/**
* 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.hadoop.tools.rumen;
import java.util.Set;
import java.util.Random;
/**
* {@link ClusterStory} represents all configurations of a MapReduce cluster,
* including nodes, network topology, and slot configurations.
*/
public interface ClusterStory {
/**
* Get all machines of the cluster.
* @return A read-only set that contains all machines of the cluster.
*/
public Set<MachineNode> getMachines();
/**
* Get all racks of the cluster.
* @return A read-only set that contains all racks of the cluster.
*/
public Set<RackNode> getRacks();
/**
* Get the cluster topology tree.
* @return The root node of the cluster topology tree.
*/
public Node getClusterTopology();
/**
* Select a random set of machines.
* @param expected The expected sample size.
* @param random Random number generator to use.
* @return An array of up to expected number of {@link MachineNode}s.
*/
public MachineNode[] getRandomMachines(int expected, Random random);
/**
* Get {@link MachineNode} by its host name.
*
* @return The {@link MachineNode} with the same name. Or null if not found.
*/
public MachineNode getMachineByName(String name);
/**
* Get {@link RackNode} by its name.
* @return The {@link RackNode} with the same name. Or null if not found.
*/
public RackNode getRackByName(String name);
/**
* Determine the distance between two {@link Node}s. Currently, the distance
* is loosely defined as the length of the longer path for either a or b to
* reach their common ancestor.
*
* @param a
* @param b
* @return The distance between {@link Node} a and {@link Node} b.
*/
int distance(Node a, Node b);
/**
* Get the maximum distance possible between any two nodes.
* @return the maximum distance possible between any two nodes.
*/
int getMaximumDistance();
}