Groovy example source code file (DumpingClassLoader.java)

This example Groovy source code file (DumpingClassLoader.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

asmclassgenerator, asmifierclassvisitor, asmifierclassvisitor, check_class, check_class, classcollector, classgenerator, compileunit, compileunit, debugcollector, debugcollector, dump_class, generatorcontext, io, printwriter

The Groovy DumpingClassLoader.java source code

/*
 * Copyright 2003-2011 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.classgen;

import groovy.lang.GroovyClassLoader;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.CompileUnit;
import org.codehaus.groovy.control.CompilationUnit;
import org.codehaus.groovy.control.CompilerConfiguration;
import org.codehaus.groovy.control.SourceUnit;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.util.ASMifierClassVisitor;
import org.objectweb.asm.util.CheckClassAdapter;

import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StringWriter;

/**
 * A class loader used for debugging the bytecode generation.
 * This will log all bytecode being loaded
 *
 * @author <a href="mailto:james@coredevelopers.net">James Strachan
 * @version $Revision: 21496 $
 */
public class DumpingClassLoader extends GroovyClassLoader implements Opcodes {

    protected static boolean CHECK_CLASS = false;
    protected static boolean DUMP_CLASS = true;

    public DumpingClassLoader(ClassLoader parentLoader) {
        super(parentLoader);
    }


    protected class DebugCollector extends ClassCollector {

        DebugCollector(GroovyClassLoader cl, CompilationUnit unit, SourceUnit su) {
            super(new GroovyClassLoader.InnerLoader(cl), unit, su);
        }

        public void call(ClassVisitor classWriter, ClassNode classNode) {
            // lets test out the class verifier
            if (DUMP_CLASS) {
                dumper.visitClass(classNode);
            }

            if (CHECK_CLASS) {
                checker.visitClass(classNode);
            }

            super.call(classWriter, classNode);
        }
    }

    protected ClassCollector createCollector(CompilationUnit unit) {
        return new DebugCollector(this, unit, null);
    }

    protected ASMifierClassVisitor dumpVisitor = new ASMifierClassVisitor(new PrintWriter(new OutputStreamWriter(System.out)));
    protected ASMifierClassVisitor invisibleDumpVisitor = new ASMifierClassVisitor(new PrintWriter(new StringWriter()));
    protected CompileUnit unit = new CompileUnit(this, new CompilerConfiguration());
    protected ClassGenerator checker =
            new AsmClassGenerator(null,new GeneratorContext(unit), new CheckClassAdapter(invisibleDumpVisitor), null);
    protected ClassGenerator dumper = new AsmClassGenerator(null,new GeneratorContext(unit), dumpVisitor, null);

}