com.packenius.datadivider.javaclass.attr.ConstantValueAttribute Maven / Gradle / Ivy

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package com.packenius.datadivider.javaclass.attr;

import com.packenius.datadivider.javaclass.ConstantPool;
import com.packenius.datadivider.javaclass.ConstantPoolEntryCrossPointer;
import com.packenius.datadivider.javaclass.cp.ConstantPoolConst;
import com.packenius.dumpapi.DumpReader;
import com.packenius.dumpapi.DumpReader.BigEndianUnsigned2ByteInteger;

/**
 * Attribut mit der Darstellung eines konstanten Wertes.
 * @author Christian Packenius, 2016.
 */
public class ConstantValueAttribute extends AttributeDescription {
    private final int index;

    /**
     * Dargestellter Konstanter Wert aus dem Konstantenpool.
     */
    public final ConstantPoolConst constValue;

    /**
     * Konstruktor.
     */
    public ConstantValueAttribute(int length, DumpReader reader) {
        super(reader, length);

        ConstantPool cp = reader.getUserObject(ConstantPool.class);

        if (length != 2) {
            throw new RuntimeException("ConstantValue attribute must have length of 2!");
        }

        BigEndianUnsigned2ByteInteger indexDumpBlock = reader.readBigEndianU2("Const value index: ###DEC##");
        indexDumpBlock.setCrossPointer(new ConstantPoolEntryCrossPointer(indexDumpBlock.value));
        index = indexDumpBlock.value;

        constValue = (ConstantPoolConst) cp.getEntry(index);

        setEndAddress(reader);
    }

    /**
     * @see com.packenius.datadivider.javaclass.attr.AttributeDescription#getName()
     */
    @Override
    public String getName() {
        return "ConstantValue";
    }

    @Override
    public String toString() {
        return "Constant Value Attribute";
    }

    @Override
    public String getDescription() {
        return "The ConstantValue attribute is a fixed-length attribute in the attributes table of "
                + "a field_info structure. A ConstantValue attribute represents the value of "
                + "a constant expression.";
    }
}