public static Attribute readAttribute()

in src/main/java/org/apache/bcel/classfile/Attribute.java [111:201]
79 lines of code
33 McCabe index (conditional complexity)

    public static Attribute readAttribute(final DataInput dataInput, final ConstantPool constantPool) throws IOException {
        byte tag = Const.ATTR_UNKNOWN; // Unknown attribute
        // Get class name from constant pool via 'name_index' indirection
        final int nameIndex = dataInput.readUnsignedShort();
        final String name = constantPool.getConstantUtf8(nameIndex).getBytes();

        // Length of data in bytes
        final int length = dataInput.readInt();

        // Compare strings to find known attribute
        for (byte i = 0; i < Const.KNOWN_ATTRIBUTES; i++) {
            if (name.equals(Const.getAttributeName(i))) {
                tag = i; // found!
                break;
            }
        }

        // Call proper constructor, depending on 'tag'
        switch (tag) {
        case Const.ATTR_UNKNOWN:
            final Object r = READERS.get(name);
            if (r instanceof UnknownAttributeReader) {
                return ((UnknownAttributeReader) r).createAttribute(nameIndex, length, dataInput, constantPool);
            }
            return new Unknown(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_CONSTANT_VALUE:
            return new ConstantValue(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_SOURCE_FILE:
            return new SourceFile(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_CODE:
            return new Code(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_EXCEPTIONS:
            return new ExceptionTable(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_LINE_NUMBER_TABLE:
            return new LineNumberTable(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_LOCAL_VARIABLE_TABLE:
            return new LocalVariableTable(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_INNER_CLASSES:
            return new InnerClasses(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_SYNTHETIC:
            return new Synthetic(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_DEPRECATED:
            return new Deprecated(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_PMG:
            return new PMGClass(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_SIGNATURE:
            return new Signature(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_STACK_MAP:
            // old style stack map: unneeded for JDK5 and below;
            // illegal(?) for JDK6 and above. So just delete with a warning.
            println("Warning: Obsolete StackMap attribute ignored.");
            return new Unknown(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_RUNTIME_VISIBLE_ANNOTATIONS:
            return new RuntimeVisibleAnnotations(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_RUNTIME_INVISIBLE_ANNOTATIONS:
            return new RuntimeInvisibleAnnotations(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS:
            return new RuntimeVisibleParameterAnnotations(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_RUNTIME_INVISIBLE_PARAMETER_ANNOTATIONS:
            return new RuntimeInvisibleParameterAnnotations(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_ANNOTATION_DEFAULT:
            return new AnnotationDefault(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_LOCAL_VARIABLE_TYPE_TABLE:
            return new LocalVariableTypeTable(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_ENCLOSING_METHOD:
            return new EnclosingMethod(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_STACK_MAP_TABLE:
            // read new style stack map: StackMapTable. The rest of the code
            // calls this a StackMap for historical reasons.
            return new StackMap(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_BOOTSTRAP_METHODS:
            return new BootstrapMethods(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_METHOD_PARAMETERS:
            return new MethodParameters(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_MODULE:
            return new Module(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_MODULE_PACKAGES:
            return new ModulePackages(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_MODULE_MAIN_CLASS:
            return new ModuleMainClass(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_NEST_HOST:
            return new NestHost(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_NEST_MEMBERS:
            return new NestMembers(nameIndex, length, dataInput, constantPool);
        case Const.ATTR_RECORD:
            return new Record(nameIndex, length, dataInput, constantPool);
        default:
            // Never reached
            throw new IllegalStateException("Unrecognized attribute type tag parsed: " + tag);
        }
    }