AttributeFactory.java

/*
 *  Copyright (c) 2001-2024, Jean Tessier
 *  All rights reserved.
 *  
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  
 *      * Redistributions of source code must retain the above copyright
 *        notice, this list of conditions and the following disclaimer.
 *  
 *      * Redistributions in binary form must reproduce the above copyright
 *        notice, this list of conditions and the following disclaimer in the
 *        documentation and/or other materials provided with the distribution.
 *  
 *      * Neither the name of Jean Tessier nor the names of his contributors
 *        may be used to endorse or promote products derived from this software
 *        without specific prior written permission.
 *  
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
 *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.jeantessier.classreader.impl;

import java.io.*;

import org.apache.logging.log4j.*;

import com.jeantessier.classreader.*;

public class AttributeFactory {
    public Attribute_info create(ConstantPool constantPool, Visitable owner, DataInput in) throws IOException {
        Attribute_info result;

        int nameIndex = in.readUnsignedShort();
        if (nameIndex > 0) {
            Object entry = constantPool.get(nameIndex);

            if (entry instanceof UTF8_info utf8_info) {
                String name = utf8_info.getValue();
                LogManager.getLogger(AttributeFactory.class).debug("Attribute name index: {} ({})", nameIndex, name);

                AttributeType attributeType = AttributeType.forName(name);
                if (attributeType != null) {
                    result = attributeType.create(constantPool, owner, in, this);
                } else {
                    LogManager.getLogger(AttributeFactory.class).warn("Unknown attribute name \"{}\"", name);
                    result = new Custom_attribute(constantPool, owner, in, name);
                }
            } else {
                LogManager.getLogger(AttributeFactory.class).debug("Attribute name: {}", entry);

                LogManager.getLogger(AttributeFactory.class).warn("Unknown attribute with invalid name \"{}\"", entry);
                result = new Custom_attribute(constantPool, owner, in);
            }
        } else {
            LogManager.getLogger(AttributeFactory.class).debug("Attribute name index: {}", nameIndex);

            LogManager.getLogger(AttributeFactory.class).warn("Unknown attribute with no name (name index = {})", nameIndex);
            result = new Custom_attribute(constantPool, owner, in);
        }

        return result;
    }
}