Examples with ClassGen org.apache.bcel.generic.ClassGen used on opensource projects

Example 1 with ClassGen

use of org.apache.bcel.generic.ClassGen in project qpid-broker-j by apache.

the class BrokerTestHelper method createSubClassByteCode.

private static byte[] createSubClassByteCode(final String className, final Class<?>[] interfaces) {
    String[] ifnames = new String[interfaces.length];
    for (int i = 0; i < interfaces.length; i++) {
        ifnames[i] = interfaces[i].getName();
    }
    ClassGen classGen = new ClassGen(className, "java.lang.Object", "<generated>", ACC_PUBLIC | ACC_SUPER | ACC_INTERFACE, ifnames);
    JavaClass javaClass = classGen.getJavaClass();
    try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
        javaClass.dump(out);
        return out.toByteArray();
    } catch (IOException ioex) {
        throw new IllegalStateException("Could not write to a ByteArrayOutputStream - should not happen", ioex);
    }
}

Example 2 with ClassGen

use of org.apache.bcel.generic.ClassGen in project core by s4.

the class OverloadDispatcherGenerator method generate.

public Class<Object> generate() {
    Random rand = new Random(System.currentTimeMillis());
    String dispatcherClassName = "OverloadDispatcher" + (Math.abs(rand.nextInt() % 3256));
    String interfaceName = "io.s4.processor.OverloadDispatcher";
    if (forSlot) {
        interfaceName = "io.s4.processor.OverloadDispatcherSlot";
    }
    ClassGen cg = new ClassGen(dispatcherClassName, "java.lang.Object", dispatcherClassName + ".java", Constants.ACC_PUBLIC | Constants.ACC_SUPER, new String[] { interfaceName });
    ConstantPoolGen cp = cg.getConstantPool();
    InstructionFactory instFactory = new InstructionFactory(cg, cp);
    InstructionList il = new InstructionList();
    // build constructor method for new class
    MethodGen constructor = new MethodGen(Constants.ACC_PUBLIC, Type.VOID, Type.NO_ARGS, new String[] {}, "<init>", dispatcherClassName, il, cp);
    il.append(InstructionFactory.createLoad(Type.OBJECT, 0));
    il.append(instFactory.createInvoke("java.lang.Object", "<init>", Type.VOID, Type.NO_ARGS, Constants.INVOKESPECIAL));
    il.append(InstructionFactory.createReturn(Type.VOID));
    constructor.setMaxStack();
    constructor.setMaxLocals();
    cg.addMethod(constructor.getMethod());
    il.dispose();
    // build dispatch method
    il = new InstructionList();
    Type[] dispatchArgumentTypes = null;
    String[] dispatchArgumentNames = null;
    int postArgumentVariableSlot = 3;
    if (forSlot) {
        dispatchArgumentTypes = new Type[] { ObjectType.OBJECT, ObjectType.OBJECT, ObjectType.LONG, abstractWindowingPEType };
        dispatchArgumentNames = new String[] { "slot", "event", "slotTime", "pe" };
        postArgumentVariableSlot = 6;
    } else {
        dispatchArgumentTypes = new Type[] { ObjectType.OBJECT, ObjectType.OBJECT };
        dispatchArgumentNames = new String[] { "pe", "event" };
    }
    MethodGen method = new MethodGen(Constants.ACC_PUBLIC, Type.VOID, dispatchArgumentTypes, dispatchArgumentNames, "dispatch", dispatcherClassName, il, cp);
    List<InstructionHandle> targetInstructions = new ArrayList<InstructionHandle>();
    List<BranchInstruction> branchInstructions = new ArrayList<BranchInstruction>();
    List<BranchInstruction> gotoInstructions = new ArrayList<BranchInstruction>();
    ObjectType peType = new ObjectType(targetClass.getName());
    il.append(InstructionFactory.createLoad(Type.OBJECT, 1));
    il.append(instFactory.createCheckCast(peType));
    il.append(InstructionFactory.createStore(peType, postArgumentVariableSlot));
    for (int i = 0; i < hierarchies.size(); i++) {
        Hierarchy hierarchy = hierarchies.get(i);
        ObjectType hierarchyTop = new ObjectType(hierarchy.getTop().getName());
        InstructionHandle ih = il.append(InstructionFactory.createLoad(Type.OBJECT, 2));
        if (i > 0) {
            targetInstructions.add(ih);
        }
        il.append(new INSTANCEOF(cp.addClass(hierarchyTop)));
        BranchInstruction bi = InstructionFactory.createBranchInstruction(Constants.IFEQ, null);
        il.append(bi);
        branchInstructions.add(bi);
        il.append(InstructionFactory.createLoad(peType, postArgumentVariableSlot));
        il.append(InstructionFactory.createLoad(hierarchyTop, 2));
        il.append(instFactory.createCheckCast(hierarchyTop));
        if (forSlot) {
            il.append(InstructionFactory.createLoad(ObjectType.LONG, 3));
            il.append(InstructionFactory.createLoad(abstractWindowingPEType, 5));
        }
        Type[] argumentTypes = null;
        if (forSlot) {
            argumentTypes = new Type[] { hierarchyTop, ObjectType.LONG, abstractWindowingPEType };
        } else {
            argumentTypes = new Type[] { hierarchyTop };
        }
        il.append(instFactory.createInvoke(targetClass.getName(), "processEvent", Type.VOID, argumentTypes, Constants.INVOKEVIRTUAL));
        // no branch needed for last check
        if (i < (hierarchies.size() - 1)) {
            bi = InstructionFactory.createBranchInstruction(Constants.GOTO, null);
            il.append(bi);
            gotoInstructions.add(bi);
        }
    }
    InstructionHandle returnInstruction = il.append(InstructionFactory.createReturn(Type.VOID));
    for (int i = 0; i < targetInstructions.size(); i++) {
        branchInstructions.get(i).setTarget(targetInstructions.get(i));
    }
    branchInstructions.get(branchInstructions.size() - 1).setTarget(returnInstruction);
    for (BranchInstruction gotoInstruction : gotoInstructions) {
        gotoInstruction.setTarget(returnInstruction);
    }
    method.setMaxStack();
    method.setMaxLocals();
    cg.addMethod(method.getMethod());
    il.dispose();
    JavaClass jc = cg.getJavaClass();
    OverloadDispatcherClassLoader cl = new OverloadDispatcherClassLoader();
    // debug
    if (classDumpFile != null) {
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(classDumpFile);
            fos.write(jc.getBytes());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fos != null)
                try {
                    fos.close();
                } catch (Exception e) {
                }
        }
    }
    return cl.loadClassFromBytes(dispatcherClassName, jc.getBytes());
}

Example 3 with ClassGen

use of org.apache.bcel.generic.ClassGen in project core by s4.

the class ClonerGenerator method generate.

public Class generate(Class clazz) {
    String className = clazz.getName();
    Random rand = new Random(System.currentTimeMillis());
    String clonerClassname = "Cloner" + (Math.abs(rand.nextInt() % 3256));
    ClassGen cg = new ClassGen(clonerClassname, "java.lang.Object", clonerClassname + ".java", Constants.ACC_PUBLIC | Constants.ACC_SUPER, new String[] { "io.s4.util.Cloner" });
    ConstantPoolGen cp = cg.getConstantPool();
    InstructionFactory instFactory = new InstructionFactory(cg, cp);
    InstructionList il = new InstructionList();
    // build constructor method for new class
    MethodGen constructor = new MethodGen(Constants.ACC_PUBLIC, Type.VOID, Type.NO_ARGS, new String[] {}, "<init>", clonerClassname, il, cp);
    il.append(InstructionFactory.createLoad(Type.OBJECT, 0));
    il.append(instFactory.createInvoke("java.lang.Object", "<init>", Type.VOID, Type.NO_ARGS, Constants.INVOKESPECIAL));
    il.append(InstructionFactory.createReturn(Type.VOID));
    constructor.setMaxStack();
    constructor.setMaxLocals();
    cg.addMethod(constructor.getMethod());
    il.dispose();
    // build clone method
    il = new InstructionList();
    MethodGen method = new MethodGen(Constants.ACC_PUBLIC, Type.OBJECT, new Type[] { Type.OBJECT }, new String[] { "arg0" }, "clone", clonerClassname, il, cp);
    il.append(InstructionConstants.ACONST_NULL);
    il.append(InstructionFactory.createStore(Type.OBJECT, 2));
    il.append(InstructionFactory.createLoad(Type.OBJECT, 1));
    il.append(new INSTANCEOF(cp.addClass(new ObjectType(className))));
    BranchInstruction ifeq_6 = InstructionFactory.createBranchInstruction(Constants.IFEQ, null);
    il.append(ifeq_6);
    il.append(InstructionFactory.createLoad(Type.OBJECT, 1));
    il.append(instFactory.createCheckCast(new ObjectType(className)));
    il.append(InstructionFactory.createStore(Type.OBJECT, 2));
    InstructionHandle ih_14 = il.append(InstructionFactory.createLoad(Type.OBJECT, 2));
    il.append(new INSTANCEOF(cp.addClass(new ObjectType("java.lang.Cloneable"))));
    BranchInstruction ifne_18 = InstructionFactory.createBranchInstruction(Constants.IFNE, null);
    il.append(ifne_18);
    il.append(instFactory.createFieldAccess("java.lang.System", "out", new ObjectType("java.io.PrintStream"), Constants.GETSTATIC));
    il.append(new PUSH(cp, "Not cloneable!"));
    il.append(instFactory.createInvoke("java.io.PrintStream", "println", Type.VOID, new Type[] { Type.STRING }, Constants.INVOKEVIRTUAL));
    il.append(InstructionConstants.ACONST_NULL);
    il.append(InstructionFactory.createReturn(Type.OBJECT));
    InstructionHandle ih_31 = il.append(InstructionFactory.createLoad(Type.OBJECT, 2));
    il.append(instFactory.createInvoke(className, "clone", Type.OBJECT, Type.NO_ARGS, Constants.INVOKEVIRTUAL));
    il.append(InstructionFactory.createReturn(Type.OBJECT));
    ifeq_6.setTarget(ih_14);
    ifne_18.setTarget(ih_31);
    method.setMaxStack();
    method.setMaxLocals();
    cg.addMethod(method.getMethod());
    il.dispose();
    JavaClass jc = cg.getJavaClass();
    ClonerClassLoader cl = new ClonerClassLoader();
    return cl.loadClassFromBytes(clonerClassname, jc.getBytes());
}

Example 4 with ClassGen

use of org.apache.bcel.generic.ClassGen in project jop by jop-devel.

the class AppInfo method tryLoadClass.

private ClassInfo tryLoadClass(String className) throws IOException {
    loadLogger.debug("Loading class " + className);
    InputStream is = classPath.getInputStream(className);
    JavaClass javaClass = new ClassParser(is, className).parse();
    is.close();
    if (javaClass.getMajor() > 50) {
        // instruction (requires patching of BCEL code similar to Classpath and InstructionFinder)
        throw new JavaClassFormatError("Classfiles with versions 51.0 (Java 7) and above are currently not supported!");
    }
    return new ClassInfo(new ClassGen(javaClass));
}

Example 5 with ClassGen

use of org.apache.bcel.generic.ClassGen in project jop by jop-devel.

the class AppInfo method createClassInfo.

private ClassInfo createClassInfo(String className, String superClassName, boolean isInterface) {
    String filename = className.replace(".", File.separator) + ".class";
    int af = Constants.ACC_PUBLIC;
    if (isInterface) {
        af |= Constants.ACC_INTERFACE;
    }
    ClassGen clsGen = new ClassGen(className, superClassName, filename, af, new String[0]);
    return new ClassInfo(clsGen);
}