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 }