Source code

001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.wake;
020
021/**
022 * An identifier class for REEF.  Identifiers are a generic naming primitive
023 * that carry some information about the type of the object they point to.
024 * Typical examples are server sockets, filenames, and requests.
025 *
026 * Identifier constructors should take zero arguments, or take a single string.
027 */
028public interface Identifier {
029
030  /**
031   * Returns a hash code for the object.
032   *
033   * @return a hash code value for this object
034   */
035  int hashCode();
036
037  /**
038   * Checks that another object is equal to this object.
039   *
040   * @param o another object
041   * @return true if the object is the same as the object argument; false,
042   * otherwise
043   */
044  boolean equals(Object o);
045
046  /**
047   * Return a string representation of this object. This method should return a
048   * URL-style string, that begins with "type://", where "type" is chosen to
049   * uniquely identify this type of identifier.
050   */
051  String toString();
052
053}