------------------------------------------------------
	
	public DataSourceNode getDataSourceNode() {
		return (DataSourceNode) this.template;
	}
	
	/**
	 * Gets the serializer from this PlanNode.
	 *
	 * @return The serializer.
	 */
	public TypeSerializerFactory<?> getSerializer() {
		return serializer;
	}
	
	/**
	 * Sets the serializer for this PlanNode.
	 *
	 * @param serializer The serializer to set.
	 */
	public void setSerializer(TypeSerializerFactory<?> serializer) {
		this.serializer = serializer;
	}

	// --------------------------------------------------------------------------------------------
	

	@Override
	public void accept(Visitor<PlanNode> visitor) {
		if (visitor.preVisit(this)) {
			visitor.postVisit(this);
		}
	}


	@Override
	public Iterable<PlanNode> getPredecessors() {
		return Collections.<PlanNode>emptyList();
	}


	@Override
	public Iterable<Channel> getInputs() {
		return Collections.<Channel>emptyList();
	}


	@Override
	public SourceAndDamReport hasDamOnPathDownTo(PlanNode source) {
		if (source == this) {
			return FOUND_SOURCE;
		} else {
			return NOT_FOUND;
		}
	}
}