package org.drools.compiler.rule.builder.dialect.asm;
import org.drools.core.WorkingMemory;
import org.drools.core.rule.GroupElement;
import org.drools.compiler.rule.builder.RuleBuildContext;
import org.drools.core.rule.builder.dialect.asm.ClassGenerator;
import org.drools.core.rule.builder.dialect.asm.ConsequenceGenerator;
import org.drools.core.rule.builder.dialect.asm.ConsequenceStub;
import org.drools.core.rule.builder.dialect.asm.InvokerDataProvider;
import org.drools.core.spi.CompiledInvoker;
import org.drools.core.spi.Consequence;
import org.drools.core.spi.KnowledgeHelper;
import org.mvel2.asm.Label;
import org.mvel2.asm.MethodVisitor;
import java.util.Map;
import static org.mvel2.asm.Opcodes.*;
public class ASMConsequenceStubBuilder extends ASMConsequenceBuilder {
protected byte[] createConsequenceBytecode(final RuleBuildContext ruleContext, final Map<String, Object> consequenceContext) {
// If the LHS contains an OR we cannot use the optimized consequence invoker that traverses the tuple only once
if (isOr(ruleContext.getRule().getLhs())) {
return super.createConsequenceBytecode(ruleContext, consequenceContext);
}
final InvokerDataProvider data = new InvokerContext(consequenceContext);
final ClassGenerator generator = InvokerGenerator.createInvokerStubGenerator(data, ruleContext);
createStubConsequence(generator, data, consequenceContext);
return generator.generateBytecode();
}
private boolean isOr(GroupElement groupElement) {
if (groupElement.isOr()) return true;
for (Object child : groupElement.getChildren()) {
if (child instanceof GroupElement && isOr((GroupElement)child)) return true;
}
return false;
}
private void createStubConsequence(final ClassGenerator generator, final InvokerDataProvider data, final Map<String, Object> vars) {
generator.setInterfaces(ConsequenceStub.class, CompiledInvoker.class)
.addField(ACC_PRIVATE + ACC_VOLATILE, "consequence", Consequence.class);
generator.addMethod(ACC_PUBLIC, "getName", generator.methodDescr(String.class), new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
push((String)vars.get("consequenceName"));
mv.visitInsn(ARETURN); // return the first object on the stack
}
}).addMethod(ACC_PUBLIC, "getNotPatterns", generator.methodDescr(Boolean[].class), new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
returnAsArray((Boolean[]) vars.get("notPatterns"));
}
}).addMethod(ACC_PUBLIC, "evaluate", generator.methodDescr(null, KnowledgeHelper.class, WorkingMemory.class), new String[]{"java/lang/Exception"}, new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
Label syncStart = new Label();
Label syncEnd = new Label();
Label l1 = new Label();
Label l2 = new Label();
mv.visitTryCatchBlock(syncStart, l1, l2, null);
Label l3 = new Label();
mv.visitTryCatchBlock(l2, l3, l2, null);
getFieldFromThis("consequence", Consequence.class);
mv.visitJumpInsn(IFNONNULL, syncEnd);
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(DUP);
mv.visitVarInsn(ASTORE, 3);
// synchronized(this) {
mv.visitInsn(MONITORENTER);
mv.visitLabel(syncStart);
getFieldFromThis("consequence", Consequence.class);
// if (consequence == null) ...
Label ifNotInitialized = new Label();
mv.visitJumpInsn(IFNONNULL, ifNotInitialized);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 2);
// ... ConsequenceGenerator.generate(this, knowledgeHelper, workingMemory)
invokeStatic(ConsequenceGenerator.class, "generate", null, ConsequenceStub.class, KnowledgeHelper.class, WorkingMemory.class);
mv.visitLabel(ifNotInitialized);
mv.visitVarInsn(ALOAD, 3);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l1);
mv.visitJumpInsn(GOTO, syncEnd);
mv.visitLabel(l2);
mv.visitVarInsn(ASTORE, 4);
mv.visitVarInsn(ALOAD, 3);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l3);
mv.visitVarInsn(ALOAD, 4);
mv.visitInsn(ATHROW);
mv.visitLabel(syncEnd);
// } end of synchronized
getFieldFromThis("consequence", Consequence.class);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 2);
invokeInterface(Consequence.class, "evaluate", null, KnowledgeHelper.class, WorkingMemory.class);
mv.visitInsn(RETURN);
}
}).addMethod(ACC_PUBLIC, "setConsequence", generator.methodDescr(null, Consequence.class), new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
putFieldInThisFromRegistry("consequence", Consequence.class, 1);
mv.visitInsn(RETURN);
}
});
}
}