/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2011, Open Source Geospatial Foundation (OSGeo)
*
* This library 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;
* version 2.1 of the License.
*
* This library 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.
*/
package org.geotools.data.efeature;
import java.awt.RenderingHints.Key;
import java.lang.ref.WeakReference;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;
import javax.imageio.spi.ServiceRegistry;
import org.geotools.data.efeature.impl.EFeatureContextImpl;
import org.geotools.data.efeature.impl.EFeatureIDFactoryImpl;
import org.geotools.factory.BufferedFactory;
import org.geotools.util.logging.Logging;
/**
* This class implements a cache of {@link EFeatureContext} instances.
* <p>
* Each {@link EFeatureContext instance} is associated with a factory ID. The
* reference to each cached {@link EFeatureContext is} is strong (ordinary Java
* object reference), ensuring that instances can not be garbage collected, even
* if more memory is needed.
* </p>
*
* @author kengu
*
*
* @source $URL$
*/
public class EFeatureContextFactory implements BufferedFactory {
/**
* Cached {@link Logger} instance for this class
*/
private static final Logger LOGGER = Logging.getLogger(EFeatureContextFactory.class);
/**
* Weak reference to instance cached by the
* {@link ServiceRegistry service registry}.
*/
private static WeakReference<EFeatureContextFactory> eInstance;
/**
* {@link Map} containing {@link EFeatureContext} instances.
*/
private final Map<String, EFeatureContext>
eContextMap = new HashMap<String, EFeatureContext>();
/**
* {@link Map} containing {@link EFeatureContextInfo} instances.
*/
private final Map<String, EFeatureContextInfo>
eContextInfoMap = new HashMap<String, EFeatureContextInfo>();
// -----------------------------------------------------
// Constructors
// -----------------------------------------------------
/**
* Default construction (required by SPI)
*/
public EFeatureContextFactory() { /*NOP*/ }
// -----------------------------------------------------
// Static helper methods
// -----------------------------------------------------
/**
* Get instance cached by {@link EFeatureFactoryFinder}
*/
public static EFeatureContextFactory eDefault(){
if(eInstance==null || eInstance.get()==null)
{
eInstance = new WeakReference<EFeatureContextFactory>(
EFeatureFactoryFinder.getContextFactory());
}
return eInstance.get();
}
/**
* Check to see if {@link EFeatureDataStore}s can be created.
* <p>
* This factory is only available if at least one
* {@link EFeatureContext} instance is registered.
* <p>
*
* @return <code>true</code> if and only if this factory is available to create
* {@link EFeatureDataStore}s.
*
*/
public boolean isAvailable() {
return EFeatureUtils.isAvailable(eContextInfoMap);
}
/**
* Check if given {@link EFeatureContext} instance is created by this factory.
* <p>
* This method checks for {@link Map#containsValue(Object) value equality}
* between given instance and cached instances.
* </p>
* @param eContext - a {@link EFeatureContext} instance
* @return <code>true</code> if found.
* @see {@link #contains(String)}
*/
public boolean contains(EFeatureContext eContext)
{
return eContextMap.containsValue(eContext);
}
/**
* Check if a {@link EFeatureContext} instance with given ID is created by this factory.
* <p>
* This method checks for {@link Map#containsKey(Object) key equality}
* between given ID and cached IDs.
* </p>
* @param eContextID - {@link EFeature} context {@link EFeatureContext#get id}
* @return <code>true</code> if found.
*/
public boolean contains(String eContextID)
{
return eContextMap.containsKey(eContextID);
}
/**
* Create a {@link EFeatureContext} instance with given ID.
* </p>
* @return a {@link EFeatureContext} instance.
* @throws IllegalArgumentException If an another instance with
* same eContextID already exist.
* {@link EFeatureContext instance}.
*/
public EFeatureContext create(String eContextID) throws IllegalArgumentException
{
return create(eContextID,new EFeatureIDFactoryImpl(), new EFeatureHints());
}
/**
* Create a {@link EFeatureContextInfo} instance from given
* {@link EFeatureContext} instance and cache both instances.
* <p>
* If instance has already joined this factory, this method returns the cached
* {@link EFeatureContextInfo} instance.
* </p>
* @param eContextID
* @param eHints - {@link EFeatureHints} instance
* @return a {@link EFeatureContextInfo} instance.
* @throws IllegalArgumentException If an another instance with
* same eContextID already exist.
* {@link EFeatureContext instance}.
*/
public EFeatureContext create(String eContextID, EFeatureHints eHints) throws IllegalArgumentException
{
return create(eContextID,new EFeatureIDFactoryImpl(),eHints);
}
/**
* Create a {@link EFeatureContextInfo} instance from given
* {@link EFeatureContext} instance and cache both instances.
* <p>
* If instance has already joined this factory, this method returns the cached
* {@link EFeatureContextInfo} instance.
* </p>
* @param eContextID
* @param eIDFactory
* @param eHints - {@link EFeatureHints} instance
* @return a {@link EFeatureContextInfo} instance.
* @throws IllegalArgumentException If an another instance with
* same eContextID already exist.
* {@link EFeatureContext instance}.
*/
public EFeatureContext create(String eContextID, EFeatureIDFactory eIDFactory, EFeatureHints eHints) throws IllegalArgumentException
{
try {
//
// Use default factory?
//
if(eIDFactory==null) eIDFactory = new EFeatureIDFactoryImpl();
//
// Use default hints?
//
if(eHints==null) eHints = new EFeatureHints();
//
// Another instance already registered with given ID?
//
EFeatureContextInfo eContextInfo = eContextInfoMap.get(eContextID);
if(eContextInfo != null)
{
throw new IllegalArgumentException(
"EFeatureContext " + eContextID + "' already exists");
}
//
// All OK, go ahead and create context and structure.
//
EFeatureContext eContext = new EFeatureContextImpl(this, eContextID, eIDFactory);
//
// Map context to id (required by subsequent create methods)
//
eContextMap.put(eContextID, eContext);
//
// Create structure info object
//
eContextInfo = EFeatureContextInfo.create(this,eContextID, eHints);
//
// Map structure to id
//
eContextInfoMap.put(eContextID, eContextInfo);
//
// -----------------------------------------------------
// Add EFeature as prototype.
// -----------------------------------------------------
// This is an important step. It allows the context to
// filter on any EFeature implementation, and enables
// _ANY_ EFeature implementation to be adapted into
// this context.
// -----------------------------------------------------
//
EFeaturePackage ePackage = EFeaturePackage.eINSTANCE;
eContext.eAdd(ePackage);
EFeatureInfo eFeatureInfo = EFeatureInfo.create(eContext, ePackage.getEFeature(), eHints);
//
// -----------------------------------------------------
// Validate structure (required)
// -----------------------------------------------------
// This is an important step. If not done,
// access to methods like getFeatureType() and
// getSRID() will return null or throw exceptions.
// -----------------------------------------------------
//
eFeatureInfo.validate(ePackage, null);
//
// Success!
//
return eContext;
}
catch (IllegalArgumentException e) {
//
// Remove context and structure from cache
//
eContextMap.remove(eContextID);
eContextInfoMap.remove(eContextID);
//
// Log the error
//
LOGGER.throwing(getClass().getName(), "create(EFeatureContext)", e);
//
// Notify again
//
throw e;
}
}
/**
* Dispose given {@link EFeatureContext context}.
* </p>
* @param eContext - the {@link EFeatureContext} instance.
* @throws IllegalArgumentException If given context is not
* created by this factory.
*/
public void dispose(EFeatureContext eContext) {
if(!contains(eContext)) {
throw new IllegalArgumentException("Context "
+ (eContext !=null ? eContext.eContextID() : "null")
+ " is not created by this factory");
}
//
// Get ID
//
String eContextID = eContext.eContextID();
//
// Dispose structure
//
eStructure(eContextID).dispose();
//
// Remove context from cache, allowing garbage collections
//
eContextMap.remove(eContextID);
//
// Tell garbage collector that memory can possible be reclaimed
//
Runtime.getRuntime().gc();
}
/**
* Dispose {@link EFeatureContext context} with given id.
* </p>
* @param eContextID - the {@link EFeatureContext} id.
* @throws IllegalArgumentException If given context is not
* created by this factory.
*/
public void dispose(String eContextID) {
if(!contains(eContextID)) {
throw new IllegalArgumentException("Context "
+ eContextID + " is not created by this factory");
}
dispose(eContextMap.get(eContextID));
}
/**
* Get a EFeature {@link EFeatureContextInfo registry info} instance.
* <p>
* <strong>NOTE</strong>: If no instance was found, a
* {@link IllegalArgumentException} it thrown.
* </p>
* @param eContextID - id of requested {@link EFeatureContextInfo} instance
* @return a {@link EFeatureContextInfo} instance.
* @throws IllegalArgumentException If no {@link EFeatureContext} instance with
* given ID was found.
*/
public EFeatureContextInfo eStructure(String eContextID) throws IllegalArgumentException
{
EFeatureContextInfo eContextInfo = eContextInfoMap.get(eContextID);
if(eContextInfo == null)
{
throw new IllegalArgumentException("EFeatureContext instance with ID "
+ eContextID + " was not found");
}
return eContextInfo;
}
/**
* Get a EFeature {@link EFeatureContext context} instance.
* </p>
* @param eContextID - id of requested {@link EFeatureContext} instance
* @return a {@link EFeatureContextInfo} instance.
* @throws IllegalArgumentException If no {@link EFeatureContext}
* instance was found.
*/
public EFeatureContext eContext(String eContextID)
{
EFeatureContext eContext = eContextMap.get(eContextID);
if(eContext == null)
{
throw new IllegalArgumentException(
"EFeatureContext '" + eContextID + "' does not exist");
}
return eContext;
}
@Override
public Map<Key, ?> getImplementationHints() {
//
// TODO: Add hints for controlling cache size etc.
//
return Collections.emptyMap();
}
}