Java Code Examples for org.apache.bcel.generic.ClassGen#getClassName()

public static void main(final String[] argv) throws Exception {
    JavaClass clazz;

    if ((clazz = Repository.lookupClass(argv[0])) == null) {
        clazz = new ClassParser(argv[0]).parse(); // May throw IOException
    }

    final ClassGen cg = new ClassGen(clazz);

    for (final Method method : clazz.getMethods()) {
        final MethodGen mg = new MethodGen(method, cg.getClassName(), cg.getConstantPool());
        cg.replaceMethod(method, mg.getMethod());
    }

    for (final Field field : clazz.getFields()) {
        final FieldGen fg = new FieldGen(field, cg.getConstantPool());
        cg.replaceField(field, fg.getField());
    }

    cg.getJavaClass().dump(clazz.getClassName() + ".clazz");
}
 

/**
 * BCEL-262:
 */
public void testB262() throws ClassNotFoundException
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.PLSETestEnum");
    final ClassGen gen = new ClassGen(clazz);
    final ConstantPoolGen pool = gen.getConstantPool();
    // get the values() method
    final Method m = gen.getMethodAt(0);
    final MethodGen mg = new MethodGen(m, gen.getClassName(), pool);
    final InstructionList il = mg.getInstructionList();
    // get the invokevirtual instruction
    final InstructionHandle ih = il.findHandle(3);
    final InvokeInstruction ii = (InvokeInstruction)(ih.getInstruction());
    // without fix, the getClassName() will throw:
    //   java.lang.IllegalArgumentException: Cannot be used on an array type
    final String cn = ii.getClassName(pool);
    assertEquals("[Lorg.apache.bcel.data.PLSETestEnum;", cn);
}
 

/**
 * BCEL-295:
 */
public void testB295() throws Exception
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.PLSETestClass2");
    final ClassGen cg = new ClassGen(clazz);
    final ConstantPoolGen pool = cg.getConstantPool();
    final Method m = cg.getMethodAt(1);  // 'main'
    final LocalVariableTable lvt = m.getLocalVariableTable();
    final LocalVariable lv = lvt.getLocalVariable(2, 4);  // 'i'
    //System.out.println(lv);
    final MethodGen mg = new MethodGen(m, cg.getClassName(), pool);
    final LocalVariableTable new_lvt = mg.getLocalVariableTable(mg.getConstantPool());
    final LocalVariable new_lv = new_lvt.getLocalVariable(2, 4);  // 'i'
    //System.out.println(new_lv);
    assertEquals("live range length", lv.getLength(), new_lv.getLength());
}
 

/**
 * Create a static method 'getDefault' returning {@link SocketFactory}
 * that creates a new instance of the sub-class and calls its no-argument
 * constructor, the newly created is returned to the caller.
 *
 * @param classGen
 * @param constantPoolGen
 * @param instructionFactory
 */
private static void createGetDefaultStaticMethod(ClassGen classGen,
        ConstantPoolGen constantPoolGen, InstructionFactory instructionFactory)
{
    InstructionList il = new InstructionList();

    String methodName = "getDefault";
    MethodGen mg = new MethodGen(ACC_STATIC | ACC_PUBLIC, // access flags
                        Type.getType(SSLSocketFactory.class),  // return type
                        new Type[0],   // argument types - no args
                        new String[0], // arg names - no args
                        methodName,
                        classGen.getClassName(),    // method, class
                        il,
                        constantPoolGen);

    il.append(instructionFactory.createNew(classGen.getClassName()));
    il.append(InstructionConst.DUP);

    il.append(instructionFactory.createInvoke(classGen.getClassName(), "<init>", Type.VOID,
                                   new Type[] {},
                                   INVOKESPECIAL));

    il.append(InstructionConst.ARETURN);

    mg.setMaxStack();
    classGen.addMethod(mg.getMethod());
    il.dispose();
}
 

byte[] nullAdaptClass(final InputStream is, final String name)
        throws Exception
{
    JavaClass jc = new ClassParser(is, name + ".class").parse();
    ClassGen cg = new ClassGen(jc);
    ConstantPoolGen cp = cg.getConstantPool();
    Method[] ms = cg.getMethods();
    for (int j = 0; j < ms.length; ++j) {
        MethodGen mg = new MethodGen(ms[j], cg.getClassName(), cp);
        boolean lv = ms[j].getLocalVariableTable() == null;
        boolean ln = ms[j].getLineNumberTable() == null;
        if (lv) {
            mg.removeLocalVariables();
        }
        if (ln) {
            mg.removeLineNumbers();
        }
        mg.stripAttributes(skipDebug);
        InstructionList il = mg.getInstructionList();
        if (il != null) {
            InstructionHandle ih = il.getStart();
            while (ih != null) {
                ih = ih.getNext();
            }
            if (compute) {
                mg.setMaxStack();
                mg.setMaxLocals();
            }
        }
        cg.replaceMethod(ms[j], mg.getMethod());
    }
    return cg.getJavaClass().getBytes();
}
 

byte[] nullAdaptClass(final InputStream is, final String name)
        throws Exception
{
    JavaClass jc = new ClassParser(is, name + ".class").parse();
    ClassGen cg = new ClassGen(jc);
    ConstantPoolGen cp = cg.getConstantPool();
    Method[] ms = cg.getMethods();
    for (int j = 0; j < ms.length; ++j) {
        MethodGen mg = new MethodGen(ms[j], cg.getClassName(), cp);
        boolean lv = ms[j].getLocalVariableTable() == null;
        boolean ln = ms[j].getLineNumberTable() == null;
        if (lv) {
            mg.removeLocalVariables();
        }
        if (ln) {
            mg.removeLineNumbers();
        }
        mg.stripAttributes(skipDebug);
        InstructionList il = mg.getInstructionList();
        if (il != null) {
            InstructionHandle ih = il.getStart();
            while (ih != null) {
                ih = ih.getNext();
            }
            if (compute) {
                mg.setMaxStack();
                mg.setMaxLocals();
            }
        }
        cg.replaceMethod(ms[j], mg.getMethod());
    }
    return cg.getJavaClass().getBytes();
}
 

@Benchmark
public void generator(Blackhole bh) throws IOException {
    JarFile jar = getJarFile();

    for (JarEntry entry : getClasses(jar)) {
        byte[] bytes = IOUtils.toByteArray(jar.getInputStream(entry));

        JavaClass clazz = new ClassParser(new ByteArrayInputStream(bytes), entry.getName()).parse();

        ClassGen cg = new ClassGen(clazz);

        for (Method m : cg.getMethods()) {
            MethodGen mg = new MethodGen(m, cg.getClassName(), cg.getConstantPool());
            InstructionList il = mg.getInstructionList();

            if (il != null) {
                mg.getInstructionList().setPositions();
                mg.setMaxLocals();
                mg.setMaxStack();
            }
            cg.replaceMethod(m, mg.getMethod());
        }

        bh.consume(cg.getJavaClass().getBytes());
    }

    jar.close();
}
 

/**
 * BCEL-208: A couple of methods in MethodGen.java need to test for
 * an empty instruction list.
 */
public void testB208() throws ClassNotFoundException
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.PLSETestClass");
    final ClassGen gen = new ClassGen(clazz);
    final ConstantPoolGen pool = gen.getConstantPool();
    final Method m = gen.getMethodAt(1);
    final MethodGen mg = new MethodGen(m, gen.getClassName(), pool);
    mg.setInstructionList(null);
    mg.addLocalVariable("local2", Type.INT, null, null);
    // currently, this will cause null pointer exception
    mg.getLocalVariableTable(pool);
}
 

/**
 * BCEL-79:
 */
public void testB79() throws ClassNotFoundException
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.PLSETestClass");
    final ClassGen gen = new ClassGen(clazz);
    final ConstantPoolGen pool = gen.getConstantPool();
    final Method m = gen.getMethodAt(2);
    final LocalVariableTable lvt = m.getLocalVariableTable();
    //System.out.println(lvt);
    //System.out.println(lvt.getTableLength());
    final MethodGen mg = new MethodGen(m, gen.getClassName(), pool);
    final LocalVariableTable new_lvt = mg.getLocalVariableTable(mg.getConstantPool());
    //System.out.println(new_lvt);
    assertEquals("number of locals", lvt.getTableLength(), new_lvt.getTableLength());
}
 

byte[] counterAdaptClass(final InputStream is, final String name)
        throws Exception
{
    JavaClass jc = new ClassParser(is, name + ".class").parse();
    ClassGen cg = new ClassGen(jc);
    ConstantPoolGen cp = cg.getConstantPool();
    if (!cg.isInterface()) {
        FieldGen fg = new FieldGen(ACC_PUBLIC,
                Type.getType("I"),
                "_counter",
                cp);
        cg.addField(fg.getField());
    }
    Method[] ms = cg.getMethods();
    for (int j = 0; j < ms.length; ++j) {
        MethodGen mg = new MethodGen(ms[j], cg.getClassName(), cp);
        if (!mg.getName().equals("<init>") && !mg.isStatic()
                && !mg.isAbstract() && !mg.isNative())
        {
            if (mg.getInstructionList() != null) {
                InstructionList il = new InstructionList();
                il.append(new ALOAD(0));
                il.append(new ALOAD(0));
                il.append(new GETFIELD(cp.addFieldref(name, "_counter", "I")));
                il.append(new ICONST(1));
                il.append(new IADD());
                il.append(new PUTFIELD(cp.addFieldref(name, "_counter", "I")));
                mg.getInstructionList().insert(il);
                mg.setMaxStack(Math.max(mg.getMaxStack(), 2));
                boolean lv = ms[j].getLocalVariableTable() == null;
                boolean ln = ms[j].getLineNumberTable() == null;
                if (lv) {
                    mg.removeLocalVariables();
                }
                if (ln) {
                    mg.removeLineNumbers();
                }
                cg.replaceMethod(ms[j], mg.getMethod());
            }
        }
    }
    return cg.getJavaClass().getBytes();
}
 

byte[] counterAdaptClass(final InputStream is, final String name)
        throws Exception
{
    JavaClass jc = new ClassParser(is, name + ".class").parse();
    ClassGen cg = new ClassGen(jc);
    ConstantPoolGen cp = cg.getConstantPool();
    if (!cg.isInterface()) {
        FieldGen fg = new FieldGen(ACC_PUBLIC,
                Type.getType("I"),
                "_counter",
                cp);
        cg.addField(fg.getField());
    }
    Method[] ms = cg.getMethods();
    for (int j = 0; j < ms.length; ++j) {
        MethodGen mg = new MethodGen(ms[j], cg.getClassName(), cp);
        if (!mg.getName().equals("<init>") && !mg.isStatic()
                && !mg.isAbstract() && !mg.isNative())
        {
            if (mg.getInstructionList() != null) {
                InstructionList il = new InstructionList();
                il.append(new ALOAD(0));
                il.append(new ALOAD(0));
                il.append(new GETFIELD(cp.addFieldref(name, "_counter", "I")));
                il.append(new ICONST(1));
                il.append(new IADD());
                il.append(new PUTFIELD(cp.addFieldref(name, "_counter", "I")));
                mg.getInstructionList().insert(il);
                mg.setMaxStack(Math.max(mg.getMaxStack(), 2));
                boolean lv = ms[j].getLocalVariableTable() == null;
                boolean ln = ms[j].getLineNumberTable() == null;
                if (lv) {
                    mg.removeLocalVariables();
                }
                if (ln) {
                    mg.removeLineNumbers();
                }
                cg.replaceMethod(ms[j], mg.getMethod());
            }
        }
    }
    return cg.getJavaClass().getBytes();
}
 

private static void test(final File lib) throws IOException {
    final NanoTimer total = new NanoTimer();
    final NanoTimer parseTime = new NanoTimer();
    final NanoTimer cgenTime = new NanoTimer();
    final NanoTimer mgenTime = new NanoTimer();
    final NanoTimer mserTime = new NanoTimer();
    final NanoTimer serTime = new NanoTimer();

    System.out.println("parsing " + lib);

    total.start();
    try (JarFile jar = new JarFile(lib)) {
        final Enumeration<?> en = jar.entries();

        while (en.hasMoreElements()) {
            final JarEntry e = (JarEntry) en.nextElement();
            if (e.getName().endsWith(".class")) {
                byte[] bytes;
                try (InputStream in = jar.getInputStream(e)) {
                    bytes = read(in);
                }

                parseTime.start();
                final JavaClass clazz = new ClassParser(new ByteArrayInputStream(bytes), e.getName()).parse();
                parseTime.stop();

                cgenTime.start();
                final ClassGen cg = new ClassGen(clazz);
                cgenTime.stop();

                final Method[] methods = cg.getMethods();
                for (final Method m : methods) {
                    mgenTime.start();
                    final MethodGen mg = new MethodGen(m, cg.getClassName(), cg.getConstantPool());
                    final InstructionList il = mg.getInstructionList();
                    mgenTime.stop();

                    mserTime.start();
                    if (il != null) {
                        mg.getInstructionList().setPositions();
                        mg.setMaxLocals();
                        mg.setMaxStack();
                    }
                    cg.replaceMethod(m, mg.getMethod());
                    mserTime.stop();
                }

                serTime.start();
                cg.getJavaClass().getBytes();
                serTime.stop();
            }
        }
    }
    total.stop();
    if (REPORT) {
        System.out.println("ClassParser.parse: " + parseTime);
        System.out.println("ClassGen.init: " + cgenTime);
        System.out.println("MethodGen.init: " + mgenTime);
        System.out.println("MethodGen.getMethod: " + mserTime);
        System.out.println("ClassGen.getJavaClass.getBytes: " + serTime);
        System.out.println("Total: " + total);
        System.out.println();
    }
}