com.packenius.datadivider.javaclass.JavaClassFileDescription Maven / Gradle / Ivy

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package com.packenius.datadivider.javaclass;

import com.packenius.dumpapi.CrossPointer;
import com.packenius.dumpapi.DumpBlock;
import com.packenius.dumpapi.DumpReader;
import com.packenius.dumpapi.MainDumpBlock;

/**
 * Creates a dump for a java class file.
 * 
 * @author Christian Packenius, 2016.
 */
public class JavaClassFileDescription extends MainDumpBlock {
    /**
     * Lädt eine Klasse an Hand ihres Inhaltes.
     * 
     * @param content Inhalt der Klasse(ndatei) als Bytearray.
     */
    public JavaClassFileDescription(DumpReader reader) {
        super(reader);

        reader.setUserObject(new Signature(reader));
        reader.setUserObject(new Version(reader));
        reader.setUserObject(new ConstantPool(reader));
        reader.setUserObject(new ClassHeader(reader));
        reader.setUserObject(new Interfaces(reader));
        reader.setUserObject(new Fields(reader));
        reader.setUserObject(new Methods(reader));
        reader.setUserObject(new Attributes(reader));

        // Prüfen, ob das Ende der Klasse erreicht wurde.
        setEndAddress(reader);
        checkEndOfData(reader);
    }

    /**
     * Prüft, ob beim ClassReader das Ende des Datenstroms erreicht wurde.
     * 
     * @param reader Klassen-Reader.
     */
    private void checkEndOfData(DumpReader reader) {
        if (!reader.isEOF()) {
            throw new IllegalArgumentException("Hinter den class-Daten stehen weitere Bytes!");
        }
    }

    /**
     * Ermittelt den Namen der beschriebenen Klasse.
     * 
     * @return Klassenname, voll qualifiziert.
     */
    public String getName() {
        ConstantPool cp = reader.getUserObject(ConstantPool.class);
        ClassHeader classHeader = reader.getUserObject(ClassHeader.class);
        return cp.getClassEntry(classHeader.thisClassIndex).getClassName();
    }

    @Override
    public String toString() {
        return "Java class file";
    }

    public MethodDescription getMethod(String name, String descriptor) {
        ConstantPool cp = reader.getUserObject(ConstantPool.class);
        return reader.getUserObject(Methods.class).getMethod(cp, name, descriptor);
    }

    @Override
    public String getDescription() {
        return "A java class file is executable within a java virtual machine.";
    }

    @Override
    public DumpBlock getCrossPointerDumpBlocks(CrossPointer crossPointer) {
        if (crossPointer instanceof ConstantPoolEntryCrossPointer) {
            ConstantPoolEntryCrossPointer cpecp = (ConstantPoolEntryCrossPointer) crossPointer;
            int cpeIndex = cpecp.constantPoolEntryIndex;
            return reader.getUserObject(ConstantPool.class).getEntry(cpeIndex);
        }
        if (crossPointer != null) {
            throw new RuntimeException("Unknown cross pointer type <" + crossPointer.getClass() + ">!");
        }
        return null;
    }

    public String dump() {
        StringBuilder sb = new StringBuilder(reader.length * 4);
        dump(sb, null, false);
        return sb.toString();
    }
}