objectstreamclass.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 2,026 行 · 第 1/5 页

	    // field mismatches impossible when matching local fields vs. self
	    throw new InternalError();
	}

	//	if (cons == null) { // - Back-ported from JDK 1.4 
	if (initClass == null) {
	    deserializeEx = new InvalidClassException(
		name, "no valid constructor");
	}
	for (int i = 0; i < fields.length; i++) {
	    if (fields[i].getField() == null) {
		defaultSerializeEx = new InvalidClassException(
		    name, "unmatched serializable field(s) declared");
	    }
	}
    }

    /**
     * Creates blank class descriptor which should be initialized via a
     * subsequent call to initProxy(), initNonProxy() or readNonProxy().
     */
    ObjectStreamClass() {
    }
    
    /**
     * Initializes class descriptor representing a proxy class.
     */
    void initProxy(Class cl, 
		   ClassNotFoundException resolveEx, 
		   ObjectStreamClass superDesc) 
	throws InvalidClassException
    {
	this.cl = cl;
	this.resolveEx = resolveEx;
	this.superDesc = superDesc;
	isProxy = true;
	serializable = true;
	suid = new Long(0);
	fields = NO_FIELDS;
	
	if (cl != null) {
	    localDesc = lookup(cl, true);
	    if (!localDesc.isProxy) {
		throw new InvalidClassException(
		    "cannot bind proxy descriptor to a non-proxy class");
	    }
	    name = localDesc.name;
	    externalizable = localDesc.externalizable;

	    // cons = localDesc.cons; // - Back-ported from JDK 1.4 
	    initClass = localDesc.initClass;

	    writeReplaceMethod = localDesc.writeReplaceMethod;
	    readResolveMethod = localDesc.readResolveMethod;
	    deserializeEx = localDesc.deserializeEx;
	}
	fieldRefl = getReflector(fields, localDesc);
    }
    
    /**
     * Initializes class descriptor representing a non-proxy class.
     */
    void initNonProxy(ObjectStreamClass model, 
		      Class cl, 
		      ClassNotFoundException resolveEx,
		      ObjectStreamClass superDesc)
	throws InvalidClassException
    {
	this.cl = cl;
	this.resolveEx = resolveEx;
	this.superDesc = superDesc;
	name = model.name;
	suid = new Long(model.getSerialVersionUID());
	isProxy = false;
	serializable = model.serializable;
	externalizable = model.externalizable;
	hasBlockExternalData = model.hasBlockExternalData;
	hasWriteObjectData = model.hasWriteObjectData;
	fields = model.fields;
	primDataSize = model.primDataSize;
	numObjFields = model.numObjFields;
	
	if (cl != null) {
	    localDesc = lookup(cl, true);
	    if (localDesc.isProxy) {
		throw new InvalidClassException(
		    "cannot bind non-proxy descriptor to a proxy class");
	    }
	    
	    if (serializable == localDesc.serializable &&
		!cl.isArray() &&
		suid.longValue() != localDesc.getSerialVersionUID())
	    {
		throw new InvalidClassException(localDesc.name, 
		    "local class incompatible: " +
		    "stream classdesc serialVersionUID = " + suid +
		    ", local class serialVersionUID = " +
		    localDesc.getSerialVersionUID());
	    }
		
	    if (!classNamesEqual(name, localDesc.name)) {
		throw new InvalidClassException(localDesc.name,
		    "local class name incompatible with stream class " +
		    "name \"" + name + "\"");
	    }
	    
	    if ((serializable == localDesc.serializable) &&
		(externalizable != localDesc.externalizable))
	    {
		throw new InvalidClassException(localDesc.name, 
		    "Serializable incompatible with Externalizable");
	    }

	    if ((serializable != localDesc.serializable) ||
		(externalizable != localDesc.externalizable) ||
		!(serializable || externalizable))
	    {
		deserializeEx = new InvalidClassException(localDesc.name,
		    "class invalid for deserialization");
	    }
	    
	    // cons = localDesc.cons;  // - Back-ported from JDK 1.4 
	    initClass = localDesc.initClass;

	    writeObjectMethod = localDesc.writeObjectMethod;
	    readObjectMethod = localDesc.readObjectMethod;
	    readObjectNoDataMethod = localDesc.readObjectNoDataMethod;
	    writeReplaceMethod = localDesc.writeReplaceMethod;
	    readResolveMethod = localDesc.readResolveMethod;
	    if (deserializeEx == null) {
		deserializeEx = localDesc.deserializeEx;
	    }
	}
	fieldRefl = getReflector(fields, localDesc);
	// reassign to matched fields so as to reflect local unshared settings
	fields = fieldRefl.getFields();
    }
    
    /**
     * Reads non-proxy class descriptor information from given input stream.
     * The resulting class descriptor is not fully functional; it can only be
     * used as input to the ObjectInputStream.resolveClass() and
     * ObjectStreamClass.initNonProxy() methods.
     */
    void readNonProxy(ObjectInputStream in) 
	throws IOException, ClassNotFoundException
    {
	name = in.readUTF();
	suid = new Long(in.readLong());
	isProxy = false;

	byte flags = in.readByte();
	externalizable = 
	    ((flags & ObjectStreamConstants.SC_EXTERNALIZABLE) != 0);
	serializable = (externalizable ||
	    ((flags & ObjectStreamConstants.SC_SERIALIZABLE) != 0));
	hasWriteObjectData = 
	    ((flags & ObjectStreamConstants.SC_WRITE_METHOD) != 0);
	hasBlockExternalData = 
	    ((flags & ObjectStreamConstants.SC_BLOCK_DATA) != 0);
	
	int numFields = in.readShort();
	fields = (numFields > 0) ? 
	    new ObjectStreamField[numFields] : NO_FIELDS;
	for (int i = 0; i < numFields; i++) {
	    char tcode = (char) in.readByte();
	    String name = in.readUTF();
	    String signature = ((tcode == 'L') || (tcode == '[')) ?
		in.readTypeString() : new String(new char[] { tcode });
	    fields[i] = new ObjectStreamField(name, signature, false);
	}
	computeFieldOffsets();
    }

    /**
     * Writes non-proxy class descriptor information to given output stream.
     */
    void writeNonProxy(ObjectOutputStream out) throws IOException {
	out.writeUTF(name);
	out.writeLong(getSerialVersionUID());

	byte flags = 0;
	if (externalizable) {
	    flags |= ObjectStreamConstants.SC_EXTERNALIZABLE;
	    int protocol = out.getProtocolVersion();
	    if (protocol != ObjectStreamConstants.PROTOCOL_VERSION_1) {
		flags |= ObjectStreamConstants.SC_BLOCK_DATA;
	    }
	} else if (serializable) {
	    flags |= ObjectStreamConstants.SC_SERIALIZABLE;
	}
	if (hasWriteObjectData) {
	    flags |= ObjectStreamConstants.SC_WRITE_METHOD;
	}
	out.writeByte(flags);
	
	out.writeShort(fields.length);
	for (int i = 0; i < fields.length; i++) {
	    ObjectStreamField f = fields[i];
	    out.writeByte(f.getTypeCode());
	    out.writeUTF(f.getName());
	    if (!f.isPrimitive()) {
		out.writeTypeString(f.getTypeString());
	    }
	}
    }
    
    /**
     * Returns ClassNotFoundException (if any) thrown while attempting to
     * resolve local class corresponding to this class descriptor.
     */
    ClassNotFoundException getResolveException() {
	return resolveEx;
    }

    /**
     * Throws an InvalidClassException if object instances referencing this
     * class descriptor should not be allowed to deserialize.
     */
    void checkDeserialize() throws InvalidClassException {
	if (deserializeEx != null) {
	    throw deserializeEx;
	}
    }
    
    /**
     * Throws an InvalidClassException if objects whose class is represented by
     * this descriptor should not be permitted to use default serialization
     * (e.g., if the class declares serializable fields that do not correspond
     * to actual fields, and hence must use the GetField API).
     */
    void checkDefaultSerialize() throws InvalidClassException {
	if (defaultSerializeEx != null) {
	    throw defaultSerializeEx;
	}
    }

    /**
     * Returns superclass descriptor.  Note that on the receiving side, the
     * superclass descriptor may be bound to a class that is not a superclass
     * of the subclass descriptor's bound class.
     */
    ObjectStreamClass getSuperDesc() {
	return superDesc;
    }
    
    /**
     * Returns the "local" class descriptor for the class associated with this
     * class descriptor (i.e., the result of
     * ObjectStreamClass.lookup(this.forClass())) or null if there is no class
     * associated with this descriptor.
     */
    ObjectStreamClass getLocalDesc() {
	return localDesc;
    }

    /**
     * Returns arrays of ObjectStreamFields representing the serializable
     * fields of the represented class.  If copy is true, a clone of this class
     * descriptor's field array is returned, otherwise the array itself is
     * returned.
     */
    ObjectStreamField[] getFields(boolean copy) {
	return copy ? (ObjectStreamField[]) fields.clone() : fields;
    }
    
    /**
     * Looks up a serializable field of the represented class by name and type.
     * A specified type of null matches all types, Object.class matches all
     * non-primitive types, and any other non-null type matches assignable
     * types only.  Returns matching field, or null if no match found.
     */
    ObjectStreamField getField(String name, Class type) {
	for (int i = 0; i < fields.length; i++) {
	    ObjectStreamField f = fields[i];
	    if (f.getName().equals(name)) {
		if (type == null) 
		{
		    return f;
                } else if (type == Object.class) {
                    if (!f.isPrimitive()) {
                        return f;
                    }
		} else {
		    Class ftype = f.getType();
		    if (ftype != null && type.isAssignableFrom(ftype)) {
		        return f;
		    }
                }
	    }
	}
	return null;
    }

    /**
     * Returns true if class descriptor represents a dynamic proxy class, false
     * otherwise.
     */
    boolean isProxy() {
	return isProxy;
    }
    
    /**
     * Returns true if represented class implements Externalizable, false
     * otherwise.
     */
    boolean isExternalizable() {
	return externalizable;
    }
    
    /**
     * Returns true if represented class implements Serializable, false
     * otherwise.
     */
    boolean isSerializable() {
	return serializable;
    }

    /**
     * Returns true if class descriptor represents externalizable class that
     * has written its data in 1.2 (block data) format, false otherwise.
     */
    boolean hasBlockExternalData() {
	return hasBlockExternalData;
    }
    
    /**
     * Returns true if class descriptor represents serializable (but not
     * externalizable) class which has written its data via a custom
     * writeObject() method, false otherwise.
     */
    boolean hasWriteObjectData() {
	return hasWriteObjectData;
    }
    
    /**
     * Returns true if represented class is serializable/externalizable and can
     * be instantiated by the serialization runtime--i.e., if it is
     * externalizable and defines a public no-arg constructor, or if it is
     * non-externalizable and its first non-serializable superclass defines an
     * accessible no-arg constructor.  Otherwise, returns false.
     */
    boolean isInstantiable() {
      // return (cons != null); // - Back-ported from JDK 1.4 
      return (initClass != null);
    }
    
    /**
     * Returns true if represented class is serializable (but not
     * externalizable) and defines a conformant writeObject method.  Otherwise,
     * returns false.
     */
    boolean hasWriteObjectMethod() {
	return (writeObjectMethod != null);
    }
    
    /**
     * Returns true if represented class is serializable (but not
     * externalizable) and defines a conformant readObject method.  Otherwise,
     * returns false.
     */
    boolean hasReadObjectMethod() {
	return (readObjectMethod != null);
    }
    
    /**
     * Returns true if represented class is serializable (but not
     * externalizable) and defines a conformant readObjectNoData method.
     * Otherwise, returns false.
     */
    boolean hasReadObjectNoDataMethod() {
	return (readObjectNoDataMethod != null);
    }
    
    /**
     * Returns true if represented class is serializable or externalizable and
     * defines a conformant writeReplace method.  Otherwise, returns false.
     */
    boolean hasWriteReplaceMethod() {
	return (writeReplaceMethod != null);
    }
    
    /**
     * Returns true if represented class is serializable or externalizable and
     * defines a conformant readResolve method.  Otherwise, returns false.
     */
    boolean hasReadResolveMethod() {
	return (readResolveMethod != null);
    }
    
    /**
     * Creates a new instance of the represented class.  If the class is
     * externalizable, invokes its public no-arg constructor; otherwise, if the
     * class is serializable, invokes the no-arg constructor of the first
     * non-serializable superclass.  Throws UnsupportedOperationException if
     * this class descriptor is not associated with a class, if the associated
     * class is non-serializable or if the appropriate no-arg constructor is
     * inaccessible/unavailable.
     */
    Object newInstance()
	throws InstantiationException, InvocationTargetException,
	       UnsupportedOperationException, IllegalAccessException 
    {
      /* // - Back-ported from JDK 1.4 
	if (cons != null) {
	    try {