/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.collections;
import com.google.common.base.Preconditions;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.concurrent.NotThreadSafe;
/**
* A Directed Acyclic Graph (DAG) node.
*
* @param <T> payload
*/
@NotThreadSafe
public class DirectedAcyclicGraphNode<T> {
private final T mPayload;
private final List<DirectedAcyclicGraphNode<T>> mParents;
private final List<DirectedAcyclicGraphNode<T>> mChildren;
/**
* A Directed Acyclic Graph (DAG) node.
*
* @param payload the payload of the node
* @param parents the parents of the node
* @param children the children of the node
*/
public DirectedAcyclicGraphNode(T payload, List<DirectedAcyclicGraphNode<T>> parents,
List<DirectedAcyclicGraphNode<T>> children) {
mPayload = Preconditions.checkNotNull(payload, "payload");
mParents = Preconditions.checkNotNull(parents, "parents");
mChildren = Preconditions.checkNotNull(children, "children");
}
/**
* A Directed Acyclic Graph (DAG) node.
*
* @param payload the payload of the node
*/
public DirectedAcyclicGraphNode(T payload) {
this(payload, new ArrayList<DirectedAcyclicGraphNode<T>>(),
new ArrayList<DirectedAcyclicGraphNode<T>>());
}
/**
* Gets the payload of the node.
*
* @return the payload of the node
*/
public T getPayload() {
return mPayload;
}
/**
* Gets the parent nodes of the node.
*
* @return the parents of the node
*/
public List<DirectedAcyclicGraphNode<T>> getParents() {
return mParents;
}
/**
* Gets the children nodes of the node.
*
* @return the children of the node
*/
public List<DirectedAcyclicGraphNode<T>> getChildren() {
return mChildren;
}
/**
* Adds a parent node to the node.
*
* @param parent the node to be added as a parent
*/
public void addParent(DirectedAcyclicGraphNode<T> parent) {
mParents.add(parent);
}
/**
* Adds a child node to the node.
*
* @param child the node to be added as a child
*/
public void addChild(DirectedAcyclicGraphNode<T> child) {
mChildren.add(child);
}
/**
* Removes a child node from the node.
*
* @param child the child node to be removed
*/
public void removeChild(DirectedAcyclicGraphNode<T> child) {
Preconditions.checkState(mChildren.contains(child));
mChildren.remove(child);
}
}