private void createStubEval(
final ClassGenerator generator, final InvokerDataProvider data, final Map vars) {
generator
.setInterfaces(EvalStub.class, CompiledInvoker.class)
.addField(ACC_PRIVATE + ACC_VOLATILE, "eval", EvalExpression.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,
"clone",
generator.methodDescr(EvalExpression.class),
new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(ARETURN);
}
})
.addMethod(
ACC_PUBLIC,
"replaceDeclaration",
generator.methodDescr(null, Declaration.class, Declaration.class))
.addMethod(
ACC_PUBLIC,
"evaluate",
generator.methodDescr(
Boolean.TYPE, Tuple.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("eval", EvalExpression.class);
mv.visitJumpInsn(IFNONNULL, syncEnd);
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(DUP);
mv.visitVarInsn(ASTORE, 5);
// synchronized(this) {
mv.visitInsn(MONITORENTER);
mv.visitLabel(syncStart);
getFieldFromThis("eval", EvalExpression.class);
// if (eval == null) ...
Label ifNotInitialized = new Label();
mv.visitJumpInsn(IFNONNULL, ifNotInitialized);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 2);
mv.visitVarInsn(ALOAD, 3);
// ... EvalGenerator.generate(this, tuple, declarations, workingMemory)
invokeStatic(
EvalGenerator.class,
"generate",
null,
EvalStub.class,
Tuple.class,
Declaration[].class,
WorkingMemory.class);
mv.visitLabel(ifNotInitialized);
mv.visitVarInsn(ALOAD, 5);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l1);
mv.visitJumpInsn(GOTO, syncEnd);
mv.visitLabel(l2);
mv.visitVarInsn(ASTORE, 6);
mv.visitVarInsn(ALOAD, 5);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l3);
mv.visitVarInsn(ALOAD, 6);
mv.visitInsn(ATHROW);
mv.visitLabel(syncEnd);
// } end of synchronized
getFieldFromThis("eval", EvalExpression.class);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 2);
mv.visitVarInsn(ALOAD, 3);
mv.visitVarInsn(ALOAD, 4);
invokeInterface(
EvalExpression.class,
"evaluate",
Boolean.TYPE,
Tuple.class,
Declaration[].class,
WorkingMemory.class,
Object.class);
mv.visitInsn(IRETURN);
}
})
.addMethod(
ACC_PUBLIC,
"setEval",
generator.methodDescr(null, EvalExpression.class),
new ClassGenerator.MethodBody() {
public void body(MethodVisitor mv) {
putFieldInThisFromRegistry("eval", EvalExpression.class, 1);
mv.visitInsn(RETURN);
}
});
}
protected byte[] createEvalBytecode(final RuleBuildContext ruleContext, final Map vars) {
final InvokerDataProvider data = new InvokerContext(vars);
final ClassGenerator generator = InvokerGenerator.createInvokerStubGenerator(data, ruleContext);
createStubEval(generator, data, vars);
return generator.generateBytecode();
}