package org.drools.semantics.python;
/*
* $Id: PythonCondition.java,v 1.4 2005/11/10 04:54:43 mproctor Exp $
*
* Copyright 2002 (C) The Werken Company. All Rights Reserved.
*
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain copyright statements and
* notices. Redistributions must also contain a copy of this document.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name "drools" must not be used to endorse or promote products derived
* from this Software without prior written permission of The Werken Company.
* For written permission, please contact bob@werken.com.
*
* 4. Products derived from this Software may not be called "drools" nor may
* "drools" appear in their names without prior written permission of The Werken
* Company. "drools" is a registered trademark of The Werken Company.
*
* 5. Due credit should be given to The Werken Company.
* (http://drools.werken.com/).
*
* THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE WERKEN COMPANY OR ITS CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.drools.rule.Declaration;
import org.drools.rule.Rule;
import org.drools.smf.SemanticComponent;
import org.drools.spi.Condition;
import org.drools.spi.ConditionException;
import org.drools.spi.Tuple;
import org.python.core.PyObject;
import org.python.core.__builtin__;
/**
* Python expression semantics <code>Condition</code>.
*
* @author <a href="mailto:bob@eng.werken.com">bob mcwhirter </a>
*/
public class PythonCondition extends PythonInterp implements Condition, SemanticComponent
{
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
protected final String semanticType = "python";
protected final String name;
/** Required declarations. */
private Declaration[] requiredDeclarations;
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Construct.
*/
public PythonCondition( String text,
Rule rule ) throws Exception
{
super( text,
rule,
"eval" );
this.name = "condition";
PythonExprAnalyzer analyzer = new PythonExprAnalyzer();
this.requiredDeclarations = analyzer.analyze( getNode( ),
rule.getParameterDeclarations( ) );
}
public String getSemanticType()
{
return semanticType;
}
public String getName()
{
return this.name;
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// org.drools.spi.Condition
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/**
* Determine if the supplied <code>Tuple</code> is allowed by this
* condition.
*
* @param tuple The <code>Tuple</code> to test.
*
* @return <code>true</code> if the <code>Tuple</code> passes this
* condition, else <code>false</code>.
*
* @throws ConditionException if an error occurs during filtering.
*/
public boolean isAllowed( Tuple tuple ) throws ConditionException
{
try
{
PyObject result = __builtin__.eval( getCode( ),
setUpDictionary( tuple, declarationIterator( ) ),
getGlobals( ) );
Object answer = result.__tojava__( Object.class );
if ( !( answer instanceof Number ) )
{
throw new NonBooleanExprException( getText( ) );
}
return ( ( Number ) answer ).intValue( ) != 0;
}
catch ( Exception e )
{
throw new ConditionException( e,
getRule( ),
getText( ) );
}
}
/**
* Retrieve the array of <code>Declaration</code> s required by this condition to perform its duties.
*
* @return The array of <code>Declarations</code> expected on incoming <code>Tuples</code>.
*/
public Declaration[] getRequiredTupleMembers()
{
return this.requiredDeclarations;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
public int hashCode()
{
return this.getText( ).hashCode( );
}
public boolean equals( Object object )
{
if ( this == object )
{
return true;
}
if ( object == null || getClass( ) != object.getClass( ) )
{
return false;
}
return this.getText( ).equals( ( ( PythonInterp ) object ).getText( ) );
}
/**
* PythonInterp needs a declaration iterator.
* BlockConsequence uses the Iterator from Set.
* So we emulate Iterator here so PythonInterp can be used for both.
* @return
*/
public Iterator declarationIterator( )
{
return new Iterator()
{
private int index=0;
public void remove()
{
//null;
}
public boolean hasNext()
{
return (index < requiredDeclarations.length);
}
public Object next()
{
if ( !hasNext( ) )
{
throw new NoSuchElementException( );
}
return requiredDeclarations[this.index++];
}
};
}
}