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/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

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package com.sun.org.apache.bcel.internal.classfile;

/**

 * Unknown (non-standard) attributes may be read via user-defined factory

 * objects that can be registered with the Attribute.addAttributeReader

 * method. These factory objects should implement this interface.

 *

 * @see Attribute

 * @version $Id: UnknownAttributeReader.java 1747278 2016-06-07 17:28:43Z britter $

 * @since 6.0

 */

public interface UnknownAttributeReader {

    /**

     * When this attribute reader is added via the static method Attribute.addAttributeReader,

     * an attribute name is associated with it. As the class file parser parses attributes,

     * it will call various AttributeReaders based on the name of the attributes it is constructing.

     *

     * @param name_index    An index into the constant pool, indexing a ConstantUtf8

     *                      that represents the name of the attribute.

     * @param length        The length of the data contained in the attribute. This is written

     *                      into the constant pool and should agree with what the factory expects the length to be.

     * @param file          This is the data input that the factory needs to read its data from.

     * @param constant_pool This is the constant pool associated with the Attribute that we are constructing.

     *

     * @return The user-defined AttributeReader should take this data and use

     * it to construct an attribute.  In the case of errors, a null can be

     * returned which will cause the parsing of the class file to fail.

     *

     * @see Attribute#addAttributeReader(String, UnknownAttributeReader)

     */

    Attribute createAttribute( int name_index, int length, java.io.DataInput file, ConstantPool constant_pool );

}