src.gov.nasa.worldwind.util.SessionCacheRetrievalPostProcessor Maven / Gradle / Ivy
/*
* Copyright (C) 2012 United States Government as represented by the Administrator of the
* National Aeronautics and Space Administration.
* All Rights Reserved.
*/
package gov.nasa.worldwind.util;
import gov.nasa.worldwind.cache.SessionCache;
import gov.nasa.worldwind.retrieve.*;
import java.beans.*;
/**
* SessionCache inspects the results of a retrieval for success or failure. If the retrieval succeeded, this places the
* retrieved data in a specified session cache with a specified cache key, and marks the resource as available. If the
* retrieval failed, this logs the cause and marks the resource as missing. Finally, this optionally fires a property
* change event signalling that the retrieval is complete.
*
* @author dcollins
* @version $Id: SessionCacheRetrievalPostProcessor.java 1171 2013-02-11 21:45:02Z dcollins $
*/
public class SessionCacheRetrievalPostProcessor implements RetrievalPostProcessor
{
private String name;
private final SessionCache cache;
private final Object cacheKey;
private final AbsentResourceList absentResourceList;
private final long resourceID;
private final PropertyChangeListener propertyListener;
private final String propertyName;
/**
* Constructs a SessionCachePostProcessor with a specified cache and cache key, and an optional property listener
* and property name.
*
* @param cache cache that receives the retrieved data.
* @param cacheKey cache key to place the retrieved data under.
* @param absentResourceList the absent resource list to update.
* @param resourceID the resource ID to use in the absent resource list.
* @param propertyListener property listener to notify when the data is available. Can be null.
* @param propertyName property name to use for the property event when the data is available. Can be null.
*/
public SessionCacheRetrievalPostProcessor(SessionCache cache, Object cacheKey,
AbsentResourceList absentResourceList, long resourceID,
PropertyChangeListener propertyListener, String propertyName)
{
if (cache == null)
{
String message = Logging.getMessage("nullValue.CacheIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
if (cacheKey == null)
{
String message = Logging.getMessage("nullValue.CacheKeyIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
this.cache = cache;
this.cacheKey = cacheKey;
this.absentResourceList = absentResourceList;
this.resourceID = resourceID;
this.propertyListener = propertyListener;
this.propertyName = propertyName;
}
/**
* Returns this post processor's name, or null if this post processor doesn't have a name.
*
* @return this post processor's name. May be null.
*/
public String getName()
{
return this.name;
}
/**
* Sets this post processor's name to a specified String value, or null to specify that the post processor does not
* have a name.
*
* @param name this post processor's name. May be null.
*/
public void setName(String name)
{
this.name = name;
}
/**
* Returns the session cache that receives the retrieved data.
*
* @return the session cache that receives data.
*/
public final SessionCache getCache()
{
return this.cache;
}
/**
* Returns the cache key which identifies where the retrieved data is placed in the session cache.
*
* @return cache key for the retrieved data.
*/
public final Object getCacheKey()
{
return this.cacheKey;
}
/**
* Returns the absent resource list that is updated when the retrieval completes.
*
* @return the absent resource list.
*/
public final AbsentResourceList getAbsentResourceList()
{
return this.absentResourceList;
}
/**
* Returns the resource ID to use in the absent resource list.
*
* @return resource ID to use in the absent resource list.
*/
public final long getResourceID()
{
return this.resourceID;
}
/**
* Returns the property change listener which is fired when the retrieved data is available. A null value indicates
* that no property event is fired.
*
* @return property change listener to fire when retrieved data is available.
*/
public final PropertyChangeListener getPropertyListener()
{
return this.propertyListener;
}
/**
* Returns the property name to use in the property change event fired when retrieved data is available. A null
* value indicates that no property event is fired.
*
* @return property name to fire when retrieved data is available.
*/
public final String getPropertyName()
{
return this.propertyName;
}
/**
* Inspect the results of a retrieval for success or failure. If the retrieval succeeded, this places the retrieved
* data in the session cache with the specified cache key and marks the resource as available. If the retrieval
* failed, this logs the cause and marks the resource as missing. Finally, this optionally fires a property change
* event signalling that the retrieval is complete.
*
* @param retriever the Retriever which has either succeeded or failed in fetching the data.
*
* @return the retrieved data.
*/
public java.nio.ByteBuffer run(Retriever retriever)
{
if (retriever == null)
{
String message = Logging.getMessage("nullValue.RetrieverIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
String message = this.validate(retriever);
if (message == null)
{
this.onRetrievalSuceeded(retriever);
}
else
{
this.onRetrievalFailed(retriever);
Logging.logger().severe(message);
}
this.signalRetrievalComplete();
return retriever.getBuffer();
}
protected void onRetrievalSuceeded(Retriever retriever)
{
// Put the retrieved data in the session cache, using the specified cache key.
if (this.absentResourceList != null)
this.absentResourceList.unmarkResourceAbsent(this.resourceID);
this.cache.put(this.cacheKey, retriever.getBuffer());
}
@SuppressWarnings({"UnusedDeclaration"})
protected void onRetrievalFailed(Retriever retriever)
{
if (this.absentResourceList != null)
this.absentResourceList.markResourceAbsent(this.resourceID);
}
protected String validate(Retriever retriever)
{
if (!retriever.getState().equals(Retriever.RETRIEVER_STATE_SUCCESSFUL))
return Logging.getMessage("generic.RetrievalFailed", this.toString());
if (retriever.getBuffer() == null || retriever.getBuffer().limit() == 0)
return Logging.getMessage("generic.RetrievalReturnedNoContent", this.toString());
return null;
}
protected void signalRetrievalComplete()
{
// If both the property listener and property name are non-null, then fire a property change event,
// signalling that the retrieval has completed.s
if (this.propertyListener != null && this.propertyName != null)
{
this.propertyListener.propertyChange(
new PropertyChangeEvent(this, this.propertyName, null, this.propertyListener));
}
}
/**
* If the post processor has a non-null String name, this returns that name. Otherwise, this returns the superclass'
* toString().
*
* @return String representation of this post processor.
*/
public String toString()
{
if (this.getName() != null)
return this.getName();
return super.toString();
}
}