/*
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*
* 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.core.base.extractors;
import org.drools.core.base.ValueType;
import org.drools.core.base.mvel.MVELCompileable;
import org.drools.core.common.InternalWorkingMemory;
import org.drools.core.definitions.rule.impl.RuleImpl;
import org.drools.core.rule.MVELDialectRuntimeData;
import org.drools.core.util.MVELSafeHelper;
import org.mvel2.MVEL;
import org.mvel2.ParserContext;
import org.mvel2.compiler.ExecutableStatement;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
/**
* A class field extractor that uses MVEL engine to extract the actual value for a given
* expression. We use MVEL to resolve nested accessor expressions.
*/
public class MVELObjectClassFieldReader extends BaseObjectClassFieldReader implements MVELCompileable, MVELClassFieldReader {
private static final long serialVersionUID = 510l;
private ExecutableStatement mvelExpression = null;
private String className;
private String expr;
private boolean typesafe;
private Object evaluationContext;
public MVELObjectClassFieldReader() {
}
public MVELObjectClassFieldReader(String className,
String expr,
boolean typesafe) {
this.className = className;
this.expr = expr;
this.typesafe = typesafe;
setIndex( -1 );
// field (returns) type and value type are set during compile
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
super.readExternal( in );
this.className = ( String ) in.readObject();
this.expr = ( String ) in.readObject();
this.typesafe = in.readBoolean();
this.evaluationContext = in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
super.writeExternal( out );
out.writeObject( this.className );
out.writeObject( this.expr );
out.writeBoolean(this.typesafe);
out.writeObject(this.evaluationContext );
}
public void setExecutableStatement(ExecutableStatement expression) {
this.mvelExpression = expression;
}
public String getClassName() {
return this.className;
}
public boolean isTypeSafe() {
return this.typesafe;
}
public String getExpression() {
return this.expr;
}
public Object getEvaluationContext() {
return evaluationContext;
}
public void setEvaluationContext(Object evaluationContext) {
this.evaluationContext = evaluationContext;
}
public void compile(MVELDialectRuntimeData runtimeData) {
doCompile(this, runtimeData, getEvaluationContext());
}
public void compile(MVELDialectRuntimeData runtimeData, RuleImpl rule) {
doCompile(this, runtimeData, rule.toRuleNameAndPathString());
}
public static void doCompile(MVELClassFieldReader target, MVELDialectRuntimeData runtimeData, Object evaluationContext) {
Class cls;
try {
cls = runtimeData.getRootClassLoader().loadClass( target.getClassName() );
} catch ( ClassNotFoundException e ) {
throw new IllegalStateException( "Unable to compile as Class could not be found '" + target.getClassName() + "'");
}
ParserContext context = new ParserContext(runtimeData.getParserConfiguration(), evaluationContext);
context.addInput( "this", cls );
context.setStrongTyping( target.isTypeSafe() );
MVEL.COMPILER_OPT_ALLOW_NAKED_METH_CALL = true;
MVEL.COMPILER_OPT_ALLOW_OVERRIDE_ALL_PROPHANDLING = true;
MVEL.COMPILER_OPT_ALLOW_RESOLVE_INNERCLASSES_WITH_DOTNOTATION = true;
MVEL.COMPILER_OPT_SUPPORT_JAVA_STYLE_CLASS_LITERALS = true;
ExecutableStatement mvelExpression = (ExecutableStatement)MVEL.compileExpression( target.getExpression(), context);
Class returnType = mvelExpression.getKnownEgressType();
target.setExecutableStatement( mvelExpression );
target.setFieldType( returnType );
target.setValueType( ValueType.determineValueType( returnType ) );
target.setEvaluationContext(evaluationContext);
}
/* (non-Javadoc)
* @see org.kie.base.extractors.BaseObjectClassFieldExtractor#getValue(java.lang.Object)
*/
public Object getValue(InternalWorkingMemory workingMemory,
Object object) {
return MVELSafeHelper.getEvaluator().executeExpression( mvelExpression,
object );
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
final int prime = 31;
int result = super.hashCode();
result = prime * result + ((className == null) ? 0 : className.hashCode());
result = prime * result + ((expr == null) ? 0 : expr.hashCode());
result = prime * result + (typesafe ? 1231 : 1237);
return result;
}
/**
* {@inheritDoc}
*/
@Override
public boolean equals( Object obj ) {
if ( this == obj ) return true;
if ( !super.equals( obj ) ) return false;
if ( getClass() != obj.getClass() ) return false;
MVELObjectClassFieldReader other = (MVELObjectClassFieldReader) obj;
if ( className == null ) {
if ( other.className != null ) return false;
} else if ( !className.equals( other.className ) ) return false;
if ( expr == null ) {
if ( other.expr != null ) return false;
} else if ( !expr.equals( other.expr ) ) return false;
return typesafe == other.typesafe;
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return "[MVELObjectClassFieldReader className=" + className + ", expr=" + expr + ", typesafe=" + typesafe + "]";
}
}