Groovy example source code file (CallSiteGenerator.java)

This example Groovy source code file (CallSiteGenerator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

cachedclass, cachedmethod, callsiteclassloader, classwriter, classwriter, constructor, label, label, ljava/lang/object, ljava/lang/object, ljava/lang/reflect/constructor, methodvisitor, reflection, string, string

The Groovy CallSiteGenerator.java source code

/*
 * Copyright 2003-2009 the original author or authors.
 *
 * 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.codehaus.groovy.runtime.callsite;

import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.classgen.asm.BytecodeHelper;
import org.codehaus.groovy.reflection.CachedClass;
import org.codehaus.groovy.reflection.CachedMethod;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

import groovy.lang.GroovyRuntimeException;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

public class CallSiteGenerator {

    private static final String GRE = BytecodeHelper.getClassInternalName(ClassHelper.make(GroovyRuntimeException.class));
    
    private CallSiteGenerator () {}
    
    private static MethodVisitor writeMethod(ClassWriter cw, String name, int argumentCount, final String superClass, CachedMethod cachedMethod, String receiverType, String parameterDescription, boolean useArray) {
        MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "call" + name, "(L" + receiverType + ";" + parameterDescription + ")Ljava/lang/Object;", null, null);
        mv.visitCode();
        
        final Label tryStart = new Label();
        mv.visitLabel(tryStart);
        
        // call for checking if method is still valid
        for (int i = 0; i < argumentCount; ++i) mv.visitVarInsn(Opcodes.ALOAD, i);
        mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, superClass, "checkCall", "(Ljava/lang/Object;" + parameterDescription + ")Z");
        Label l0 = new Label();
        mv.visitJumpInsn(Opcodes.IFEQ, l0);
        
        // valid method branch

        Class callClass = cachedMethod.getDeclaringClass().getTheClass();
        boolean useInterface = callClass.isInterface();

        String type = BytecodeHelper.getClassInternalName(callClass.getName());
        String descriptor = BytecodeHelper.getMethodDescriptor(cachedMethod.getReturnType(), cachedMethod.getNativeParameterTypes());
        
        // prepare call
        int invokeMethodCode = Opcodes.INVOKEVIRTUAL;
        if (cachedMethod.isStatic()) {
            invokeMethodCode = Opcodes.INVOKESTATIC;
        } else {
            mv.visitVarInsn(Opcodes.ALOAD, 1);
            BytecodeHelper.doCast(mv, callClass);
            if (useInterface) invokeMethodCode = Opcodes.INVOKEINTERFACE;
        }
        
        Method method = cachedMethod.setAccessible();
        Class<?>[] parameters = method.getParameterTypes();
        int size = parameters.length;
        for (int i = 0; i < size; i++) {
            if (useArray) {
                // unpack argument from Object[]
                mv.visitVarInsn(Opcodes.ALOAD, 2);
                BytecodeHelper.pushConstant(mv, i);
                mv.visitInsn(Opcodes.AALOAD);
            } else {
                mv.visitVarInsn(Opcodes.ALOAD, i+2);
            }

            // cast argument to parameter class, inclusive unboxing
            // for methods with primitive types
            BytecodeHelper.doCast(mv, parameters[i]);
        }        
        
        // make call
        mv.visitMethodInsn(invokeMethodCode, type, cachedMethod.getName(), descriptor);

        // produce result
        BytecodeHelper.box(mv, cachedMethod.getReturnType());
        if (cachedMethod.getReturnType() == void.class) {
            mv.visitInsn(Opcodes.ACONST_NULL);
        }

        // return
        mv.visitInsn(Opcodes.ARETURN);
        
        // fall back after method change
        mv.visitLabel(l0);
        for (int i = 0; i < argumentCount; ++i) mv.visitVarInsn(Opcodes.ALOAD, i);
        if (!useArray) {
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, "org/codehaus/groovy/runtime/ArrayUtil", "createArray", "(" + parameterDescription + ")[Ljava/lang/Object;");
        }
        mv.visitMethodInsn(Opcodes.INVOKESTATIC, "org/codehaus/groovy/runtime/callsite/CallSiteArray", "defaultCall" + name, "(Lorg/codehaus/groovy/runtime/callsite/CallSite;L" + receiverType + ";[Ljava/lang/Object;)Ljava/lang/Object;");
        mv.visitInsn(Opcodes.ARETURN);
        
        // exception unwrapping for stackless exceptions
        final Label tryEnd = new Label();
        mv.visitLabel(tryEnd);
        final Label catchStart = new Label();
        mv.visitLabel(catchStart);
        mv.visitMethodInsn(Opcodes.INVOKESTATIC, "org/codehaus/groovy/runtime/ScriptBytecodeAdapter", "unwrap", "(Lgroovy/lang/GroovyRuntimeException;)Ljava/lang/Throwable;");
        mv.visitInsn(Opcodes.ATHROW);        
        mv.visitTryCatchBlock(tryStart, tryEnd, catchStart, GRE);
        
        mv.visitMaxs(0, 0);
        mv.visitEnd();
        return mv;
    }
    

    public static void genCallWithFixedParams(ClassWriter cw, String name, final String superClass, CachedMethod cachedMethod, String receiverType ) {
        if (cachedMethod.getParamsCount() > 4) return;
        
        StringBuilder pdescb = new StringBuilder();
        final int pc = cachedMethod.getParamsCount();
        for (int i = 0; i != pc; ++i) pdescb.append("Ljava/lang/Object;");
        
        writeMethod(cw,name,pc+2,superClass,cachedMethod,receiverType,pdescb.toString(),false);
    }

    public static void genCallXxxWithArray(ClassWriter cw, final String name, final String superClass, CachedMethod cachedMethod, String receiverType) {
        writeMethod(cw,name,3,superClass,cachedMethod,receiverType,"[Ljava/lang/Object;",true);
    }

    private static void genConstructor(ClassWriter cw, final String superClass, String internalName) {
        MethodVisitor mv;
        mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "(Lorg/codehaus/groovy/runtime/callsite/CallSite;Lgroovy/lang/MetaClassImpl;Lgroovy/lang/MetaMethod;[Ljava/lang/Class;Ljava/lang/reflect/Constructor;)V", null, null);
        mv.visitCode();
        mv.visitVarInsn(Opcodes.ALOAD, 0);
        mv.visitVarInsn(Opcodes.ALOAD, 1);
        mv.visitVarInsn(Opcodes.ALOAD, 2);
        mv.visitVarInsn(Opcodes.ALOAD, 3);
        mv.visitVarInsn(Opcodes.ALOAD, 4);
        mv.visitMethodInsn(Opcodes.INVOKESPECIAL, superClass, "<init>", "(Lorg/codehaus/groovy/runtime/callsite/CallSite;Lgroovy/lang/MetaClassImpl;Lgroovy/lang/MetaMethod;[Ljava/lang/Class;)V");

        mv.visitVarInsn(Opcodes.ALOAD, 5);
        mv.visitFieldInsn(Opcodes.PUTSTATIC, internalName, "__constructor__", "Ljava/lang/reflect/Constructor;");

        mv.visitInsn(Opcodes.RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }

    public static byte[] genPogoMetaMethodSite(CachedMethod cachedMethod, ClassWriter cw, String name) {
        String internalName = name.replace('.', '/');
        cw.visit(Opcodes.V1_4, Opcodes.ACC_PUBLIC | Opcodes.ACC_SYNTHETIC, internalName, null, "org/codehaus/groovy/runtime/callsite/PogoMetaMethodSite", null);
        cw.visitField(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "__constructor__", "Ljava/lang/reflect/Constructor;", null, null);
 
        genConstructor(cw, "org/codehaus/groovy/runtime/callsite/PogoMetaMethodSite", internalName);

        genCallXxxWithArray(cw, "Current", "org/codehaus/groovy/runtime/callsite/PogoMetaMethodSite", cachedMethod, "groovy/lang/GroovyObject");
        genCallXxxWithArray(cw, "", "org/codehaus/groovy/runtime/callsite/PogoMetaMethodSite", cachedMethod, "java/lang/Object");

        genCallWithFixedParams(cw, "Current", "org/codehaus/groovy/runtime/callsite/PogoMetaMethodSite", cachedMethod, "groovy/lang/GroovyObject");
        genCallWithFixedParams(cw, "", "org/codehaus/groovy/runtime/callsite/PogoMetaMethodSite", cachedMethod, "java/lang/Object");


        cw.visitEnd();

        return cw.toByteArray();
    }

    public static byte[] genPojoMetaMethodSite(CachedMethod cachedMethod, ClassWriter cw, String name) {
        String internalName = name.replace('.', '/');
        cw.visit(Opcodes.V1_4, Opcodes.ACC_PUBLIC | Opcodes.ACC_SYNTHETIC, internalName, null, "org/codehaus/groovy/runtime/callsite/PojoMetaMethodSite", null);
        cw.visitField(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "__constructor__", "Ljava/lang/reflect/Constructor;", null, null);

        genConstructor(cw, "org/codehaus/groovy/runtime/callsite/PojoMetaMethodSite", internalName);

        genCallXxxWithArray(cw, "", "org/codehaus/groovy/runtime/callsite/PojoMetaMethodSite", cachedMethod, "java/lang/Object");
        genCallWithFixedParams(cw, "", "org/codehaus/groovy/runtime/callsite/PojoMetaMethodSite", cachedMethod, "java/lang/Object");

        cw.visitEnd();

        return cw.toByteArray();
    }

    public static byte[] genStaticMetaMethodSite(CachedMethod cachedMethod, ClassWriter cw, String name) {
        String internalName = name.replace('.', '/');
        cw.visit(Opcodes.V1_4, Opcodes.ACC_PUBLIC | Opcodes.ACC_SYNTHETIC, internalName, null, "org/codehaus/groovy/runtime/callsite/StaticMetaMethodSite", null);
        cw.visitField(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "__constructor__", "Ljava/lang/reflect/Constructor;", null, null);
 
        genConstructor(cw, "org/codehaus/groovy/runtime/callsite/StaticMetaMethodSite", internalName);

        genCallXxxWithArray(cw, "", "org/codehaus/groovy/runtime/callsite/StaticMetaMethodSite", cachedMethod, "java/lang/Object");
        genCallXxxWithArray(cw, "Static", "org/codehaus/groovy/runtime/callsite/StaticMetaMethodSite", cachedMethod, "java/lang/Class");
        genCallWithFixedParams(cw, "", "org/codehaus/groovy/runtime/callsite/StaticMetaMethodSite", cachedMethod, "java/lang/Object");
        genCallWithFixedParams(cw, "Static", "org/codehaus/groovy/runtime/callsite/StaticMetaMethodSite", cachedMethod, "java/lang/Class");

        cw.visitEnd();

        return cw.toByteArray();
    }

    public static Constructor compilePogoMethod(CachedMethod cachedMethod) {
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);

        final CachedClass declClass = cachedMethod.getDeclaringClass();
        final CallSiteClassLoader callSiteLoader = declClass.getCallSiteLoader();
        final String name = callSiteLoader.createClassName(cachedMethod.setAccessible());

        final byte[] bytes = genPogoMetaMethodSite(cachedMethod, cw, name);
        
        return callSiteLoader.defineClassAndGetConstructor(name, bytes);
    }

    public static Constructor compilePojoMethod(CachedMethod cachedMethod) {
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);

        final CachedClass declClass = cachedMethod.getDeclaringClass();
        final CallSiteClassLoader callSiteLoader = declClass.getCallSiteLoader();
        final String name = callSiteLoader.createClassName(cachedMethod.setAccessible());

        final byte[] bytes = genPojoMetaMethodSite(cachedMethod, cw, name);
        
        return callSiteLoader.defineClassAndGetConstructor(name, bytes);
    }

    public static Constructor compileStaticMethod(CachedMethod cachedMethod) {
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);

        final CachedClass declClass = cachedMethod.getDeclaringClass();
        final CallSiteClassLoader callSiteLoader = declClass.getCallSiteLoader();
        final String name = callSiteLoader.createClassName(cachedMethod.setAccessible());

        final byte[] bytes = genStaticMetaMethodSite(cachedMethod, cw, name);
        
        return callSiteLoader.defineClassAndGetConstructor(name, bytes);
    }

    public static boolean isCompilable (CachedMethod method) {
        return GroovySunClassLoader.sunVM != null || Modifier.isPublic(method.cachedClass.getModifiers()) && method.isPublic() && publicParams(method);
    }

    private static boolean publicParams(CachedMethod method) {
        for (Class nativeParamType : method.getNativeParameterTypes()) {
            if (!Modifier.isPublic(nativeParamType.getModifiers()))
                return false;
        }
        return true;
    }

}