mcconnell 02/02/21 08:31:08
Added: src/java/org/apache/avalon/framework/service
DefaultServiceSelector.java
Log:
initial implementation of ServiceSelector
Revision Changes Path
1.1
jakarta-avalon/src/java/org/apache/avalon/framework/service/DefaultServiceSelector.java
Index: DefaultServiceSelector.java
===================================================================
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
package org.apache.avalon.framework.service;
import java.util.HashMap;
import java.util.Map;
/**
* This is the default implementation of the ServiceSelector
*
* @author <a href="mailto:[EMAIL PROTECTED]">Berin Loritsch</a>
* @author <a href="mailto:[EMAIL PROTECTED]">Stephen McConnell</a>
*/
public class DefaultServiceSelector
implements ServiceSelector
{
private final HashMap m_objects = new HashMap();
private boolean m_readOnly;
/**
* Select the desired object.
*
* @param hint the hint to retrieve Object
* @return the Object
* @exception ServiceException if an error occurs
*/
public Object select( Object hint )
throws ServiceException
{
final Object object = m_objects.get( hint );
if( null != object )
{
return object;
}
else
{
throw new ServiceException( "Unable to provide implementation for
" +
hint.toString() );
}
}
/**
* Returns whether a Object exists or not
*/
public boolean isSelectable( final Object hint ) {
boolean objectExists = false;
try
{
this.release(this.select(hint));
objectExists = true;
}
catch (Throwable t)
{
// Ignore all throwables--we want a yes or no answer.
}
return objectExists;
}
/**
* Release object.
*
* @param <code>Object</code> the object to release
*/
public void release( final Object object )
{
// if the ServiceManager handled pooling, it would be
// returned to the pool here.
}
/**
* Populate the ServiceSelector.
*/
public void put( final Object hint, final Object object )
{
checkWriteable();
m_objects.put( hint, object );
}
/**
* Helper method for subclasses to retrieve object map.
*
* @return the object map
*/
protected final Map getObjectMap()
{
return m_objects;
}
public void makeReadOnly()
{
m_readOnly = true;
}
protected final void checkWriteable()
throws IllegalStateException
{
if( m_readOnly )
{
throw new IllegalStateException( "ServiceSelector is read only
and can not be modified" ); }
}
}
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