/**
 * 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.yarn.api.records;

import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.classification.InterfaceStability.Stable;
import org.apache.hadoop.yarn.api.AMRMProtocol;

/**
 * <p><code>Resource</code> models a set of computer resources in the 
 * cluster.</p>
 * 
 * <p>Currrently it only models <em>memory</em>.</p>
 * 
 * <p>Typically, applications request <code>Resource</code> of suitable
 * capability to run their component tasks.</p>
 * 
 * @see ResourceRequest
 * @see AMRMProtocol#allocate(org.apache.hadoop.yarn.api.protocolrecords.AllocateRequest)
 */
@Public
@Stable
public abstract class Resource implements Comparable<Resource> {

  /**
   * Get <em>memory</em> of the resource.
   * @return <em>memory</em> of the resource
   */
  @Public
  @Stable
  public abstract int getMemory();
  
  /**
   * Set <em>memory</em> of the resource.
   * @param memory <em>memory</em> of the resource
   */
  @Public
  @Stable
  public abstract void setMemory(int memory);

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + getMemory();
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    Resource other = (Resource) obj;
    if (getMemory() != other.getMemory())
      return false;
    return true;
  }

  @Override
  public String toString() {
    return "memory: " + getMemory();
  }
}