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Groovy example source code file (DgmConverter.java)

This example Groovy source code file (DgmConverter.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

acc_final, arraylist, cachedmethod, class, class, classwriter, fileoutputstream, io, label, label, lorg/codehaus/groovy/reflection/cachedclass, methodvisitor, methodvisitor, string, string, util

The Groovy DgmConverter.java source code

/*
 * Copyright 2003-2010 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.tools;

import org.codehaus.groovy.classgen.asm.BytecodeHelper;
import org.codehaus.groovy.reflection.CachedClass;
import org.codehaus.groovy.reflection.CachedMethod;
import org.codehaus.groovy.reflection.ReflectionCache;
import org.codehaus.groovy.reflection.GeneratedMetaMethod;
import org.codehaus.groovy.runtime.DateGroovyMethods;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
import org.codehaus.groovy.runtime.ProcessGroovyMethods;
import org.codehaus.groovy.runtime.SwingGroovyMethods;
import org.codehaus.groovy.runtime.SqlGroovyMethods;
import org.codehaus.groovy.runtime.XmlGroovyMethods;
import org.codehaus.groovy.runtime.EncodingGroovyMethods;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class DgmConverter implements Opcodes{

    public static void main(String[] args) throws IOException, ClassNotFoundException {
        Class [] classes = new Class [] {
            DefaultGroovyMethods.class,
            SwingGroovyMethods.class,
            SqlGroovyMethods.class,
            XmlGroovyMethods.class,
            EncodingGroovyMethods.class,
            DateGroovyMethods.class,
            ProcessGroovyMethods.class
        };

        List<CachedMethod> cachedMethodsList = new ArrayList ();
        for (Class aClass : classes) {
            Collections.addAll(cachedMethodsList, ReflectionCache.getCachedClass(aClass).getMethods());
        }
        final CachedMethod[] cachedMethods = cachedMethodsList.toArray(new CachedMethod[cachedMethodsList.size()]);

        List<GeneratedMetaMethod.DgmMethodRecord> records = new ArrayList ();

        for (int i = 0, cur = 0; i < cachedMethods.length; i++) {
            CachedMethod method = cachedMethods[i];
            if (!method.isStatic() || !method.isPublic())
              continue;

            if (method.getCachedMethod().getAnnotation(Deprecated.class) != null)
                continue;

            if (method.getParameterTypes().length == 0)
              continue;

            final Class returnType = method.getReturnType();

            final String className = "org/codehaus/groovy/runtime/dgm$" + cur;

            GeneratedMetaMethod.DgmMethodRecord record = new GeneratedMetaMethod.DgmMethodRecord ();
            records.add(record);

            record.methodName = method.getName();
            record.returnType = method.getReturnType();
            record.parameters = method.getNativeParameterTypes();
            record.className  = className;

            ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
            cw.visit(V1_3,ACC_PUBLIC, className,null,"org/codehaus/groovy/reflection/GeneratedMetaMethod", null);

            createConstructor(cw);

            final String methodDescriptor = BytecodeHelper.getMethodDescriptor(returnType, method.getNativeParameterTypes());

            createInvokeMethod(method, cw, returnType, methodDescriptor);

            createDoMethodInvokeMethod(method, cw, className, returnType, methodDescriptor);

            createIsValidMethodMethod(method, cw, className);

            cw.visitEnd();

            final byte[] bytes = cw.toByteArray();
            final FileOutputStream fileOutputStream = new FileOutputStream("target/classes/" + className + ".class");
            fileOutputStream.write(bytes);
            fileOutputStream.flush();
            fileOutputStream.close();

            cur++;
        }

        GeneratedMetaMethod.DgmMethodRecord.saveDgmInfo (records, "target/classes/META-INF/dgminfo");
    }

    private static void createConstructor(ClassWriter cw) {
        MethodVisitor mv;
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Ljava/lang/String;Lorg/codehaus/groovy/reflection/CachedClass;Ljava/lang/Class;[Ljava/lang/Class;)V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitVarInsn(ALOAD, 1);
        mv.visitVarInsn(ALOAD, 2);
        mv.visitVarInsn(ALOAD, 3);
        mv.visitVarInsn(ALOAD, 4);
        mv.visitMethodInsn(INVOKESPECIAL, "org/codehaus/groovy/reflection/GeneratedMetaMethod", "<init>", "(Ljava/lang/String;Lorg/codehaus/groovy/reflection/CachedClass;Ljava/lang/Class;[Ljava/lang/Class;)V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }

    private static void createIsValidMethodMethod(CachedMethod method, ClassWriter cw, String className) {
        MethodVisitor mv;
        if (method.getParamsCount() == 2 && method.getParameterTypes()[0].isNumber && method.getParameterTypes()[1].isNumber) {
            // 1 param meta method
            mv = cw.visitMethod(ACC_PUBLIC, "isValidMethod", "([Ljava/lang/Class;)Z", null, null);
            mv.visitCode();
            mv.visitVarInsn(ALOAD, 1);
            Label l0 = new Label();
            mv.visitJumpInsn(IFNULL, l0);
            mv.visitVarInsn(ALOAD, 0);
            mv.visitMethodInsn(INVOKEVIRTUAL, className, "getParameterTypes", "()[Lorg/codehaus/groovy/reflection/CachedClass;");
            mv.visitInsn(ICONST_0);
            mv.visitInsn(AALOAD);
            mv.visitVarInsn(ALOAD, 1);
            mv.visitInsn(ICONST_0);
            mv.visitInsn(AALOAD);
            mv.visitMethodInsn(INVOKEVIRTUAL, "org/codehaus/groovy/reflection/CachedClass", "isAssignableFrom", "(Ljava/lang/Class;)Z");
            Label l1 = new Label();
            mv.visitJumpInsn(IFEQ, l1);
            mv.visitLabel(l0);
            mv.visitInsn(ICONST_1);
            Label l2 = new Label();
            mv.visitJumpInsn(GOTO, l2);
            mv.visitLabel(l1);
            mv.visitInsn(ICONST_0);
            mv.visitLabel(l2);
            mv.visitInsn(IRETURN);
            mv.visitMaxs(0, 0);
            mv.visitEnd();
        }
    }

    private static void createDoMethodInvokeMethod(CachedMethod method, ClassWriter cw, String className, Class returnType, String methodDescriptor) {
        MethodVisitor mv;
        mv = cw.visitMethod(ACC_PUBLIC + ACC_FINAL, "doMethodInvoke", "(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;", null, null);
        mv.visitCode();
        if (method.getParamsCount() == 2 && method.getParameterTypes()[0].isNumber && method.getParameterTypes()[1].isNumber) {
            mv.visitVarInsn(ALOAD,1);
            BytecodeHelper.doCast(mv, method.getParameterTypes()[0].getTheClass());

            mv.visitVarInsn(ALOAD, 0);
            mv.visitMethodInsn(INVOKEVIRTUAL, className, "getParameterTypes", "()[Lorg/codehaus/groovy/reflection/CachedClass;");
            mv.visitInsn(ICONST_0);
            mv.visitInsn(AALOAD);
            mv.visitVarInsn(ALOAD, 2);
            mv.visitInsn(ICONST_0);
            mv.visitInsn(AALOAD);
            mv.visitMethodInsn(INVOKEVIRTUAL, "org/codehaus/groovy/reflection/CachedClass", "coerceArgument", "(Ljava/lang/Object;)Ljava/lang/Object;");

            // cast argument to parameter class, inclusive unboxing
            // for methods with primitive types
            Class type = method.getParameterTypes()[1].getTheClass();
            BytecodeHelper.doCast(mv, type);
        }
        else {
            mv.visitVarInsn(ALOAD, 0);
            mv.visitVarInsn(ALOAD, 2);
            mv.visitMethodInsn(INVOKEVIRTUAL, className, "coerceArgumentsToClasses", "([Ljava/lang/Object;)[Ljava/lang/Object;");
            mv.visitVarInsn(ASTORE, 2);
            mv.visitVarInsn(ALOAD,1);
            BytecodeHelper.doCast(mv, method.getParameterTypes()[0].getTheClass());
            loadParameters(method,2,mv);
        }
        mv.visitMethodInsn(INVOKESTATIC, BytecodeHelper.getClassInternalName(method.getDeclaringClass().getTheClass()), method.getName(), methodDescriptor);
        BytecodeHelper.box(mv, returnType);
        if (method.getReturnType() == void.class) {
            mv.visitInsn(ACONST_NULL);
        }
        mv.visitInsn(ARETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }

    private static void createInvokeMethod(CachedMethod method, ClassWriter cw, Class returnType, String methodDescriptor) {
        MethodVisitor mv;
        mv = cw.visitMethod(ACC_PUBLIC, "invoke", "(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD,1);
        BytecodeHelper.doCast(mv, method.getParameterTypes()[0].getTheClass());
        loadParameters(method,2,mv);
        mv.visitMethodInsn(INVOKESTATIC, BytecodeHelper.getClassInternalName(method.getDeclaringClass().getTheClass()), method.getName(), methodDescriptor);
        BytecodeHelper.box(mv, returnType);
        if (method.getReturnType() == void.class) {
            mv.visitInsn(ACONST_NULL);
        }
        mv.visitInsn(ARETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }

    protected static void loadParameters(CachedMethod method, int argumentIndex, MethodVisitor mv) {
        CachedClass[] parameters = method.getParameterTypes();
        int size = parameters.length-1;
        for (int i = 0; i < size; i++) {
            // unpack argument from Object[]
            mv.visitVarInsn(ALOAD, argumentIndex);
            BytecodeHelper.pushConstant(mv, i);
            mv.visitInsn(AALOAD);

            // cast argument to parameter class, inclusive unboxing
            // for methods with primitive types
            Class type = parameters[i+1].getTheClass();
            BytecodeHelper.doCast(mv, type);
        }
    }
}

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