/**
* Copyright 2010 JBoss Inc
*
* Licensed 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.drools.jsr94.rules.admin;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.Serializable;
import java.net.URL;
import java.util.Map;
import javax.rules.admin.RuleExecutionSet;
import javax.rules.admin.RuleExecutionSetCreateException;
import javax.rules.admin.RuleExecutionSetProvider;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXResult;
import org.drools.compiler.PackageBuilder;
import org.drools.lang.descr.PackageDescr;
import org.drools.rule.Package;
import org.drools.xml.SemanticModules;
import org.drools.compiler.xml.XmlPackageReader;
import org.w3c.dom.Element;
/**
* The Drools implementation of the <code>RuleExecutionSetProvider</code>
* interface which defines <code>RuleExecutionSet</code> creation methods for
* defining <code>RuleExecutionSet</code>s from potentially serializable
* resources.
*
* @see RuleExecutionSetProvider
*
* @author N. Alex Rupp (n_alex <at>codehaus.org)
* @author <a href="mailto:thomas.diesler@softcon-itec.de">thomas diesler </a>
* @author <a href="mailto:michael.frandsen@syngenio.de">michael frandsen </a>
*/
public class RuleExecutionSetProviderImpl
implements
RuleExecutionSetProvider {
/**
* Creates a <code>RuleExecutionSet</code> implementation from an XML
* Document and additional Drools-specific properties. A Drools-specific
* rule execution set is read from the supplied XML Document.
*
* @param ruleExecutionSetElement the XML element that is the source of the
* rule execution set
* @param properties additional properties used to create the
* <code>RuleExecutionSet</code> implementation.
* May be <code>null</code>.
*
* @throws RuleExecutionSetCreateException on rule execution set creation
* error.
*
* @return The created <code>RuleExecutionSet</code>.
*/
public RuleExecutionSet createRuleExecutionSet(final Element ruleExecutionSetElement,
final Map properties) throws RuleExecutionSetCreateException {
try {
// Prepare the DOM source
final Source source = new DOMSource( ruleExecutionSetElement );
final XmlPackageReader xmlPackageReader = new XmlPackageReader( new SemanticModules() );
// Prepare the result
final SAXResult result = new SAXResult( xmlPackageReader.getParser() );
// Create a transformer
final Transformer xformer = TransformerFactory.newInstance().newTransformer();
// Traverse the DOM tree
xformer.transform( source,
result );
final PackageDescr packageDescr = xmlPackageReader.getPackageDescr();
// pre build the package
final PackageBuilder builder = new PackageBuilder();
builder.addPackage( packageDescr );
final Package pkg = builder.getPackage();
final LocalRuleExecutionSetProviderImpl localRuleExecutionSetProvider = new LocalRuleExecutionSetProviderImpl();
return localRuleExecutionSetProvider.createRuleExecutionSet( pkg,
properties );
} catch ( final TransformerException e ) {
throw new RuleExecutionSetCreateException( "could not create RuleExecutionSet: " + e );
}
}
/**
* Creates a <code>RuleExecutionSet</code> implementation from a
* Drools-specific Abstract Syntax Tree (AST) representation and
* Drools-specific properties.
* <p/>
* This method accepts a <code>org.drools.RuleBase</code> object as its
* vendor-specific AST representation.
*
* @param ruleExecutionSetAst the Drools representation of a
* rule execution set
* @param properties additional properties used to create the
* <code>RuleExecutionSet</code> implementation.
* May be <code>null</code>.
*
* @throws RuleExecutionSetCreateException on rule execution set creation
* error.
*
* @return The created <code>RuleExecutionSet</code>.
*/
public RuleExecutionSet createRuleExecutionSet(final Serializable ruleExecutionSetAst,
final Map properties) throws RuleExecutionSetCreateException {
if ( ruleExecutionSetAst instanceof Package ) {
final LocalRuleExecutionSetProviderImpl localRuleExecutionSetProvider = new LocalRuleExecutionSetProviderImpl();
return localRuleExecutionSetProvider.createRuleExecutionSet( ruleExecutionSetAst,
properties );
} else {
throw new IllegalArgumentException( "Serializable object must be " + "an instance of org.drools.rule.RuleSet. It was " + ruleExecutionSetAst.getClass().getName() );
}
}
/**
* Creates a <code>RuleExecutionSet</code> implementation from a URI.
* The URI is opaque to the specification and may be used to refer to the
* file system, a database, or Drools-specific datasource.
*
* @param ruleExecutionSetUri the URI to load the rule execution set from
* @param properties additional properties used to create the
* <code>RuleExecutionSet</code> implementation.
* May be <code>null</code>.
*
* @throws RuleExecutionSetCreateException on rule execution set creation
* error.
* @throws IOException if an I/O error occurs while accessing the URI
*
* @return The created <code>RuleExecutionSet</code>.
*/
public RuleExecutionSet createRuleExecutionSet(final String ruleExecutionSetUri,
final Map properties) throws RuleExecutionSetCreateException,
IOException {
InputStream in = null;
try {
final LocalRuleExecutionSetProviderImpl localRuleExecutionSetProvider = new LocalRuleExecutionSetProviderImpl();
in = new URL( ruleExecutionSetUri ).openStream();
final Reader reader = new InputStreamReader( in );
return localRuleExecutionSetProvider.createRuleExecutionSet( reader,
properties );
} catch ( final IOException ex ) {
throw ex;
} finally {
if ( in != null ) {
in.close();
}
}
}
}