package org.drools.compiler.rule.builder.dialect.asm;
import org.drools.core.WorkingMemory;
import org.drools.core.common.InternalFactHandle;
import org.drools.core.rule.Declaration;
import org.drools.compiler.rule.builder.RuleBuildContext;
import org.drools.core.rule.builder.dialect.asm.ClassGenerator;
import org.drools.core.rule.builder.dialect.asm.InvokerDataProvider;
import org.drools.core.rule.builder.dialect.asm.PredicateGenerator;
import org.drools.core.rule.builder.dialect.asm.PredicateStub;
import org.drools.core.spi.CompiledInvoker;
import org.drools.core.spi.PredicateExpression;
import org.drools.core.spi.Tuple;
import org.mvel2.asm.Label;
import org.mvel2.asm.MethodVisitor;
import java.util.Map;
import static org.mvel2.asm.Opcodes.*;
public class ASMPredicateStubBuilder extends AbstractASMPredicateBuilder {
protected byte[] createPredicateBytecode(final RuleBuildContext ruleContext, final Map vars) {
final InvokerDataProvider data = new InvokerContext(vars);
final ClassGenerator generator = InvokerGenerator.createInvokerStubGenerator(data, ruleContext);
createStubPredicate(generator, data, vars);
return generator.generateBytecode();
}
private void createStubPredicate(final ClassGenerator generator, final InvokerDataProvider data, final Map vars) {
generator.setInterfaces(PredicateStub.class, CompiledInvoker.class)
.addField(ACC_PRIVATE + ACC_VOLATILE, "predicate", PredicateExpression.class);
generator.addMethod(ACC_PUBLIC, "createContext", generator.methodDescr(Object.class), new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
mv.visitInsn(ACONST_NULL);
mv.visitInsn(ARETURN);
}
}).addMethod(ACC_PUBLIC, "evaluate", generator.methodDescr(Boolean.TYPE, InternalFactHandle.class, Tuple.class, Declaration[].class, Declaration[].class, WorkingMemory.class, Object.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("predicate", PredicateExpression.class);
mv.visitJumpInsn(IFNONNULL, syncEnd);
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(DUP);
mv.visitVarInsn(ASTORE, 7);
// synchronized(this) {
mv.visitInsn(MONITORENTER);
mv.visitLabel(syncStart);
getFieldFromThis("predicate", PredicateExpression.class);
// if (predicate == null) ...
Label ifNotInitialized = new Label();
mv.visitJumpInsn(IFNONNULL, ifNotInitialized);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 2);
mv.visitVarInsn(ALOAD, 3);
mv.visitVarInsn(ALOAD, 4);
mv.visitVarInsn(ALOAD, 5);
// ... PredicateGenerator.generate(this, tuple, declarations, declarations, workingMemory)
invokeStatic(PredicateGenerator.class, "generate", null, PredicateStub.class, Tuple.class, Declaration[].class, Declaration[].class, WorkingMemory.class);
mv.visitLabel(ifNotInitialized);
mv.visitVarInsn(ALOAD, 7);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l1);
mv.visitJumpInsn(GOTO, syncEnd);
mv.visitLabel(l2);
mv.visitVarInsn(ASTORE, 8);
mv.visitVarInsn(ALOAD, 7);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l3);
mv.visitVarInsn(ALOAD, 8);
mv.visitInsn(ATHROW);
mv.visitLabel(syncEnd);
// } end of synchronized
getFieldFromThis("predicate", PredicateExpression.class);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 2);
mv.visitVarInsn(ALOAD, 3);
mv.visitVarInsn(ALOAD, 4);
mv.visitVarInsn(ALOAD, 5);
mv.visitVarInsn(ALOAD, 6);
invokeInterface(PredicateExpression.class, "evaluate", Boolean.TYPE, InternalFactHandle.class, Tuple.class, Declaration[].class, Declaration[].class, WorkingMemory.class, Object.class);
mv.visitInsn(IRETURN);
}
}).addMethod(ACC_PUBLIC, "setPredicate", generator.methodDescr(null, PredicateExpression.class), new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
putFieldInThisFromRegistry("predicate", PredicateExpression.class, 1);
mv.visitInsn(RETURN);
}
});
}
}