/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.util;
import java.lang.ref.SoftReference;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import org.jboss.logging.Logger;
import org.jboss.util.collection.ConcurrentReferenceHashMap;
/**
* Utility Class
*
* Utility Class that provides a Logger instance (log) and
* caching of toString() and hashCode() values.
*
* You most probably want to override the method that
* comes from JBossInterface:
*
* public void toShortString(StringBuffer buffer)
*
* to append to the buffer the key class properties, and
* also override the following methods to provide the
* hashCode and the class properties that should be cached:
*
* protected void toString(StringBuffer buffer)
* protected int getHashCode()
*
* Cached values can be flushed using flushJBossObjectCache()
*
* Caching can be disabled by simply overriding toString()
* and hashCode(), or returning false from methods:
*
* protected boolean cacheToString()
* protected boolean cacheGetHashCode()
*
* @author <a href="adrian@jboss.com">Adrian Brock</a>
* @author <a href="ales.justin@jboss.com">Ales Justin</a>
* @version $Revision: 3505 $
*/
@SuppressWarnings("unchecked")
public class JBossObject implements JBossInterface
{
/** The loggers */
private static final Map<Class<?>, Logger> loggers = new ConcurrentReferenceHashMap<Class<?>, Logger>();
/** The log */
protected Logger log;
/** Cached toString */
protected transient SoftReference toString;
/** Cached hashCode */
protected transient int hashCode = Integer.MIN_VALUE;
/**
* Create a new object
*/
public JBossObject()
{
log = createLog();
}
/**
* Create a new object using the specified Logger instace
*
* @param log the Logger instance to use
*/
public JBossObject(Logger log)
{
this.log = (log != null) ? log : createLog();
}
/**
* Create logger.
*
* @return the logger
*/
private Logger createLog()
{
Class<?> clazz = getClass();
Logger logger = loggers.get(clazz);
if (logger == null)
{
logger = Logger.getLogger(clazz);
loggers.put(clazz, logger);
}
return logger;
}
/**
* Safe equality check
*
* @param one an object
* @param two another object
* @return true when they are equal
*/
public static boolean equals(Object one, Object two)
{
if (one == null && two != null)
return false;
if (one != null && one.equals(two) == false)
return false;
return true;
}
/**
* Safe inequality check
*
* @param one an object
* @param two another object
* @return true when they are not equal
*/
public static boolean notEqual(Object one, Object two)
{
return equals(one, two) == false;
}
/**
* List the set of JBossObjects
*
* @param buffer the buffer
* @param objects the collection of objects
*/
public static void list(JBossStringBuilder buffer, Collection objects)
{
if (objects == null)
return;
buffer.append('[');
if (objects.isEmpty() == false)
{
for (Iterator i = objects.iterator(); i.hasNext();)
{
Object object = i.next();
if (object instanceof JBossObject)
((JBossObject) object).toShortString(buffer);
else
buffer.append(object.toString());
if (i.hasNext())
buffer.append(", ");
}
}
buffer.append(']');
}
/**
* Override toString to cache the value
*
* @return the String
*/
public String toString()
{
if (cacheToString() == false)
return toStringImplementation();
String result = null;
if (toString != null)
result = (String) toString.get();
if (result == null)
{
result = toStringImplementation();
toString = new SoftReference(result);
}
return result;
}
/**
* Override hashCode to cache the value
*
* @return the hashCode
*/
public int hashCode()
{
if (hashCode == Integer.MIN_VALUE || cacheGetHashCode() == false)
hashCode = getHashCode();
return hashCode;
}
public Object clone()
{
try
{
return super.clone();
}
catch (CloneNotSupportedException e)
{
throw new RuntimeException(e);
}
}
public String toShortString()
{
JBossStringBuilder buffer = new JBossStringBuilder();
toShortString(buffer);
return buffer.toString();
}
/**
* Append the key class properties to the buffer
*
* @param buffer the buffer
*/
public void toShortString(JBossStringBuilder buffer)
{
}
/**
* Get the class short name
*
* @return the short name of the class
*/
public String getClassShortName()
{
String longName = getClass().getName();
int dot = longName.lastIndexOf('.');
if (dot != -1)
return longName.substring(dot + 1);
return longName;
}
/**
* Implementation of String
*
* @return the string
*/
protected String toStringImplementation()
{
JBossStringBuilder buffer = new JBossStringBuilder();
buffer.append(getClassShortName()).append('@');
buffer.append(Integer.toHexString(System.identityHashCode(this)));
buffer.append('{');
toString(buffer);
buffer.append('}');
return buffer.toString();
}
/**
* Flush the JBossObject cached values
*/
protected void flushJBossObjectCache()
{
toString = null;
hashCode = Integer.MIN_VALUE;
}
/**
* Append the class properties to the buffer
*
* @param buffer the buffer
*/
protected void toString(JBossStringBuilder buffer)
{
}
/**
* Calculate the hashcode
*
* @return the hash code
*/
protected int getHashCode()
{
return super.hashCode();
}
/**
* Whether we should cache the result toString()
*
* @return true by default
*/
protected boolean cacheToString()
{
return true;
}
/**
* Whether we should cache the result hashCode()
*
* @return true by default
*/
protected boolean cacheGetHashCode()
{
return true;
}
}