org.apache.bcel.classfile.ConstantPool Java Examples

/**
 * Main class, to find strings in class files.
 * @param args Arguments to program.
 */
public static void main(String[] args) {
    try {
        JavaClass clazz = Repository.lookupClass(args[0]);
        ConstantPool cp = clazz.getConstantPool();
        Constant[] consts = cp.getConstantPool();


        for (int i = 0; i < consts.length; i++) {

            if (consts[i] instanceof ConstantString) {
                System.out.println("Found String: " +
                        ((ConstantString)consts[i]).getBytes(cp));
            }
        }
    }
    catch (Exception e) {
        e.printStackTrace();
    }
}
 

/**
 * @return mnemonic for instruction with symbolic references resolved
 */
@Override
public String toString( final ConstantPool cp ) {
    final Constant c = cp.getConstant(super.getIndex());
    final StringTokenizer tok = new StringTokenizer(cp.constantToString(c));

    final String opcodeName = Const.getOpcodeName(super.getOpcode());

    final StringBuilder sb = new StringBuilder(opcodeName);
    if (tok.hasMoreTokens()) {
        sb.append(" ");
        sb.append(tok.nextToken().replace('.', '/'));
        if (tok.hasMoreTokens()) {
            sb.append(tok.nextToken());
        }
    }

    return sb.toString();
}
 

@Override
public void visit(ConstantPool pool) {
    for (Constant constant : pool.getConstantPool()) {
        if (constant instanceof ConstantClass) {
            ConstantClass cc = (ConstantClass) constant;
            @SlashedClassName
            String className = cc.getBytes(pool);
            if ("java/util/Calendar".equals(className) || "java/text/DateFormat".equals(className)) {
                sawDateClass = true;
                break;
            }
            if (className.charAt(0) != '[') {
                try {
                    ClassDescriptor cDesc = DescriptorFactory.createClassDescriptor(className);

                    if (subtypes2.isSubtype(cDesc, calendarType) || subtypes2.isSubtype(cDesc, dateFormatType)) {
                        sawDateClass = true;
                        break;
                    }
                } catch (ClassNotFoundException e) {
                    reporter.reportMissingClass(e);
                }
            }
        }
    }
}
 

/**
 * Returns true if given constant pool probably has a reference to any of supplied methods
 * Useful to exclude from analysis uninteresting classes
 * @param cp constant pool
 * @param methods methods collection
 * @return true if method is found
 */
public static boolean hasInterestingMethod(ConstantPool cp, Collection<MethodDescriptor> methods) {
    for (Constant c : cp.getConstantPool()) {
        if (c instanceof ConstantMethodref || c instanceof ConstantInterfaceMethodref) {
            ConstantCP desc = (ConstantCP) c;
            ConstantNameAndType nameAndType = (ConstantNameAndType) cp.getConstant(desc.getNameAndTypeIndex());
            String className = cp.getConstantString(desc.getClassIndex(), Const.CONSTANT_Class);
            String name = ((ConstantUtf8) cp.getConstant(nameAndType.getNameIndex())).getBytes();
            String signature = ((ConstantUtf8) cp.getConstant(nameAndType.getSignatureIndex())).getBytes();
            // We don't know whether method is static thus cannot use equals
            int hash = FieldOrMethodDescriptor.getNameSigHashCode(name, signature);
            for (MethodDescriptor method : methods) {
                if (method.getNameSigHashCode() == hash
                        && (method.getSlashedClassName().isEmpty() || method.getSlashedClassName().equals(className))
                        && method.getName().equals(name) && method.getSignature().equals(signature)) {
                    return true;
                }
            }
        }
    }
    return false;
}
 

public static String[] getClassDependencies(final ConstantPool pool) {
    final String[] tempArray = new String[pool.getLength()];
    int size = 0;
    final StringBuilder buf = new StringBuilder();

    for (int idx = 0; idx < pool.getLength(); idx++) {
        final Constant c = pool.getConstant(idx);
        if (c != null && c.getTag() == Constants.CONSTANT_Class) {
            final ConstantUtf8 c1 = (ConstantUtf8) pool.getConstant(((ConstantClass) c).getNameIndex());
            buf.setLength(0);
            buf.append(c1.getBytes());
            for (int n = 0; n < buf.length(); n++) {
                if (buf.charAt(n) == '/') {
                    buf.setCharAt(n, '.');
                }
            }

            tempArray[size++] = buf.toString();
        }
    }

    final String[] dependencies = new String[size];
    System.arraycopy(tempArray, 0, dependencies, 0, size);
    return dependencies;
}
 

public boolean isCaught(ClassContext classContext, Method method, UnconditionalValueDerefSet entryFact, ValueNumber paramVN) {
    boolean caught = true;

    Set<Location> dereferenceSites = entryFact.getDerefLocationSet(paramVN);
    if (dereferenceSites != null && !dereferenceSites.isEmpty()) {
        ConstantPool cp = classContext.getJavaClass().getConstantPool();

        for (Location loc : dereferenceSites) {
            if (!FindNullDeref.catchesNull(cp, method.getCode(), loc)) {
                caught = false;
            }
        }

    }
    return caught;
}
 

/**
 * Main class, to find strings in class files.
 * @param args Arguments to program.
 */
public static void main(String[] args) {
    try {
        JavaClass clazz = Repository.lookupClass(args[0]);
        ConstantPool cp = clazz.getConstantPool();
        Constant[] consts = cp.getConstantPool();


        for (int i = 0; i < consts.length; i++) {

            if (consts[i] instanceof ConstantString) {
                System.out.println("Found String: " +
                        ((ConstantString)consts[i]).getBytes(cp));
            }
        }
    }
    catch (Exception e) {
        e.printStackTrace();
    }
}
 

public static void main(final String[] argv) throws Exception {
    for (final String arg : argv) {
        if (arg.endsWith(".class")) {
            final JavaClass java_class = new ClassParser(arg).parse();
            final ConstantPool constants = java_class.getConstantPool();
            final String file_name = arg.substring(0, arg.length() - 6) + "_hello.class";
            cp = new ConstantPoolGen(constants);

            helloifyClassName(java_class);

            out = cp.addFieldref("java.lang.System", "out", "Ljava/io/PrintStream;");
            println = cp.addMethodref("java.io.PrintStream", "println", "(Ljava/lang/String;)V");
            // Patch all methods.
            final Method[] methods = java_class.getMethods();

            for (int j = 0; j < methods.length; j++) {
                methods[j] = helloifyMethod(methods[j]);
            }

            // Finally dump it back to a file.
            java_class.setConstantPool(cp.getFinalConstantPool());
            java_class.dump(file_name);
        }
    }
}
 

/**
 * @return the (finally) built up Java class object.
 */
public JavaClass getJavaClass() {
    final int[] interfaces = getInterfaces();
    final Field[] fields = getFields();
    final Method[] methods = getMethods();
    Attribute[] attributes = null;
    if (annotationList.isEmpty()) {
        attributes = getAttributes();
    } else {
        // TODO: Sometime later, trash any attributes called 'RuntimeVisibleAnnotations' or 'RuntimeInvisibleAnnotations'
        final Attribute[] annAttributes  = AnnotationEntryGen.getAnnotationAttributes(cp, getAnnotationEntries());
        attributes = new Attribute[attributeList.size()+annAttributes.length];
        attributeList.toArray(attributes);
        System.arraycopy(annAttributes,0,attributes,attributeList.size(),annAttributes.length);
    }
    // Must be last since the above calls may still add something to it
    final ConstantPool _cp = this.cp.getFinalConstantPool();
    return new JavaClass(classNameIndex, superclass_name_index, fileName, major, minor,
            super.getAccessFlags(), _cp, interfaces, fields, methods, attributes);
}
 

/**
 * Returns the indices of all class symbol references to {@code targetClassName} in the constant
 * pool of {@code sourceJavaClass}.
 */
ImmutableSet<Integer> constantPoolIndexForClass(
    JavaClass sourceJavaClass, String targetClassName) {
  ImmutableSet.Builder<Integer> constantPoolIndicesForTarget = ImmutableSet.builder();

  ConstantPool sourceConstantPool = sourceJavaClass.getConstantPool();
  Constant[] constantPool = sourceConstantPool.getConstantPool();
  // constantPool indexes start from 1. 0th entry is null.
  for (int poolIndex = 1; poolIndex < constantPool.length; poolIndex++) {
    Constant constant = constantPool[poolIndex];
    if (constant != null) {
      byte constantTag = constant.getTag();
      if (constantTag == Const.CONSTANT_Class) {
        ConstantClass constantClass = (ConstantClass) constant;
        ClassSymbol classSymbol = makeSymbol(constantClass, sourceConstantPool, sourceJavaClass);
        if (targetClassName.equals(classSymbol.getClassBinaryName())) {
          constantPoolIndicesForTarget.add(poolIndex);
        }
      }
    }
  }

  return constantPoolIndicesForTarget.build();
}
 

/**
 * Override this method to create you own classes on the fly. The
 * name contains the special token $$BCEL$$. Everything before that
 * token is considered to be a package name. You can encode your own
 * arguments into the subsequent string. You must ensure however not
 * to use any "illegal" characters, i.e., characters that may not
 * appear in a Java class name too
 * <p>
 * The default implementation interprets the string as a encoded compressed
 * Java class, unpacks and decodes it with the Utility.decode() method, and
 * parses the resulting byte array and returns the resulting JavaClass object.
 * </p>
 *
 * @param class_name compressed byte code with "$$BCEL$$" in it
 */
protected JavaClass createClass( final String class_name ) {
    final int index = class_name.indexOf(BCEL_TOKEN);
    final String real_name = class_name.substring(index + BCEL_TOKEN.length());
    JavaClass clazz = null;
    try {
        final byte[] bytes = Utility.decode(real_name, true);
        final ClassParser parser = new ClassParser(new ByteArrayInputStream(bytes), "foo");
        clazz = parser.parse();
    } catch (final IOException e) {
        e.printStackTrace();
        return null;
    }
    // Adapt the class name to the passed value
    final ConstantPool cp = clazz.getConstantPool();
    final ConstantClass cl = (ConstantClass) cp.getConstant(clazz.getClassNameIndex(),
            Const.CONSTANT_Class);
    final ConstantUtf8 name = (ConstantUtf8) cp.getConstant(cl.getNameIndex(),
            Const.CONSTANT_Utf8);
    name.setBytes(class_name.replace('.', '/'));
    return clazz;
}
 

ConstantHTML(final String dir, final String class_name, final String class_package, final Method[] methods,
        final ConstantPool constant_pool) throws IOException {
    this.className = class_name;
    this.classPackage = class_package;
    this.constantPool = constant_pool;
    this.methods = methods;
    constants = constant_pool.getConstantPool();
    file = new PrintWriter(new FileOutputStream(dir + class_name + "_cp.html"));
    constantRef = new String[constants.length];
    constantRef[0] = "<unknown>";
    file.println("<HTML><BODY BGCOLOR=\"#C0C0C0\"><TABLE BORDER=0>");
    // Loop through constants, constants[0] is reserved
    for (int i = 1; i < constants.length; i++) {
        if (i % 2 == 0) {
            file.print("<TR BGCOLOR=\"#C0C0C0\"><TD>");
        } else {
            file.print("<TR BGCOLOR=\"#A0A0A0\"><TD>");
        }
        if (constants[i] != null) {
            writeConstant(i);
        }
        file.print("</TD></TR>\n");
    }
    file.println("</TABLE></BODY></HTML>");
    file.close();
}
 

/**
 * Called to indicate that a field load or store was encountered.
 *
 * @param cpIndex
 *            the constant pool index of the fieldref
 * @param isStatic
 *            true if it is a static field access
 * @param isLoad
 *            true if the access is a load
 */
private void setField(int cpIndex, boolean isStatic, boolean isLoad) {
    // We only allow one field access for an accessor method.
    accessCount++;
    if (accessCount != 1) {
        access = null;
        return;
    }

    ConstantPool cp = javaClass.getConstantPool();
    ConstantFieldref fieldref = (ConstantFieldref) cp.getConstant(cpIndex);

    ConstantClass cls = (ConstantClass) cp.getConstant(fieldref.getClassIndex());
    String className = cls.getBytes(cp).replace('/', '.');

    ConstantNameAndType nameAndType = (ConstantNameAndType) cp.getConstant(fieldref.getNameAndTypeIndex());
    String fieldName = nameAndType.getName(cp);
    String fieldSig = nameAndType.getSignature(cp);


    XField xfield = Hierarchy.findXField(className, fieldName, fieldSig, isStatic);
    if (xfield != null && xfield.isStatic() == isStatic && isValidAccessMethod(methodSig, xfield, isLoad)) {
        access = new InnerClassAccess(methodName, methodSig, xfield, isLoad);
    }

}
 

/**
 * Verify for an inner class declared inside the 'main' method that the
 * enclosing method attribute is set correctly.
 */
public void testCheckMethodLevelNamedInnerClass()
        throws ClassNotFoundException
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.AttributeTestClassEM01$1S");
    final ConstantPool pool = clazz.getConstantPool();
    final Attribute[] encMethodAttrs = findAttribute("EnclosingMethod", clazz);
    assertTrue("Expected 1 EnclosingMethod attribute but found "
            + encMethodAttrs.length, encMethodAttrs.length == 1);
    final EnclosingMethod em = (EnclosingMethod) encMethodAttrs[0];
    final String enclosingClassName = em.getEnclosingClass().getBytes(pool);
    final String enclosingMethodName = em.getEnclosingMethod().getName(pool);
    assertTrue(
            "Expected class name to be '"+PACKAGE_BASE_SIG+"/data/AttributeTestClassEM01' but was "
                    + enclosingClassName, enclosingClassName
                    .equals(PACKAGE_BASE_SIG+"/data/AttributeTestClassEM01"));
    assertTrue("Expected method name to be 'main' but was "
            + enclosingMethodName, enclosingMethodName.equals("main"));
}
 

/**
 * Verify for an inner class declared at the type level that the
 * EnclosingMethod attribute is set correctly (i.e. to a null value)
 */
public void testCheckClassLevelNamedInnerClass()
        throws ClassNotFoundException
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.AttributeTestClassEM02$1");
    final ConstantPool pool = clazz.getConstantPool();
    final Attribute[] encMethodAttrs = findAttribute("EnclosingMethod", clazz);
    assertTrue("Expected 1 EnclosingMethod attribute but found "
            + encMethodAttrs.length, encMethodAttrs.length == 1);
    final EnclosingMethod em = (EnclosingMethod) encMethodAttrs[0];
    final String enclosingClassName = em.getEnclosingClass().getBytes(pool);
    assertTrue(
            "The class is not within a method, so method_index should be null, but it is "
                    + em.getEnclosingMethodIndex(), em
                    .getEnclosingMethodIndex() == 0);
    assertTrue(
            "Expected class name to be '"+PACKAGE_BASE_SIG+"/data/AttributeTestClassEM02' but was "
                    + enclosingClassName, enclosingClassName
                    .equals(PACKAGE_BASE_SIG+"/data/AttributeTestClassEM02"));
}
 

AttributeHTML(final String dir, final String class_name, final ConstantPool constant_pool,
        final ConstantHTML constant_html) throws IOException {
    this.class_name = class_name;
    this.constant_pool = constant_pool;
    this.constant_html = constant_html;
    file = new PrintWriter(new FileOutputStream(dir + class_name + "_attributes.html"));
    file.println("<HTML><BODY BGCOLOR=\"#C0C0C0\"><TABLE BORDER=0>");
}
 

/**
 * Override the parent method because our classname is held elsewhere.
 */
@Override
public String getClassName( final ConstantPoolGen cpg ) {
    final ConstantPool cp = cpg.getConstantPool();
    final ConstantInvokeDynamic cid = (ConstantInvokeDynamic) cp.getConstant(super.getIndex(), Const.CONSTANT_InvokeDynamic);
    return ((ConstantNameAndType) cp.getConstant(cid.getNameAndTypeIndex())).getName(cp);
}
 

/** @return type related with this instruction.
 */
@Override
public Type getType( final ConstantPoolGen cpg ) {
    final ConstantPool cp = cpg.getConstantPool();
    String name = cp.getConstantString(index, org.apache.bcel.Const.CONSTANT_Class);
    if (!name.startsWith("[")) {
        name = "L" + name + ";";
    }
    return Type.getType(name);
}
 

/**
 * This overrides the deprecated version as we know here that the referenced class
 * may legally be an array.
 *
 * @return name of the referenced class/interface
 * @throws IllegalArgumentException if the referenced class is an array (this should not happen)
 */
@Override
public String getClassName( final ConstantPoolGen cpg ) {
    final ConstantPool cp = cpg.getConstantPool();
    final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    return className.replace('/', '.');
}
 

/**
 * @return name of the referenced class/interface
 * @deprecated If the instruction references an array class,
 *    this method will return "java.lang.Object".
 *    For code generated by Java 1.5, this answer is
 *    sometimes wrong (e.g., if the "clone()" method is
 *    called on an array).  A better idea is to use
 *    the {@link #getReferenceType(ConstantPoolGen)} method, which correctly distinguishes
 *    between class types and array types.
 *
 */
@Deprecated
public String getClassName(final ConstantPoolGen cpg) {
    final ConstantPool cp = cpg.getConstantPool();
    final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    if (className.startsWith("[")) {
        // Turn array classes into java.lang.Object.
        return "java.lang.Object";
    }
    return className.replace('/', '.');
}
 

/** @return signature of referenced method/field.
 */
public String getSignature(final ConstantPoolGen cpg) {
    final ConstantPool cp = cpg.getConstantPool();
    final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
}
 

/** @return name of referenced method/field.
 */
public String getName(final ConstantPoolGen cpg) {
    final ConstantPool cp = cpg.getConstantPool();
    final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
}
 

/** @see com.puppycrawl.tools.checkstyle.bcel.IDeepVisitor */
public void visitObject(Object aObject)
{
    final JavaClass javaClass = (JavaClass) aObject;
    final ConstantPool pool = javaClass.getConstantPool();
    mCurrentPoolGen = new ConstantPoolGen(pool);
}
 

CodeHTML(final String dir, final String class_name, final Method[] methods, final ConstantPool constant_pool,
            final ConstantHTML constant_html) throws IOException {
        this.className = class_name;
//        this.methods = methods;
        this.constantPool = constant_pool;
        this.constantHtml = constant_html;
        file = new PrintWriter(new FileOutputStream(dir + class_name + "_code.html"));
        file.println("<HTML><BODY BGCOLOR=\"#C0C0C0\">");
        for (int i = 0; i < methods.length; i++) {
            writeMethod(methods[i], i);
        }
        file.println("</BODY></HTML>");
        file.close();
    }
 

/**
 * Check that we can save and load the attribute correctly.
 */
public void testAttributeSerializtion() throws ClassNotFoundException,
        IOException
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.AttributeTestClassEM02$1");
    final ConstantPool pool = clazz.getConstantPool();
    final Attribute[] encMethodAttrs = findAttribute("EnclosingMethod", clazz);
    assertTrue("Expected 1 EnclosingMethod attribute but found "
            + encMethodAttrs.length, encMethodAttrs.length == 1);
    // Write it out
    final File tfile = createTestdataFile("AttributeTestClassEM02$1.class");
    clazz.dump(tfile);
    // Read in the new version and check it is OK
    final SyntheticRepository repos2 = createRepos(".");
    final JavaClass clazz2 = repos2.loadClass("AttributeTestClassEM02$1");
    Assert.assertNotNull(clazz2); // Use the variable to avoid a warning
    final EnclosingMethod em = (EnclosingMethod) encMethodAttrs[0];
    final String enclosingClassName = em.getEnclosingClass().getBytes(pool);
    assertTrue(
            "The class is not within a method, so method_index should be null, but it is "
                    + em.getEnclosingMethodIndex(), em
                    .getEnclosingMethodIndex() == 0);
    assertTrue(
            "Expected class name to be '"+PACKAGE_BASE_SIG+"/data/AttributeTestClassEM02' but was "
                    + enclosingClassName, enclosingClassName
                    .equals(PACKAGE_BASE_SIG+"/data/AttributeTestClassEM02"));
    tfile.deleteOnExit();
}
 

/**
 * @return mnemonic for instruction with symbolic references resolved
 */
@Override
public String toString( final ConstantPool cp ) {
    final Constant c = cp.getConstant(index);
    String str = cp.constantToString(c);
    if (c instanceof ConstantClass) {
        str = str.replace('.', '/');
    }
    return org.apache.bcel.Const.getOpcodeName(super.getOpcode()) + " " + str;
}
 

/**
 * Processes constant pool entries.
 * @throws  IOException
 * @throws  ClassFormatException
 */
private final void processConstantPool () throws IOException, ClassFormatException {
    byte tag;
    final int constant_pool_count = file.readUnsignedShort();
    constant_items = new Constant[constant_pool_count];
    constant_pool = new ConstantPool(constant_items);

    // constant_pool[0] is unused by the compiler
    System.out.printf("%nConstant pool(%d):%n", constant_pool_count - 1);

    for (int i = 1; i < constant_pool_count; i++) {
        constant_items[i] = Constant.readConstant(file);
        // i'm sure there is a better way to do this
        if (i < 10) {
            System.out.printf("    #%1d = ", i);
        } else if (i <100) {
            System.out.printf("   #%2d = ", i);
        } else {
            System.out.printf("  #%d = ", i);
        }
        System.out.println(constant_items[i]);

        // All eight byte constants take up two spots in the constant pool
        tag = constant_items[i].getTag();
        if ((tag == Const.CONSTANT_Double) ||
                (tag == Const.CONSTANT_Long)) {
            i++;
        }
    }
}
 

/**
 * Add this class to allClasses. Then go through all its dependents
 * and add them to the dependents list if they are not in allClasses
 */
void addDependents(final JavaClass clazz) throws IOException {
    final String name = clazz.getClassName().replace('.', '/');
    allClasses.put(name, clazz);
    final ConstantPool pool = clazz.getConstantPool();
    for (int i = 1; i < pool.getLength(); i++) {
        final Constant cons = pool.getConstant(i);
        //System.out.println("("+i+") " + cons );
        if (cons != null && cons.getTag() == Constants.CONSTANT_Class) {
            final int idx = ((ConstantClass) pool.getConstant(i)).getNameIndex();
            final String clas = ((ConstantUtf8) pool.getConstant(idx)).getBytes();
            addClassString(clas, name);
        }
    }
}
 

/**
 * @see org.apache.bcel.classfile.Visitor
 */
public void visitConstantPool(ConstantPool aConstantPool)
{
    for (Iterator iter = mVisitors.iterator(); iter.hasNext();) {
        IDeepVisitor visitor = (IDeepVisitor) iter.next();
        Visitor v = visitor.getClassFileVisitor();
        aConstantPool.accept(v);
    }
}
 

/**
 * Dump the list of classes this class is dependent on
 */
public static void printClassDependencies(final ConstantPool pool) {
    System.out.println("Dependencies:");
    for (final String name : getClassDependencies(pool)) {
        System.out.println("\t" + name);
    }
}