package org.drools.base.mvel;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import org.drools.WorkingMemory;
import org.drools.rule.Declaration;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.Package;
import org.drools.spi.FieldValue;
import org.drools.spi.ReturnValueExpression;
import org.drools.spi.Tuple;
import org.mvel2.MVEL;
public class MVELReturnValueExpression
implements
ReturnValueExpression,
MVELCompileable,
Externalizable {
private static final long serialVersionUID = 400L;
private MVELCompilationUnit unit;
private String id;
private Serializable expr;
private DroolsMVELFactory prototype;
public MVELReturnValueExpression() {
}
public MVELReturnValueExpression(final MVELCompilationUnit unit,
final String id) {
this.unit = unit;
this.id = id;
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
id = in.readUTF();
unit = ( MVELCompilationUnit ) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeUTF( id );
out.writeObject( unit );
}
public void compile(ClassLoader classLoader) {
expr = unit.getCompiledExpression( classLoader );
prototype = unit.getFactory( );
}
public FieldValue evaluate(final Object object,
final Tuple tuple,
final Declaration[] previousDeclarations,
final Declaration[] requiredDeclarations,
final WorkingMemory workingMemory,
final Object ctx ) throws Exception {
DroolsMVELFactory factory = (DroolsMVELFactory) ctx;
factory.setContext( tuple,
null,
object,
workingMemory,
null );
// do we have any functions for this namespace?
Package pkg = workingMemory.getRuleBase().getPackage( "MAIN" );
if ( pkg != null ) {
MVELDialectRuntimeData data = ( MVELDialectRuntimeData ) pkg.getDialectRuntimeRegistry().getDialectData( this.id );
factory.setNextFactory( data.getFunctionFactory() );
}
return org.drools.base.FieldFactory.getFieldValue( MVEL.executeExpression( this.expr,
null,
factory ) );
}
public Object createContext() {
return this.prototype.clone();
}
public String toString() {
return this.unit.getExpression();
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
if ( expr == null ) {
throw new RuntimeException("this MVELReturnValueExpression must be compiled for hashCode");
}
result = prime * result + unit.getExpression().hashCode();
return result;
}
@Override
public boolean equals(Object obj) {
if ( this == obj ) return true;
if ( obj == null ) return false;
if ( getClass() != obj.getClass() ) return false;
if ( expr == null ) {
throw new RuntimeException("this MVELReturnValueExpression must be compiled for equality");
}
MVELReturnValueExpression other = (MVELReturnValueExpression) obj;
if ( other.expr == null ) {
throw new RuntimeException("other MVELReturnValueExpression must be compiled for equality");
}
return this.expr.equals( other.expr );
}
}