001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.bcel.classfile; 019 020/** 021 * Unknown (non-standard) attributes may be read via user-defined factory 022 * objects that can be registered with the Attribute.addAttributeReader 023 * method. These factory objects should implement this interface. 024 * 025 * @see Attribute 026 * @since 6.0 027 */ 028public interface UnknownAttributeReader { 029 030 /** 031 * When this attribute reader is added via the static method Attribute.addAttributeReader, 032 * an attribute name is associated with it. As the class file parser parses attributes, 033 * it will call various AttributeReaders based on the name of the attributes it is constructing. 034 * 035 * @param name_index An index into the constant pool, indexing a ConstantUtf8 036 * that represents the name of the attribute. 037 * @param length The length of the data contained in the attribute. This is written 038 * into the constant pool and should agree with what the factory expects the length to be. 039 * @param file This is the data input that the factory needs to read its data from. 040 * @param constant_pool This is the constant pool associated with the Attribute that we are constructing. 041 * 042 * @return The user-defined AttributeReader should take this data and use 043 * it to construct an attribute. In the case of errors, a null can be 044 * returned which will cause the parsing of the class file to fail. 045 * 046 * @see Attribute#addAttributeReader(String, UnknownAttributeReader) 047 */ 048 Attribute createAttribute( int name_index, int length, java.io.DataInput file, ConstantPool constant_pool ); 049}