Java Class Viewer

/*
 * Main.java    Created on Apr 27, 2009
 *
 * Copyright 2009, FreeInternals.org. All rights reserved.
 * Use is subject to license terms.
 */
package org.freeinternals.demo;

import java.io.File;
import java.io.IOException;
import java.util.Enumeration;
import java.util.jar.JarFile;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import org.freeinternals.classfile.core.AbstractCPInfo;
import org.freeinternals.classfile.core.AccessFlags;
import org.freeinternals.classfile.core.AttributeCount;
import org.freeinternals.classfile.core.AttributeInfo;
import org.freeinternals.classfile.core.CPCount;
import org.freeinternals.classfile.core.ClassFile;
import org.freeinternals.classfile.core.ClassFormatException;
import org.freeinternals.classfile.core.FieldCount;
import org.freeinternals.classfile.core.FieldInfo;
import org.freeinternals.classfile.core.Interface;
import org.freeinternals.classfile.core.InterfaceCount;
import org.freeinternals.classfile.core.MajorVersion;
import org.freeinternals.classfile.core.MethodCount;
import org.freeinternals.classfile.core.MethodInfo;
import org.freeinternals.classfile.core.MinorVersion;
import org.freeinternals.classfile.core.SuperClass;
import org.freeinternals.classfile.core.ThisClass;
import org.freeinternals.classfile.ui.Tool;

/**
 *
 * @author Amos Shi
 */
public class jCFL_CodeDemo {

    /**
     * Before running this application, please ensure the .class file and .jar
     * file exist in the specified location.
     *
     * @param args command line arguments
     */
    public static void main(final String[] args) {
        try {
            jCFL_CodeDemo.extractClassFile();
            jCFL_CodeDemo.extractJarFile();
        } catch (IOException ex) {
            Logger.getLogger(jCFL_CodeDemo.class.getName()).log(Level.SEVERE, null, ex);
            System.out.println(ex.toString());
        } catch (ClassFormatException ex) {
            Logger.getLogger(jCFL_CodeDemo.class.getName()).log(Level.SEVERE, null, ex);
            System.out.println(ex.toString());
        }
    }

    private static void extractClassFile() throws IOException, ClassFormatException {

        File file = new File("C:/Temp/File.class");
        byte[] classByteArray = Tool.readClassFile(file);
        ClassFile classfile = new ClassFile(classByteArray);

        jCFL_CodeDemo.printClassFile(classfile);
    }

    private static void extractJarFile() throws IOException, ClassFormatException {
        File file = new File("C:/Temp/tools.jar");
        JarFile jarFile = new JarFile(file, false, JarFile.OPEN_READ);
        ZipFile zipFile = jarFile;

        final Enumeration zipEntries = zipFile.entries();
        while (zipEntries.hasMoreElements()) {
            ZipEntry zipEntry = (ZipEntry) zipEntries.nextElement();
            if (!zipEntry.getName().endsWith(".class")) {
                continue;
            }

            byte[] classByteArray = Tool.readClassFile(zipFile, zipEntry);
            ClassFile classfile = new ClassFile(classByteArray);

            System.out.println();
            System.out.println(zipEntry.getName());
            jCFL_CodeDemo.printClassFile(classfile);
        }
    }

    private static void printClassFile(ClassFile classfile) {
        // Minor & Major version
        MinorVersion minorVersion = classfile.getMinorVersion();
        System.out.println("Class File Minor Version: " + minorVersion.getValue());

        MajorVersion majorVersion = classfile.getMajorVersion();
        System.out.println("Class File Major Version: " + majorVersion.getValue());

        // Constant Pool
        CPCount cpCount = classfile.getCPCount();
        System.out.println("Constant Pool size: " + cpCount.getValue());

        AbstractCPInfo[] cpArray = classfile.getConstantPool();
        for (int i = 1; i < cpCount.getValue(); i++) {
            System.out.println(
                    String.format("Constant Pool [%d]: %s", i, classfile.getCPDescription(i)));
            short tag = cpArray[i].getTag();
            if ((tag == AbstractCPInfo.CONSTANT_Double) || (tag == AbstractCPInfo.CONSTANT_Long)) {
                i++;
            }
        }

        // Access flag, this & super class
        AccessFlags accessFlags = classfile.getAccessFlags();
        System.out.println("Class Modifier: " + accessFlags.getModifiers());

        ThisClass thisClass = classfile.getThisClass();
        System.out.println("This Class Name Index: " + thisClass.getValue());
        System.out.println("This Class Name: " + classfile.getCPDescription(thisClass.getValue()));

        SuperClass superClass = classfile.getSuperClass();
        System.out.println("Super Class Name Index: " + superClass.getValue());
        if (superClass.getValue() == 0) {
            System.out.println("Super Class Name: java.lang.Object");
        } else {
            System.out.println("Super Class Name: " + classfile.getCPDescription(superClass.getValue()));
        }

        // Interfaces
        InterfaceCount interfactCount = classfile.getInterfacesCount();
        System.out.println("Interface Count: " + interfactCount.getValue());

        if (interfactCount.getValue() > 0) {
            Interface[] interfaceArray = classfile.getInterfaces();
            for (int i = 0; i < interfaceArray.length; i++) {
                System.out.println(
                        String.format("Interface [%d] Name Index: %d", i, interfaceArray[i].getValue()));
                System.out.println(
                        String.format("Interface [%d] Name: %s", i, classfile.getCPDescription(interfaceArray[i].getValue())));
            }
        }

        // Fields
        FieldCount fieldCount = classfile.getFieldCount();
        System.out.println("Field count: " + fieldCount.getValue());

        if (fieldCount.getValue() > 0) {
            FieldInfo[] fieldArray = classfile.getFields();
            for (int i = 0; i < fieldArray.length; i++) {
                System.out.println(String.format("Field [%d]: %s", i, fieldArray[i].getDeclaration()));
            }
        }

        // Methods
        MethodCount methodCount = classfile.getMethodCount();
        System.out.println("Method count: " + methodCount.getValue());

        if (methodCount.getValue() > 0) {
            MethodInfo[] methodArray = classfile.getMethods();
            for (int i = 0; i < methodArray.length; i++) {
                System.out.println(String.format("Method [%d]: %s", i, methodArray[i].getDeclaration()));
            }
        }

        // Attributes
        AttributeCount attributeCount = classfile.getAttributeCount();
        System.out.println("Attribute count: " + attributeCount.getValue());

        AttributeInfo[] attributeArray = classfile.getAttributes();
        for (int i = 0; i < attributeArray.length; i++) {
            System.out.println(String.format("Attribute [%d]: %s", i, attributeArray[i].getName()));
        }

    }
}