1 /** 2 * Copyright 2003-2006 Greg Luck 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package net.sf.ehcache; 18 19 import java.io.Serializable; 20 21 /** 22 * A pre JDK1.5 compatible enum class to indicate the status of a {@link CacheManager} or {@link Cache}. 23 * <p/> 24 * ehcache historically used int values for status. This is unsuitable for third party use thus this class. 25 * Methods are provided to convert from the int status values to enum values and vice versa. 26 * 27 * @author Greg Luck 28 * @version $Id: Status.java 52 2006-04-24 14:50:03Z gregluck $ 29 * @since 1.2 30 * @noinspection SerializableHasSerializationMethods 31 */ 32 public final class Status implements Serializable { 33 /** 34 * The cache is uninitialised. It cannot be used. 35 */ 36 public static final Status STATUS_UNINITIALISED = new Status(0, "STATUS_UNINITIALISED"); 37 /** 38 * The cache is alive. It can be used. 39 */ 40 public static final Status STATUS_ALIVE = new Status(1, "STATUS_ALIVE"); 41 /** 42 * The cache is shudown. It cannot be used. 43 */ 44 public static final Status STATUS_SHUTDOWN = new Status(2, "STATUS_SHUTDOWN"); 45 46 private static final long serialVersionUID = 2732730630423367732L; 47 48 private static final Status[] STATUSES = {STATUS_UNINITIALISED, STATUS_ALIVE, STATUS_SHUTDOWN}; 49 50 private final String name; 51 private final int intValue; 52 53 private Status(int intValue, String name) { 54 this.intValue = intValue; 55 this.name = name; 56 57 } 58 59 /** 60 * Returns a string representation of the object. In general, the 61 * <code>toString</code> method returns a string that 62 * "textually represents" this object. The result should 63 * be a concise but informative representation that is easy for a 64 * person to read. 65 * It is recommended that all subclasses override this method. 66 * <p/> 67 * The <code>toString</code> method for class <code>Object</code> 68 * returns a string consisting of the name of the class of which the 69 * object is an instance, the at-sign character `<code>@</code>', and 70 * the unsigned hexadecimal representation of the hash code of the 71 * object. In other words, this method returns a string equal to the 72 * value of: 73 * <blockquote> 74 * <pre> 75 * getClass().getName() + '@' + Integer.toHexString(hashCode()) 76 * </pre></blockquote> 77 * 78 * @return a string representation of the object. 79 */ 80 public String toString() { 81 return name; 82 } 83 84 /** 85 * @param statusAsInt an int argument between 1 and 3. 86 * @return an enum Status 87 * @throws IllegalArgumentException if the argument is not between 1 and 3 88 */ 89 public static Status convertIntToStatus(int statusAsInt) throws IllegalArgumentException { 90 if ((statusAsInt < STATUS_UNINITIALISED.intValue) || (statusAsInt > STATUS_SHUTDOWN.intValue)) { 91 throw new IllegalArgumentException("int value of statuses must be between 1 and three"); 92 } 93 return STATUSES[statusAsInt]; 94 } 95 96 /** 97 * Returns the int value of status, for backward compatibility with ehcache versions below 1.2 98 * @return the int value of this status. 99 */ 100 public int intValue() { 101 return intValue; 102 } 103 104 /** 105 * Indicates whether some other object is "equal to" this one. 106 * <p/> 107 * The <code>equals</code> method implements an equivalence relation 108 * on non-null object references: 109 * <ul> 110 * <li>It is <i>reflexive</i>: for any non-null reference value 111 * <code>x</code>, <code>x.equals(x)</code> should return 112 * <code>true</code>. 113 * <li>It is <i>symmetric</i>: for any non-null reference values 114 * <code>x</code> and <code>y</code>, <code>x.equals(y)</code> 115 * should return <code>true</code> if and only if 116 * <code>y.equals(x)</code> returns <code>true</code>. 117 * <li>It is <i>transitive</i>: for any non-null reference values 118 * <code>x</code>, <code>y</code>, and <code>z</code>, if 119 * <code>x.equals(y)</code> returns <code>true</code> and 120 * <code>y.equals(z)</code> returns <code>true</code>, then 121 * <code>x.equals(z)</code> should return <code>true</code>. 122 * <li>It is <i>consistent</i>: for any non-null reference values 123 * <code>x</code> and <code>y</code>, multiple invocations of 124 * <tt>x.equals(y)</tt> consistently return <code>true</code> 125 * or consistently return <code>false</code>, provided no 126 * information used in <code>equals</code> comparisons on the 127 * objects is modified. 128 * <li>For any non-null reference value <code>x</code>, 129 * <code>x.equals(null)</code> should return <code>false</code>. 130 * </ul> 131 * <p/> 132 * The <tt>equals</tt> method for class <code>Object</code> implements 133 * the most discriminating possible equivalence relation on objects; 134 * that is, for any non-null reference values <code>x</code> and 135 * <code>y</code>, this method returns <code>true</code> if and only 136 * if <code>x</code> and <code>y</code> refer to the same object 137 * (<code>x == y</code> has the value <code>true</code>). 138 * <p/> 139 * Note that it is generally necessary to override the <tt>hashCode</tt> 140 * method whenever this method is overridden, so as to maintain the 141 * general contract for the <tt>hashCode</tt> method, which states 142 * that equal objects must have equal hash codes. 143 * 144 * @param object the reference object with which to compare. 145 * @return <code>true</code> if this object is the same as the obj 146 * argument; <code>false</code> otherwise. 147 * @see #hashCode() 148 * @see java.util.Hashtable 149 */ 150 public boolean equals(Object object) { 151 if (!(object instanceof Status)) { 152 return false; 153 } 154 return ((Status) object).intValue == intValue; 155 } 156 157 /** 158 * Equality checker when the comparison object is of the same type. 159 * @param status the status to check 160 * @return true is the statuses are the same 161 */ 162 public boolean equals(Status status) { 163 return intValue == status.intValue; 164 } 165 166 /** 167 * Returns a hash code value for the object. This method is 168 * supported for the benefit of hashtables such as those provided by 169 * <code>java.util.Hashtable</code>. 170 * <p/> 171 * The general contract of <code>hashCode</code> is: 172 * <ul> 173 * <li>Whenever it is invoked on the same object more than once during 174 * an execution of a Java application, the <tt>hashCode</tt> method 175 * must consistently return the same integer, provided no information 176 * used in <tt>equals</tt> comparisons on the object is modified. 177 * This integer need not remain consistent from one execution of an 178 * application to another execution of the same application. 179 * <li>If two objects are equal according to the <tt>equals(Object)</tt> 180 * method, then calling the <code>hashCode</code> method on each of 181 * the two objects must produce the same integer result. 182 * <li>It is <em>not</em> required that if two objects are unequal 183 * according to the {@link Object#equals(Object)} 184 * method, then calling the <tt>hashCode</tt> method on each of the 185 * two objects must produce distinct integer results. However, the 186 * programmer should be aware that producing distinct integer results 187 * for unequal objects may improve the performance of hashtables. 188 * </ul> 189 * <p/> 190 * As much as is reasonably practical, the hashCode method defined by 191 * class <tt>Object</tt> does return distinct integers for distinct 192 * objects. (This is typically implemented by converting the internal 193 * address of the object into an integer, but this implementation 194 * technique is not required by the 195 * Java<font size="-2"><sup>TM</sup></font> programming language.) 196 * 197 * @return a hash code value for this object. 198 * @see Object#equals(Object) 199 * @see java.util.Hashtable 200 */ 201 public int hashCode() { 202 return intValue; 203 } 204 205 }