constpool.java

Javassist是一个开源的分析、编辑和创建Java字节码的类库。是由东京技术学院的数学和计算机科学系的 Shigeru Chiba 所创建的。它已加入了开放源代码JBoss 应用服务器项目,通过使

    }

    /**
     * Reads <code>CONSTANT_Float_info</code> structure
     * at the given index.
     *
     * @return the value specified by this entry.
     */
    public float getFloatInfo(int index) {
        FloatInfo i = (FloatInfo)getItem(index);
        return i.value;
    }

    /**
     * Reads <code>CONSTANT_Long_info</code> structure
     * at the given index.
     *
     * @return the value specified by this entry.
     */
    public long getLongInfo(int index) {
        LongInfo i = (LongInfo)getItem(index);
        return i.value;
    }

    /**
     * Reads <code>CONSTANT_Double_info</code> structure
     * at the given index.
     *
     * @return the value specified by this entry.
     */
    public double getDoubleInfo(int index) {
        DoubleInfo i = (DoubleInfo)getItem(index);
        return i.value;
    }

    /**
     * Reads <code>CONSTANT_String_info</code> structure
     * at the given index.
     *
     * @return the string specified by <code>string_index</code>.
     */
    public String getStringInfo(int index) {
        StringInfo si = (StringInfo)getItem(index);
        return getUtf8Info(si.string);
    }

    /**
     * Reads <code>CONSTANT_utf8_info</code> structure
     * at the given index.
     *
     * @return the string specified by this entry.
     */
    public String getUtf8Info(int index) {
        Utf8Info utf = (Utf8Info)getItem(index);
        return utf.string;
    }

    /**
     * Determines whether <code>CONSTANT_Methodref_info</code>
     * structure at the given index represents the constructor
     * of the given class.
     *
     * @return          the <code>descriptor_index</code> specifying
     *                  the type descriptor of the that constructor.
     *                  If it is not that constructor,
     *                  <code>isConstructor()</code> returns 0.
     */
    public int isConstructor(String classname, int index) {
        return isMember(classname, MethodInfo.nameInit, index);
    }

    /**
     * Determines whether <code>CONSTANT_Methodref_info</code>,
     * <code>CONSTANT_Fieldref_info</code>, or
     * <code>CONSTANT_InterfaceMethodref_info</code> structure
     * at the given index represents the member with the specified
     * name and declaring class.
     *
     * @param classname         the class declaring the member
     * @param membername        the member name
     * @param index             the index into the constant pool table
     *
     * @return          the <code>descriptor_index</code> specifying
     *                  the type descriptor of that member.
     *                  If it is not that member,
     *                  <code>isMember()</code> returns 0.
     */
    public int isMember(String classname, String membername, int index) {
        MemberrefInfo minfo = (MemberrefInfo)getItem(index);
        if (getClassInfo(minfo.classIndex).equals(classname)) {
            NameAndTypeInfo ntinfo
                = (NameAndTypeInfo)getItem(minfo.nameAndTypeIndex);
            if (getUtf8Info(ntinfo.memberName).equals(membername))
                return ntinfo.typeDescriptor;
        }

        return 0;       // false
    }

    private int addItem(ConstInfo info) {
        items.addElement(info);
        return numOfItems++;
    }

    /**
     * Copies the n-th item in this ConstPool object into the destination
     * ConstPool object.
     * The class names that the item refers to are renamed according
     * to the given map.
     *
     * @param n                 the <i>n</i>-th item
     * @param dest              destination constant pool table
     * @param classnames        the map or null.
     * @return the index of the copied item into the destination ClassPool.
     */
    public int copy(int n, ConstPool dest, Map classnames) {
        if (n == 0)
            return 0;

        ConstInfo info = getItem(n);
        return info.copy(this, dest, classnames);
    }

    int addConstInfoPadding() {
        return addItem(new ConstInfoPadding());
    }

    /**
     * Adds a new <code>CONSTANT_Class_info</code> structure.
     *
     * <p>This also adds a <code>CONSTANT_Utf8_info</code> structure
     * for storing the class name.
     *
     * @return          the index of the added entry.
     */
    public int addClassInfo(CtClass c) {
        if (c == THIS)
            return thisClassInfo;
        else if (!c.isArray())
            return addClassInfo(c.getName());
        else {
            // an array type is recorded in the hashtable with
            // the key "[L<classname>;" instead of "<classname>".
            //
            // note: toJvmName(toJvmName(c)) is equal to toJvmName(c).

            return addClassInfo(Descriptor.toJvmName(c));
        }
    }

    /**
     * Adds a new <code>CONSTANT_Class_info</code> structure.
     *
     * <p>This also adds a <code>CONSTANT_Utf8_info</code> structure
     * for storing the class name.
     *
     * @param qname     a fully-qualified class name
     *                  (or the JVM-internal representation of that name).
     * @return          the index of the added entry.
     */
    public int addClassInfo(String qname) {
        ClassInfo info = (ClassInfo)classes.get(qname);
        if (info != null)
            return info.index;
        else {
            int utf8 = addUtf8Info(Descriptor.toJvmName(qname));
            info = new ClassInfo(utf8, numOfItems);
            classes.put(qname, info);
            return addItem(info);
        }
    }

    /**
     * Adds a new <code>CONSTANT_NameAndType_info</code> structure.
     *
     * <p>This also adds <code>CONSTANT_Utf8_info</code> structures.
     *
     * @param name      <code>name_index</code>
     * @param type      <code>descriptor_index</code>
     * @return          the index of the added entry.
     */
    public int addNameAndTypeInfo(String name, String type) {
        return addNameAndTypeInfo(addUtf8Info(name), addUtf8Info(type));
    }

    /**
     * Adds a new <code>CONSTANT_NameAndType_info</code> structure.
     *
     * @param name      <code>name_index</code>
     * @param type      <code>descriptor_index</code>
     * @return          the index of the added entry.
     */
    public int addNameAndTypeInfo(int name, int type) {
        return addItem(new NameAndTypeInfo(name, type));
    }

    /**
     * Adds a new <code>CONSTANT_Fieldref_info</code> structure.
     *
     * <p>This also adds a new <code>CONSTANT_NameAndType_info</code>
     * structure.
     *
     * @param classInfo         <code>class_index</code>
     * @param name              <code>name_index</code>
     *                          of <code>CONSTANT_NameAndType_info</code>.
     * @param type              <code>descriptor_index</code>
     *                          of <code>CONSTANT_NameAndType_info</code>.
     * @return          the index of the added entry.
     */
    public int addFieldrefInfo(int classInfo, String name, String type) {
        int nt = addNameAndTypeInfo(name, type);
        return addFieldrefInfo(classInfo, nt);
    }

    /**
     * Adds a new <code>CONSTANT_Fieldref_info</code> structure.
     *
     * @param classInfo         <code>class_index</code>
     * @param nameAndTypeInfo   <code>name_and_type_index</code>.
     * @return          the index of the added entry.
     */
    public int addFieldrefInfo(int classInfo, int nameAndTypeInfo) {
        return addItem(new FieldrefInfo(classInfo, nameAndTypeInfo));
    }

    /**
     * Adds a new <code>CONSTANT_Methodref_info</code> structure.
     *
     * <p>This also adds a new <code>CONSTANT_NameAndType_info</code>
     * structure.
     *
     * @param classInfo         <code>class_index</code>
     * @param name              <code>name_index</code>
     *                          of <code>CONSTANT_NameAndType_info</code>.
     * @param type              <code>descriptor_index</code>
     *                          of <code>CONSTANT_NameAndType_info</code>.
     * @return          the index of the added entry.
     */
    public int addMethodrefInfo(int classInfo, String name, String type) {
        int nt = addNameAndTypeInfo(name, type);
        return addMethodrefInfo(classInfo, nt);
    }

    /**
     * Adds a new <code>CONSTANT_Methodref_info</code> structure.
     *
     * @param classInfo         <code>class_index</code>
     * @param nameAndTypeInfo   <code>name_and_type_index</code>.
     * @return          the index of the added entry.
     */
    public int addMethodrefInfo(int classInfo, int nameAndTypeInfo) {
        return addItem(new MethodrefInfo(classInfo, nameAndTypeInfo));
    }

    /**
     * Adds a new <code>CONSTANT_InterfaceMethodref_info</code>
     * structure.
     *
     * <p>This also adds a new <code>CONSTANT_NameAndType_info</code>
     * structure.
     *
     * @param classInfo         <code>class_index</code>
     * @param name              <code>name_index</code>
     *                          of <code>CONSTANT_NameAndType_info</code>.
     * @param type              <code>descriptor_index</code>
     *                          of <code>CONSTANT_NameAndType_info</code>.
     * @return          the index of the added entry.
     */
    public int addInterfaceMethodrefInfo(int classInfo, String name,
                                         String type) {
        int nt = addNameAndTypeInfo(name, type);
        return addInterfaceMethodrefInfo(classInfo, nt);
    }

    /**
     * Adds a new <code>CONSTANT_InterfaceMethodref_info</code>
     * structure.
     *
     * @param classInfo         <code>class_index</code>
     * @param nameAndTypeInfo   <code>name_and_type_index</code>.
     * @return          the index of the added entry.
     */
    public int addInterfaceMethodrefInfo(int classInfo,
                                         int nameAndTypeInfo) {
        return addItem(new InterfaceMethodrefInfo(classInfo,
                                                  nameAndTypeInfo));
    }

    /**
     * Adds a new <code>CONSTANT_String_info</code>
     * structure.
     *
     * <p>This also adds a new <code>CONSTANT_Utf8_info</code>
     * structure.
     *
     * @return          the index of the added entry.
     */
    public int addStringInfo(String str) {
        return addItem(new StringInfo(addUtf8Info(str)));
    }

    /**
     * Adds a new <code>CONSTANT_Integer_info</code>
     * structure.
     *
     * @return          the index of the added entry.
     */
    public int addIntegerInfo(int i) {
        return addItem(new IntegerInfo(i));
    }

    /**
     * Adds a new <code>CONSTANT_Float_info</code>
     * structure.
     *
     * @return          the index of the added entry.
     */
    public int addFloatInfo(float f) {
        return addItem(new FloatInfo(f));
    }

    /**
     * Adds a new <code>CONSTANT_Long_info</code>
     * structure.
     *
     * @return          the index of the added entry.
     */
    public int addLongInfo(long l) {
        int i = addItem(new LongInfo(l));
        addItem(new ConstInfoPadding());
        return i;
    }

    /**
     * Adds a new <code>CONSTANT_Double_info</code>
     * structure.
     *
     * @return          the index of the added entry.
     */
    public int addDoubleInfo(double d) {
        int i = addItem(new DoubleInfo(d));
        addItem(new ConstInfoPadding());
        return i;
    }

    /**
     * Adds a new <code>CONSTANT_Utf8_info</code>
     * structure.
     *
     * <p>If the given utf8 string has been already recorded in the
     * table, then this method does not add a new entry to avoid adding
     * a duplicated entry.
     * Instead, it returns the index of the entry already recorded.
     *
     * @return          the index of the added entry.
     */
    public int addUtf8Info(String utf8) {
        Utf8Info info = (Utf8Info)strings.get(utf8);
        if (info != null)
            return info.index;
        else {
            info = new Utf8Info(utf8, numOfItems);
            strings.put(utf8, info);
            return addItem(info);
        }
    }

    /**
     * Get all the class names.
     *
     * @return a set of class names
     */
    public Set getClassNames()
    {
        HashSet result = new HashSet();
        LongVector v = items;
        int size = numOfItems;
        for (int i = 1; i < size; ++i) {
            String className = ((ConstInfo) v.elementAt(i)).getClassName(this);
            if (className != null)
               result.add(className);
        }
        return result;
    }

    /**
     * Replaces all occurrences of a class name.
     *
     * @param oldName           the replaced name (JVM-internal representation).
     * @param newName           the substituted name (JVM-internal representation).
     */
    public void renameClass(String oldName, String newName) {
        LongVector v = items;
        int size = numOfItems;
        classes = new HashMap(classes.size() * 2);
        for (int i = 1; i < size; ++i) {
            ConstInfo ci = (ConstInfo)v.elementAt(i);
            ci.renameClass(this, oldName, newName);
            ci.makeHashtable(this);
        }
    }

    /**
     * Replaces all occurrences of class names.
     *
     * @param classnames        specifies pairs of replaced and substituted
     *                          name.
     */
    public void renameClass(Map classnames) {
        LongVector v = items;
        int size = numOfItems;
        classes = new HashMap(classes.size() * 2);
        for (int i = 1; i < size; ++i) {
            ConstInfo ci = (ConstInfo)v.elementAt(i);
            ci.renameClass(this, classnames);
            ci.makeHashtable(this);
        }
    }

    private void read(DataInputStream in) throws IOException {
        int n = in.readUnsignedShort();

        items = new LongVector(n);
        numOfItems = 0;
        addItem(null);          // index 0 is reserved by the JVM.

        while (--n > 0) {       // index 0 is reserved by JVM
            int tag = readOne(in);
            if ((tag == LongInfo.tag) || (tag == DoubleInfo.tag)) {
                addItem(new ConstInfoPadding());
                --n;
            }
        }

        int i = 1;
        while (true) {
            ConstInfo info = (ConstInfo)items.elementAt(i++);
            if (info == null)
                break;
            else
                info.makeHashtable(this);
        }
    }

    private int readOne(DataInputStream in) throws IOException {
        ConstInfo info;
        int tag = in.readUnsignedByte();
        switch (tag) {
        case Utf8Info.tag :                     // 1
            info = new Utf8Info(in, numOfItems);
            strings.put(((Utf8Info)info).string, info);
            break;
        case IntegerInfo.tag :                  // 3
            info = new IntegerInfo(in);
            break;
        case FloatInfo.tag :                    // 4
            info = new FloatInfo(in);
            break;
        case LongInfo.tag :                     // 5
            info = new LongInfo(in);
            break;
        case DoubleInfo.tag :                   // 6
            info = new DoubleInfo(in);
            break;
        case ClassInfo.tag :                    // 7
            info = new ClassInfo(in, numOfItems);
            // classes.put(<classname>, info);
            break;
        case StringInfo.tag :                   // 8
            info = new StringInfo(in);
            break;
        case FieldrefInfo.tag :                 // 9
            info = new FieldrefInfo(in);
            break;
        case MethodrefInfo.tag :                // 10
            info = new MethodrefInfo(in);
            break;
        case InterfaceMethodrefInfo.tag :       // 11
            info = new InterfaceMethodrefInfo(in);
            break;
        case NameAndTypeInfo.tag :              // 12
            info = new NameAndTypeInfo(in);