Simboss asked for notes on IRC just now ... here is the "Example" file I
started people working on (just so I could see what was under
discussion). This probably needs to be supplemented with a bit of
javadoc editing help.
The first file (DefaultFactory) was started as the "one finder to rule
them all)
Tthe second file (ShapefileDataStore) is a worked example of the
approach used, please review the constructors)
Cheers,
Jody
package org.geotools;
import java.net.URL;
import org.geotools.factory.AbstractFactory;
import org.geotools.factory.Factory;
import org.geotools.factory.Hints;
public class ShapefileDataStore {
public static Hints.Key FEATURE_TYPE_FACTORY = new
Hints.Key(FeatureTypeFactory.class);
private URL url;
private Object featureTypeFactory;
public ShapefileDataStore(URL url) {
this(url, new ShapeFeatureTypeFactory());
}
public ShapefileDataStore(URL url, Hints hints) {
this( url, FactoryFinder.factory( FEATURE_TYPE_FACTORY, hints,
ShapeFeatureTypeFactory.class ) );
}
public ShapefileDataStore(URL url, FeatureTypeFactory factory) {
this.url = url;
featureTypeFactory = factory;
}
public void setFeatureTypeFactory( FeatureTypeFactory factory ){
featureTypeFactory = factory;//DefaultFactory.ensure( factory,
FeatureTypeFactory.class );
}
public void run( ) {
FeautreTypeFactory factory = featureTypeFactory;
if ( factory == null ) {
factory = new ShapeFeatureTypeFactory();
}
}
public static void main(String args[]){
FactoryFinder.setOrdering( PojoFeatureTypeFactory.class,
FeatureTypeFactory.class );
}
}
class PojoFeatureTypeFactory extends FeatureTypeFactory {
}
class ShapeFeatureTypeFactory extends FeatureTypeFactory {
public ShapeFeatureTypeFactory(){}
}
class FeatureTypeFactory {
}
class FactoryFinder {
public static FeatureTypeFactory factory(Hints.Key key, Hints hints, Class
myDefault ){
if( hints.containsKey( key )){
return getFactory( key.getValueClass(), hints );
}
if (factory.getClass().getName().startsWith("org.geotools")){
return new ShapeFeatureTypeFactory();
}
if( true ){ // do we have a user supplied "global" setting - say
PojoFeatureTypeFactory
return factory;
}
}
public static FeatureTypeFactory getFactory(Class class1, Hints hints) {
return null;
}
}
main( ) {
FactoryFinder.addFactoryRegister( new ServiceIterator );
}
/*
* GeoTools - OpenSource mapping toolkit
* http://geotools.org
* (C) 2006-2006, GeoTools Project Managment Committee (PMC)
*
* 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;
import org.geotools.factory.Factory;
/**
* Ease of use class for for Factory handling.
* <p>
* This class is intended for:
* <ul>
* <li><b>geotools users:</b> please use this class to find a "default" factory
* implementation.</li>
* <li><b>geotools implementators:</b> please use this class to ensure you have
an
* appropriate factory implementation.</li>
* </ul>
* Examples:<pre><code>
* </code></pre>
*
* @author Jody Garnett, Refractions Research Inc.
*/
public class DefaultFactory {
/**
* User helper method to locate a shared "default" factory.
* <p>
* The default factory's are set once for your entire application.
* <p>
* You can set defaults directly for the entrie factory:<pre><code>
* DefaultFactory.
* </pre></code>
*
* default( FactoryType type, class Type ) method.
* Or you can make use of Pico or Spring contains as illustrated in the
ext/pico and ext/spring.
* </p>
* @param factoryType
* @return
*/
public static Factory lookup( Class factoryType ){
return null;
}
/**
* Implementor helper method for constructor injection.
* <p>
* Example of BestPractice:<pre><code>
*
* public ShapefileDataStore( URL url ){
* this( url, new ShapeFeatureTypeFactory() );
* }
*
* public ShapefileDataStore( URL url, Hints hints){
* FeatureTypeFactory factory = FactoryFinder.getFactory(
FeatureTypeFactory.class, hints);
* if (!(factory instanceof ShapeFeatureTypeFactory)) {
* // CASE 1:
* factory = new ShapeFeatureTypeFactory();
*
* // CASE 2:
* hints.put(FEATURE_TYPE_FACTORY, ShapeFeatureTypeFactory.class);
* factory = FactoryFinder.getFactory( FeatureTypeFactory.class,
hints);
* }
* this( url, FactoryFinder.getFactory( FeatureTypeFactory.class,
hints, ShapeFeatureTypeFactory.class) );
*
* // -1 default feature factory type
* // 0 shapefile feature factory type
* // 1 pojo feature factory
* }
* public ShapefileDataStore( URL url, FeatureTypeFactory factory){
* this.url = url;
* featureTypeFactory = DefaultFactory.confirm( factory,
FeatureTypeFactory.class );
* }
* </code></pre>
* @param factory
* @param factoryType
* @return
*/
public static Factory comfirm( Factory factory, Class factoryType ){
if( factory != null ) {
return factory;
}
if( factoryType.isInstance( factory )){
throw new ClassCastException("Requred a "+factoryType );
}
return find( factoryType );
}
/**
* Implementor helper method for setter injection.
* <p>
* Example of BestPractice:<pre><code>
* public void setFeatureTypeFactory( factory ){
* featureTypeFactory = DefaultFactory.ensure( factory,
FeatureTypeFactory.class );
* }
* </code></pre>
*
* @param factory
* @param factoryType
* @return
*/
public static Factory ensure( Object factory, Class factoryType ){
if( factory == null ) {
throw new NullPointerException("Requred a "+factoryType );
}
if( factoryType.isInstance( factory )){
throw new ClassCastException("Requred a "+factoryType );
}
return factory;
}
/**
* Register this provided factory as a "default" for the entire library.
* <p>
* Please use this method to set a "default" as shown below:<pre><code>
* public static void main( String args[] ){
* DefaultFactory.register( new PojoFeatureFactory() );
* }
* </pre></code>
*
* Please note that your "default" will only be used as needed, many things
like ShapefileDataStore
* will make use of their own defaults that are "optimized" for efficiency.
To take control in these
* situtations please do the following:<pre></code>
* ShapefileDataStore shape = new ShapefileDataStore( url );
* shape.setFeatureFactory( new PojoFeatureFactory() );
* </code></pre>
*
* @param factory
*/
public static void register( Factory factory ){
}
public static void register( Class factoryType ){
}
public static void synchornize( ContainerAdapter container ){
}
/**
* This interface
*
*/
public static interface ContainerAdapter {
}
}-------------------------------------------------------------------------
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