/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.jena.assembler.assemblers;
import java.util.*;
import org.apache.jena.assembler.* ;
import org.apache.jena.assembler.exceptions.* ;
import org.apache.jena.graph.* ;
import org.apache.jena.rdf.model.* ;
import org.apache.jena.reasoner.* ;
import org.apache.jena.reasoner.rulesys.* ;
/**
The ReasonerFactoryAssembler constructs a ReasonerFactory from the
description. The factory class may be specified by a URL (which looks
the class up in the registry) or by class name; otherwise it defaults to
the GenericRuleReasonerFactory.
<p>
If the class is specified by class name then an instance of that class
is acquired by calling its <code>theInstance</code> method if it
has one. Otherwise a fresh instance is constructed by calling its
zero-argument constructor (and exploding if it hasn't got one).
<p>
Thanks to Adam Cimarosti for provoking this code and providing an
example implementation.
*/
public class ReasonerFactoryAssembler extends AssemblerBase implements Assembler
{
@Override
public Object open( Assembler a, Resource root, Mode irrelevant )
{
checkType( root, JA.ReasonerFactory );
return addSchema( root, a, addRules( root, a, getReasonerFactory( root ) ) );
}
private ReasonerFactory addSchema( Resource root, Assembler a, final ReasonerFactory rf )
{
if (root.hasProperty( JA.ja_schema ))
{
final Graph schema = loadSchema( root, a );
return new ReasonerFactory()
{
@Override
public Reasoner create( Resource configuration )
{
return rf.create( configuration ).bindSchema( schema );
}
@Override
public Model getCapabilities()
{ return rf.getCapabilities(); }
@Override
public String getURI()
{ return rf.getURI(); }
};
}
else
return rf;
}
private Graph loadSchema( Resource root, Assembler a )
{
Graph result = Factory.createDefaultGraph();
for (StmtIterator models = root.listProperties( JA.ja_schema ); models.hasNext();)
loadSchema( result, a, getResource( models.nextStatement() ) );
return result;
}
private void loadSchema( Graph result, Assembler a, Resource root )
{
Model m = a.openModel( root );
GraphUtil.addInto(result, m.getGraph()) ;
}
private ReasonerFactory addRules( Resource root, Assembler a, final ReasonerFactory r )
{
final List<Rule> rules = RuleSetAssembler.addRules( new ArrayList<Rule>(), a, root );
if (rules.size() > 0)
if (r instanceof GenericRuleReasonerFactory)
{
return new ReasonerFactory()
{
@Override
public Reasoner create( Resource configuration )
{
GenericRuleReasoner result = (GenericRuleReasoner) r.create( configuration );
result.addRules( rules );
return result;
}
@Override
public Model getCapabilities()
{ return r.getCapabilities(); }
@Override
public String getURI()
{ return r.getURI(); }
};
}
else
throw new CannotHaveRulesException( root );
return r;
}
protected Reasoner getReasoner( Resource root )
{ return getReasonerFactory( root ).create( root ); }
protected static ReasonerFactory getReasonerFactory( Resource root )
{
Resource reasonerURL = getUniqueResource( root, JA.reasonerURL );
String className = getOptionalClassName( root );
return
className != null ? getReasonerFactoryByClassName( root, className )
: reasonerURL == null ? GenericRuleReasonerFactory.theInstance()
: getReasonerFactoryByURL( root, reasonerURL )
;
}
private static ReasonerFactory getReasonerFactoryByClassName
( Resource root, String className )
{
Class<?> c = loadClass( root, className );
mustBeReasonerFactory( root, c );
ReasonerFactory theInstance = resultFromStatic( c, "theInstance" );
return theInstance == null ? createInstance( root, c ) : theInstance;
}
private static ReasonerFactory createInstance( Resource root, Class<?> c )
{
try
{ return (ReasonerFactory) c.newInstance(); }
catch (Exception e)
{ throw new AssemblerException( root, "could not create instance of " + c.getName(), e ); }
}
private static ReasonerFactory resultFromStatic( Class<?> c, String methodName )
{
try
{ return (ReasonerFactory) c.getMethod( methodName, (Class[])null ).invoke( null, (Object[])null ); }
catch (Exception e)
{ return null; }
}
/**
Throw a <code>NotExpectedTypeException</code> if <code>c</code>
isn't a subclass of <code>ReasonerFactory</code>.
*/
private static void mustBeReasonerFactory( Resource root, Class<?> c )
{
if (!ReasonerFactory.class.isAssignableFrom( c ))
throw new NotExpectedTypeException( root, ReasonerFactory.class, c );
}
/**
Answer the string described by the value of the unique optional
<code>JA.reasonerClass</code> property of <code>root</code>,
or null if there's no such property. The value may be a URI, in which case
it must be a <b>java:</b> URI with content the class name; or it may
be a literal, in which case its lexical form is its class name; otherwise,
BOOM.
*/
private static String getOptionalClassName( Resource root )
{ return getOptionalClassName( root, JA.reasonerClass ); }
/**
Answer a ReasonerFactory which delivers reasoners with the given
URL <code>reasonerURL</code>. If there is no such reasoner, throw
an <code>UnknownreasonerException</code>.
*/
public static ReasonerFactory getReasonerFactoryByURL( Resource root, Resource reasonerURL )
{
String url = reasonerURL.getURI();
ReasonerFactory factory = ReasonerRegistry.theRegistry().getFactory( url );
if (factory == null) throw new UnknownReasonerException( root, reasonerURL );
return factory;
}
}