net.sf.ehcache.Status Maven / Gradle / Ivy

/**
 *  Copyright Terracotta, Inc.
 *
 *  Licensed 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 net.sf.ehcache;

import java.io.Serializable;

/**
 * A pre JDK1.5 compatible enum class to indicate the status of a {@link CacheManager} or {@link Cache}.
 * 
 * ehcache historically used int values for status. This is unsuitable for third party use thus this class.
 * Methods are provided to convert from the int status values to enum values and vice versa.
 *
 * @author Greg Luck
 * @version $Id: Status.java 5631 2012-05-10 08:31:33Z teck $
 * @since 1.2
 */
public final class Status implements Serializable {
    /**
     * The cache is uninitialised. It cannot be used.
     */
    public static final Status STATUS_UNINITIALISED = new Status(0, "STATUS_UNINITIALISED");
    /**
     * The cache is alive. It can be used.
     */
    public static final Status STATUS_ALIVE = new Status(1, "STATUS_ALIVE");
    /**
     * The cache is shudown. It cannot be used.
     */
    public static final Status STATUS_SHUTDOWN = new Status(2, "STATUS_SHUTDOWN");

    private static final long serialVersionUID = 2732730630423367732L;

    private static final Status[] STATUSES = {STATUS_UNINITIALISED, STATUS_ALIVE, STATUS_SHUTDOWN};

    private final String name;
    private final int intValue;

    private Status(int intValue, String name) {
        this.intValue = intValue;
        this.name = name;

    }

    /**
     * Returns a string representation of the object. In general, the
     * toString method returns a string that
     * "textually represents" this object. The result should
     * be a concise but informative representation that is easy for a
     * person to read.
     * It is recommended that all subclasses override this method.
     * 

     * The toString method for class Object
     * returns a string consisting of the name of the class of which the
     * object is an instance, the at-sign character `@', and
     * the unsigned hexadecimal representation of the hash code of the
     * object. In other words, this method returns a string equal to the
     * value of:
     * 

     *      * getClass().getName() + '@' + Integer.toHexString(hashCode())
     * 
     *
     * @return a string representation of the object.
     */
    public String toString() {
        return name;
    }

    /**
     * @param statusAsInt an int argument between 1 and 3.
     * @return an enum Status
     * @throws IllegalArgumentException if the argument is not between 1 and 3
     */
    public static Status convertIntToStatus(int statusAsInt) throws IllegalArgumentException {
        if ((statusAsInt < STATUS_UNINITIALISED.intValue) || (statusAsInt > STATUS_SHUTDOWN.intValue)) {
            throw new IllegalArgumentException("int value of statuses must be between 1 and three");
        }
        return STATUSES[statusAsInt];
    }

    /**
     * Returns the int value of status, for backward compatibility with ehcache versions below 1.2
     * @return the int value of this status.
     */
    public int intValue() {
        return intValue;
    }

    /**
     * Indicates whether some other object is "equal to" this one.
     * 
     * The equals method implements an equivalence relation
     * on non-null object references:
     * 

     * It is reflexive: for any non-null reference value
     * x, x.equals(x) should return
     * true.
     * 
It is symmetric: for any non-null reference values
     * x and y, x.equals(y)
     * should return true if and only if
     * y.equals(x) returns true.
     * 
It is transitive: for any non-null reference values
     * x, y, and z, if
     * x.equals(y) returns true and
     * y.equals(z) returns true, then
     * x.equals(z) should return true.
     * 
It is consistent: for any non-null reference values
     * x and y, multiple invocations of
     * x.equals(y) consistently return true
     * or consistently return false, provided no
     * information used in equals comparisons on the
     * objects is modified.
     * 
For any non-null reference value x,
     * x.equals(null) should return false.
     * 
     * 
     * The equals method for class Object implements
     * the most discriminating possible equivalence relation on objects;
     * that is, for any non-null reference values x and
     * y, this method returns true if and only
     * if x and y refer to the same object
     * (x == y has the value true).
     * 
     * Note that it is generally necessary to override the hashCode
     * method whenever this method is overridden, so as to maintain the
     * general contract for the hashCode method, which states
     * that equal objects must have equal hash codes.
     *
     * @param object the reference object with which to compare.
     * @return true if this object is the same as the obj
     *         argument; false otherwise.
     * @see #hashCode()
     * @see java.util.Hashtable
     */
    public boolean equals(Object object) {
        if (!(object instanceof Status)) {
            return false;
        }
        return ((Status) object).intValue == intValue;
    }

    /**
     * Equality checker when the comparison object is of the same type.
     * @param status the status to check
     * @return true is the statuses are the same
     */
    public boolean equals(Status status) {
        if (status == null) {
            return false;
        } else {
            return (intValue == status.intValue);
        }
    }

    /**
     * Returns a hash code value for Status. It is the underlying int value of the status.
     * @return a hash code value for this object.
     * @see Object#hashCode()
     * @see java.util.Hashtable
     */
    public int hashCode() {
        return intValue;
    }

}