sgoeschl 2005/02/16 03:13:49
Added: yaafi/src/java/org/apache/fulcrum/yaafi/service/reconfiguration
ReconfigurationService.java
ReconfigurationServiceImpl.java
Log:
Initial import
Revision Changes Path
1.1
jakarta-turbine-fulcrum/yaafi/src/java/org/apache/fulcrum/yaafi/service/reconfiguration/ReconfigurationService.java
Index: ReconfigurationService.java
===================================================================
package org.apache.fulcrum.yaafi.service.reconfiguration;
/*
* Copyright 2004 Apache Software Foundation
* 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.
*/
/**
* Monitors the componentConfiguration.xml and triggers a reconfiguration
* if the content of the component configuration file has changed.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Siegfried Goeschl</a>
*/
public interface ReconfigurationService
{
// This interface doesn't exposes any other methods
}
1.1
jakarta-turbine-fulcrum/yaafi/src/java/org/apache/fulcrum/yaafi/service/reconfiguration/ReconfigurationServiceImpl.java
Index: ReconfigurationServiceImpl.java
===================================================================
package org.apache.fulcrum.yaafi.service.reconfiguration;
/*
* Copyright 2004 Apache Software Foundation
* 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.
*/
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.activity.Startable;
import org.apache.avalon.framework.activity.Suspendable;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.configuration.DefaultConfigurationBuilder;
import org.apache.avalon.framework.configuration.Reconfigurable;
import org.apache.avalon.framework.context.Context;
import org.apache.avalon.framework.context.ContextException;
import org.apache.avalon.framework.context.Contextualizable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.fulcrum.yaafi.framework.util.InputStreamLocator;
/**
* Monitors the componentConfiguration.xml and triggers a reconfiguration
* if the content of the component configuration file has changed.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Siegfried Goeschl</a>
*/
public class ReconfigurationServiceImpl
extends AbstractLogEnabled
implements ReconfigurationService, Serviceable, Contextualizable,
Configurable, Initializable, Runnable, Startable, Disposable
{
/** the interval between two checks in ms */
private int interval;
/** the location of the componentConfiguration file */
private String location;
/** helper for locating the component configuration */
private InputStreamLocator locator;
/** shall the worker thread terminate immediately */
private boolean terminateNow;
/** the worker thread polling the componentConfiguraton */
private Thread workerThread;
/** the ServiceManager to use */
private ServiceManager serviceManager;
/////////////////////////////////////////////////////////////////////////
// Avalon Service Lifecycle Implementation
/////////////////////////////////////////////////////////////////////////
/**
* Constructor
*/
public ReconfigurationServiceImpl()
{
// nothing to do
}
/**
* @see
org.apache.avalon.framework.service.Serviceable#service(org.apache.avalon.framework.service.ServiceManager)
*/
public void service(ServiceManager manager) throws ServiceException
{
this.serviceManager = manager;
}
/**
* @see
org.apache.avalon.framework.context.Contextualizable#contextualize(org.apache.avalon.framework.context.Context)
*/
public void contextualize(Context context) throws ContextException
{
this.locator = new InputStreamLocator( (File)
context.get("urn:avalon:home") );
}
/**
* @see
org.apache.avalon.framework.configuration.Configurable#configure(org.apache.avalon.framework.configuration.Configuration)
*/
public void configure(Configuration configuration) throws
ConfigurationException
{
this.interval = Math.max(
configuration.getAttributeAsInteger("interval",5000), 1000 );
this.location = configuration.getChild("location").getValue();
}
/**
* @see org.apache.avalon.framework.activity.Initializable#initialize()
*/
public void initialize() throws Exception
{
// ensure that we actually find our target
if( this.locate() == null )
{
String msg = "The component configuration was not found : " +
this.location;
this.getLogger().error(msg);
throw new IllegalArgumentException(msg);
}
else
{
String msg = "Checking " + this.location + " every " +
this.interval + " ms";
this.getLogger().debug( msg );
}
// request a SHA-1 to make sure that it is supported
MessageDigest.getInstance( "SHA1" );
// check that the ServiceManager inplements Reconfigurable
if( (this.serviceManager instanceof Reconfigurable) == false )
{
String msg = "The ServiceManager instance does not implement
Reconfigurable?!";
throw new IllegalArgumentException( msg );
}
// create the worker thread polling the target
this.workerThread = new Thread( this, "ReconfigurationService" );
}
/**
* @see org.apache.avalon.framework.activity.Startable#start()
*/
public void start() throws Exception
{
this.workerThread.start();
}
/**
* @see org.apache.avalon.framework.activity.Startable#stop()
*/
public void stop() throws Exception
{
this.terminateNow = true;
this.workerThread.interrupt();
this.workerThread.join( 10000 );
}
/**
* @see org.apache.avalon.framework.activity.Disposable#dispose()
*/
public void dispose()
{
this.locator = null;
this.workerThread = null;
this.serviceManager = null;
}
/////////////////////////////////////////////////////////////////////////
// Service interface implementation
/////////////////////////////////////////////////////////////////////////
/**
* @see java.lang.Runnable#run()
*/
public void run()
{
byte[] lastDigest = null;
byte[] currDigest = null;
InputStream is = null;
boolean isFirstInvocation = true;
while( this.terminateNow == false )
{
try
{
// get a grip on our file
is = this.locate();
if( is == null )
{
String msg = "Unable to find the component configuration";
this.getLogger().warn(msg);
continue;
}
// calculate a SHA-1 digest
currDigest = this.getDigest(is);
is.close();
is = null;
if( isFirstInvocation == true )
{
isFirstInvocation = false;
this.getLogger().debug( "Storing SHA-1 digest of
componentConfiguration" );
lastDigest = currDigest;
}
else
{
this.getLogger().debug( "Checking the
componentConfiguration to detect changes ..." );
if( equals( lastDigest, currDigest ) == false )
{
this.getLogger().debug( "The componentConfiguration
has changed" );
lastDigest = currDigest;
this.reconfigure();
}
Thread.sleep( this.interval );
}
}
catch( InterruptedException e )
{
continue;
}
catch(Exception e)
{
String msg = "The ReconfigurationService had a problem";
this.getLogger().error(msg,e);
continue;
}
finally
{
if( is != null )
{
try
{
is.close();
}
catch (Exception e)
{
String msg = "Can't close the InputStream during
error recovery";
this.getLogger().error(msg,e);
}
}
}
}
return;
}
/////////////////////////////////////////////////////////////////////////
// Service implementation
/////////////////////////////////////////////////////////////////////////
private void reconfigure() throws Exception
{
InputStream is = this.locate();
DefaultConfigurationBuilder builder = new
DefaultConfigurationBuilder();
Configuration configuration = builder.build(is);
is.close();
is = null;
this.getLogger().warn( "Starting to reconfigure the container" );
if( this.serviceManager instanceof Suspendable)
{
this.getLogger().info( "Calling suspend() of the container" );
((Suspendable) this.serviceManager).suspend();
}
if( this.serviceManager instanceof Reconfigurable)
{
this.getLogger().info( "Calling reconfigure() of the container" );
((Reconfigurable) this.serviceManager).reconfigure(configuration);
}
if( this.serviceManager instanceof Suspendable)
{
this.getLogger().info( "Calling resume() of the container" );
((Suspendable) this.serviceManager).resume();
}
this.getLogger().info( "Reconfiguring the container was successful" );
}
/**
* Creates an InputStream
*/
private InputStream locate() throws IOException
{
return this.locator.locate(this.location);
}
/**
* Pumps the input stream to the output stream.
*
* @param is the source input stream
* @param os the target output stream
* @throws IOException the copying failed
*/
private static void copy( InputStream is, OutputStream os )
throws IOException
{
byte[] buf = new byte[1024];
int n = 0;
int total = 0;
while ((n = is.read(buf)) > 0)
{
os.write(buf, 0, n);
total += n;
}
is.close();
os.flush();
os.close();
}
/**
* Creates a message digest
*/
private byte[] getDigest( InputStream is )
throws Exception
{
byte[] result = null;
byte[] content = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
copy( is, baos );
content = baos.toByteArray();
baos.close();
MessageDigest sha1 = MessageDigest.getInstance( "SHA1" );
sha1.update( content );
result = sha1.digest();
return result;
}
/**
* Compares two byte[] for equality
*/
private static boolean equals(byte[] lhs, byte[] rhs)
{
if( lhs == rhs )
{
return true;
}
else if( lhs.length != rhs.length )
{
return false;
}
else
{
for( int i=0; i<lhs.length; i++ )
{
if( lhs[i] != rhs[i] )
{
return false;
}
}
}
return true;
}
}
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