1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.bcel.classfile;
19
20 /**
21 * Unknown (non-standard) attributes may be read via user-defined factory objects that can be registered with the
22 * Attribute.addAttributeReader method. These factory objects should implement this interface.
23 *
24 * @see Attribute
25 * @since 6.0
26 */
27 public interface UnknownAttributeReader {
28
29 /**
30 * When this attribute reader is added via the static method Attribute.addAttributeReader, an attribute name is
31 * associated with it. As the class file parser parses attributes, it will call various AttributeReaders based on the
32 * name of the attributes it is constructing.
33 *
34 * @param nameIndex An index into the constant pool, indexing a ConstantUtf8 that represents the name of the attribute.
35 * @param length The length of the data contained in the attribute. This is written into the constant pool and should
36 * agree with what the factory expects the length to be.
37 * @param file This is the data input that the factory needs to read its data from.
38 * @param constantPool This is the constant pool associated with the Attribute that we are constructing.
39 *
40 * @return The user-defined AttributeReader should take this data and use it to construct an attribute. In the case of
41 * errors, a null can be returned which will cause the parsing of the class file to fail.
42 *
43 * @see Attribute#addAttributeReader(String, UnknownAttributeReader)
44 */
45 Attribute createAttribute(int nameIndex, int length, java.io.DataInput file, ConstantPool constantPool);
46 }