/**
* Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information regarding copyright ownership. Apereo
* 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 the
* following location:
*
* <p>http://www.apache.org/licenses/LICENSE-2.0
*
* <p>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.apereo.portal.concurrency.locking;
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.persistence.TableGenerator;
import javax.persistence.Version;
import org.apache.commons.lang.Validate;
import org.hibernate.annotations.NaturalId;
import org.hibernate.annotations.NaturalIdCache;
import org.springframework.util.Assert;
/**
* Used to coordinate cluster wide locking via the database. Tracks the server that currently owns
* the lock, when the lock started, last updated and released.
*
*/
@Entity
@Table(name = "UP_MUTEX")
@SequenceGenerator(name = "UP_MUTEX_GEN", sequenceName = "UP_MUTEX_SEQ", allocationSize = 1)
@TableGenerator(name = "UP_MUTEX_GEN", pkColumnValue = "UP_MUTEX_PROP", allocationSize = 1)
//THIS CLASS CANNOT BE CACHED
@NaturalIdCache(region = "org.apereo.portal.concurrency.locking.ClusterMutex-NaturalId")
public class ClusterMutex implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(generator = "UP_MUTEX_GEN")
@Column(name = "MUTEX_ID")
private final long id;
@Version
@Column(name = "ENTITY_VERSION")
private final long entityVersion;
@NaturalId
@Column(name = "MUTEX_NAME", length = 200, nullable = false)
private final String name;
@Column(name = "LOCKED", nullable = false)
private boolean locked = false;
@Column(name = "SERVER_ID", length = 200)
private String serverId;
@Column(name = "PREV_SERVER_ID", length = 200)
private String previousServerId;
@Column(name = "LOCK_START", nullable = false)
private Date lockStart = new Date(0);
@Column(name = "LOCK_UPDATE", nullable = false)
private Date lastUpdate = new Date(0);
@Column(name = "LOCK_END", nullable = false)
private Date lockEnd = new Date(0);
@SuppressWarnings("unused")
private ClusterMutex() {
this.id = -1;
this.entityVersion = -1;
this.name = null;
}
ClusterMutex(String name) {
Validate.notNull(name, "name");
this.id = -1;
this.entityVersion = 0;
this.name = name;
}
/** @return the id */
public long getId() {
return this.id;
}
/** @return the name */
public String getName() {
return this.name;
}
/** @return If the lock is currently held */
public boolean isLocked() {
return this.locked;
}
/** @return the serverId that currently owns the lock, null if the mutex is not locked */
public String getServerId() {
return this.serverId;
}
/**
* @return the serverId of the previous lock owner, null if the mutex has never been locked or
* is locked for the first time
*/
public String getPreviousServerId() {
return this.previousServerId;
}
/** @return the lockStart */
public long getLockStart() {
return this.lockStart.getTime();
}
/** @return the lastUpdate */
public long getLastUpdate() {
return this.lastUpdate.getTime();
}
/** @return the lockEnd */
public long getLockEnd() {
return this.lockEnd.getTime();
}
/** Mark the mutex as locked by the specific server */
void lock(String serverId) {
Assert.notNull(serverId);
if (this.locked) {
throw new IllegalStateException("Cannot lock already locked mutex: " + this);
}
this.locked = true;
this.lockStart = new Date();
this.lastUpdate = this.lockStart;
this.serverId = serverId;
}
void unlock() {
if (!this.locked) {
throw new IllegalStateException("Cannot unlock already unlocked mutex: " + this);
}
this.locked = false;
this.lockEnd = new Date();
this.previousServerId = this.serverId;
this.serverId = null;
}
/** @param lastUpdate the lastUpdate to set */
void updateLock() {
this.lastUpdate = new Date();
}
/* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((this.name == null) ? 0 : this.name.hashCode());
return result;
}
/* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
ClusterMutex other = (ClusterMutex) obj;
if (this.name == null) {
if (other.name != null) return false;
} else if (!this.name.equals(other.name)) return false;
return true;
}
@Override
public String toString() {
return "ClusterMutex [name="
+ name
+ ", locked="
+ locked
+ ", serverId="
+ serverId
+ ", previousServerId="
+ previousServerId
+ ", lockStart="
+ lockStart
+ ", lastUpdate="
+ lastUpdate
+ ", lockEnd="
+ lockEnd
+ "]";
}
}