rice.p2p.util
Class XMLObjectInputStream

java.lang.Object
  java.io.InputStream
      java.io.ObjectInputStream
          rice.p2p.util.XMLObjectInputStream

All Implemented Interfaces:

java.io.Closeable, java.io.DataInput, java.io.ObjectInput, java.io.ObjectStreamConstants

public class XMLObjectInputStream

extends java.io.ObjectInputStream

XMLObjectInputStreamm is an extension of ObjectInputStreamm which provides for deserialization for objects which have been converted to XML via a XMLObjectOutputStream. This class supports all of the features of the ObjectInputStreamm, including serialization support for any Java object graph implementing the Serializable interface, support for Externalizable classes, custom deserialization via the readObject() method, class evolution via the readObjectNoData() method, alternate field reading mechanisms via the readFields() method, support for the readUnshared method, and dynamic object replacement via the readResolve() method. The format of the XML data to be read in should conform to the JSX XML Schema, available online at http://www.jsx.org/jsx.xsd. This class is designed to be able to read objects serialized using JSX, however, this has not been fully tested and bugs may be encountered.

Version:

$Id: XMLObjectInputStream.java 3039 2006-02-07 12:20:12Z jstewart $

Author:

Alan Mislove

Nested Class Summary

class

XMLObjectInputStream.GetField This class is an implementation of GetField which is compatible with the XMLObjectInputStreamm.

Field Summary

protected static SoftHashMap	CONSTRUCTORS A cache of constructors, mapping classes to serialization constructors
protected java.util.Stack	currentClasses The stack of class types which are being read off of the stream
protected java.util.Stack	currentObjects The stack of objects which are currently being read off of the stream
protected int	depth The depth at which we are currently at in the object tree
protected static SoftHashMap	READ_OBJECTS The hashmap of readObject methods, mapping Class->Method
protected static SoftHashMap	READ_RESOLVES The hashmap of readResolve methods, mapping Class->Method
protected XMLReader	reader The underlying reader, which parses the XML
protected java.util.Hashtable	references The hashtable of references, which is updated each time a new object is read off of the stream.
protected sun.reflect.ReflectionFactory	reflFactory The ReflectionFactory, which allows for prividged construction of objects
protected rice.p2p.util.XMLObjectInputStream.ValidationList	vlist The list of validation objects waiting for the entire object graph to be read in

Fields inherited from interface java.io.ObjectStreamConstants

baseWireHandle, PROTOCOL_VERSION_1, PROTOCOL_VERSION_2, SC_BLOCK_DATA, SC_ENUM, SC_EXTERNALIZABLE, SC_SERIALIZABLE, SC_WRITE_METHOD, STREAM_MAGIC, STREAM_VERSION, SUBCLASS_IMPLEMENTATION_PERMISSION, SUBSTITUTION_PERMISSION, TC_ARRAY, TC_BASE, TC_BLOCKDATA, TC_BLOCKDATALONG, TC_CLASS, TC_CLASSDESC, TC_ENDBLOCKDATA, TC_ENUM, TC_EXCEPTION, TC_LONGSTRING, TC_MAX, TC_NULL, TC_OBJECT, TC_PROXYCLASSDESC, TC_REFERENCE, TC_RESET, TC_STRING

Constructor Summary

XMLObjectInputStream(java.io.InputStream in)
Constructor which reads data from the given input stream in order deserialize objects.

Method Summary

void	close() Method which closes the underlying input stream for reading.
void	defaultReadObject() Method which can be called by objects if they have a readObject() method.
protected java.lang.Class	getClass(java.lang.String name) Method which returns the class object for class names written to the stream.
protected java.lang.Object	getReference(java.lang.String reference) Method which returns a previously stored reference.
protected java.lang.reflect.Constructor	getSerializableConstructor(java.lang.Class c) Method which returns the Serializable constructor for the provided class.
protected java.lang.Object	newInstance(java.lang.Class c) Method which returns a new instance of the provided class.
protected void	putReference(java.lang.String reference, java.lang.Object o) Method which adds a reference in the hashtable of references.
int	read() Method which reads a byte from the underlying output stream.
int	read(byte[] b, int offset, int length) Method which reads a array of bytes from the underlying output stream.
protected java.lang.Object	readArray(boolean shared) Method which reads an array off of the stream.
boolean	readBoolean() Method which reads a boolean from the stream and returns the result.
protected boolean	readBooleanHelper() Method which reads an boolean from the stream.
byte	readByte() Method which reads a byte from the stream and returns the result.
protected byte	readByteHelper() Method which reads an byte from the stream.
char	readChar() Method which reads a char from the stream and returns the result.
protected char	readCharHelper() Method which reads an char from the stream.
protected java.lang.Object	readClass(java.lang.Object o) Method which reads the information for one class for a given object from the stream.
double	readDouble() Method which reads a double from the stream and returns the result.
protected double	readDoubleHelper() Method which reads an double from the stream.
protected void	readField(java.lang.Object o, java.lang.Class c) Method which reads a single field from the stream, and assignes it to the provided object.
java.io.ObjectInputStream.GetField	readFields() Method which can be called by objects if they have a readObject() method.
protected void	readFields(java.lang.Object o, java.lang.Class c) Method which initiates the default field reading mechanism for the given object's class.
float	readFloat() Method which reads a float from the stream and returns the result.
protected float	readFloatHelper() Method which reads an float from the stream.
void	readFully(byte[] b) Method which reads a byte from the underlying output stream.
void	readFully(byte[] b, int offset, int length) Method which reads a byte from the underlying output stream.
protected void	readGetField(XMLObjectInputStream.GetField g) Method which read a single field from the stream and places it in the provided GetField object.
protected XMLObjectInputStream.GetField	readGetFields() Method which reads all of the field data from the stream, as readFields() does, but instead of assigning the fields to the object, it returns them as a GetField object.
int	readInt() Method which reads an int from the stream and returns the result.
protected int	readIntHelper() Method which reads an int from the stream.
long	readLong() Method which reads a long from the stream and returns the result.
protected long	readLongHelper() Method which reads an long from the stream.
protected java.lang.Object	readNull() Method which reads a null item off of the stream.
protected java.lang.Object	readObjectHelper() Method which reads an object from the stream.
protected java.lang.Object	readObjectOverride() Method which is called by ObjectInputStreamm.readObject(), and reads the next object from the stream, and returns the result.
protected java.lang.Object	readOrdinaryObject(boolean shared) Method which reads an ordinary object from the stream (not a String or Array).
protected java.lang.String	readPrimitive(java.lang.String type) Method which reads a primitive value from the stream and returns the String representation to the callee for processing.
protected void	readPrimitiveField(java.lang.Object o, java.lang.reflect.Field f) Method which reads a primitive field from the stream, and places it in the given object.
protected void	readPrimitiveGetField(XMLObjectInputStream.GetField g) Method which reads a primitive field from the stream, and places it in the provided GetField object.
protected java.lang.Object	readReference() Method which reads a reference off of the stream, and looks the reference up in the references table.
short	readShort() Method which reads a short from the stream and returns the result.
protected short	readShortHelper() Method which reads an short from the stream.
protected void	readStreamHeader() Method which reads the XML header off of the stream.
protected java.lang.Object	readString(boolean shared) Method which reads a string item off of the stream.
protected void	readUnreadOptionalData() Method which reads any extra data from the stream which was not read by the object.
java.lang.Object	readUnshared() Method which reads the next object from the stream and does not record a reference to the object.
protected java.lang.Object	readUnsharedHelper(boolean shared) Method which reads an object from the stream.
int	readUnsignedByte() Method which reads an unsigned byte from the underlying output stream.
int	readUnsignedShort() Method which reads an unsigned short from the underlying output stream.
java.lang.String	readUTF() Method which reads a UTF-encoded String from the stream and returns the result.
void	registerValidation(java.io.ObjectInputValidation obj, int prio) Register an object to be validated before the graph is returned.
void	reset() Method which resets the input stream, which removes the binding of all previously stored references.

Methods inherited from class java.io.ObjectInputStream

available, enableResolveObject, readClassDescriptor, readLine, readObject, resolveClass, resolveObject, resolveProxyClass, skipBytes

Methods inherited from class java.io.InputStream

mark, markSupported, read, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.io.ObjectInput

read, skip

Field Detail

READ_RESOLVES

protected static SoftHashMap READ_RESOLVES

The hashmap of readResolve methods, mapping Class->Method

READ_OBJECTS

protected static SoftHashMap READ_OBJECTS

The hashmap of readObject methods, mapping Class->Method

CONSTRUCTORS

protected static SoftHashMap CONSTRUCTORS

A cache of constructors, mapping classes to serialization constructors

reader

protected XMLReader reader

The underlying reader, which parses the XML

references

protected java.util.Hashtable references

The hashtable of references, which is updated each time a new object is read off of the stream.

currentObjects

protected java.util.Stack currentObjects

The stack of objects which are currently being read off of the stream

currentClasses

protected java.util.Stack currentClasses

The stack of class types which are being read off of the stream

reflFactory

protected sun.reflect.ReflectionFactory reflFactory

The ReflectionFactory, which allows for prividged construction of objects

vlist

protected rice.p2p.util.XMLObjectInputStream.ValidationList vlist

The list of validation objects waiting for the entire object graph to be read in

depth

protected int depth

The depth at which we are currently at in the object tree

Constructor Detail

XMLObjectInputStream

public XMLObjectInputStream(java.io.InputStream in)
                     throws java.io.IOException

Constructor which reads data from the given input stream in order deserialize objects. This constructor also reads the header from the stream, and throws an IOException if the correct header is not seen.

Parameters:

in - The input stream to read data from

Throws:

java.io.IOException - If the stream header is corrupt

Method Detail

readStreamHeader

protected void readStreamHeader()
                         throws java.io.IOException

Method which reads the XML header off of the stream. Usually, this is the tag, but it may include processing instructions.

Overrides:

readStreamHeader in class java.io.ObjectInputStream

Throws:

java.io.IOException - If the stream header is corrupt

close

public void close()
           throws java.io.IOException

Method which closes the underlying input stream for reading. Any subsequent reads will throw an IOException.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.io.ObjectInput

Overrides:

close in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

reset

public void reset()
           throws java.io.IOException

Method which resets the input stream, which removes the binding of all previously stored references.

Overrides:

reset in class java.io.InputStream

Throws:

java.io.IOException - If an error occurs

read

public int read()
         throws java.io.IOException

Method which reads a byte from the underlying output stream. Simply calls readByte()

Specified by:

read in interface java.io.ObjectInput

Overrides:

read in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

read

public int read(byte[] b,
                int offset,
                int length)
         throws java.io.IOException

Method which reads a array of bytes from the underlying output stream. Simply calls b[x] = readByte() on each of the array elements.

Specified by:

read in interface java.io.ObjectInput

Overrides:

read in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

readFully

public void readFully(byte[] b)
               throws java.io.IOException

Method which reads a byte from the underlying output stream. Simply calls read()

Specified by:

readFully in interface java.io.DataInput

Overrides:

readFully in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

readFully

public void readFully(byte[] b,
                      int offset,
                      int length)
               throws java.io.IOException

Method which reads a byte from the underlying output stream. Simply calls read()

Specified by:

readFully in interface java.io.DataInput

Overrides:

readFully in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

readUnsignedByte

public int readUnsignedByte()
                     throws java.io.IOException

Method which reads an unsigned byte from the underlying output stream. Simply calls readByte()

Specified by:

readUnsignedByte in interface java.io.DataInput

Overrides:

readUnsignedByte in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

readUnsignedShort

public int readUnsignedShort()
                      throws java.io.IOException

Method which reads an unsigned short from the underlying output stream. Simply calls readShort()

Specified by:

readUnsignedShort in interface java.io.DataInput

Overrides:

readUnsignedShort in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

readInt

public int readInt()
            throws java.io.IOException

Method which reads an int from the stream and returns the result.

Specified by:

readInt in interface java.io.DataInput

Overrides:

readInt in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readBoolean

public boolean readBoolean()
                    throws java.io.IOException

Method which reads a boolean from the stream and returns the result.

Specified by:

readBoolean in interface java.io.DataInput

Overrides:

readBoolean in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readByte

public byte readByte()
              throws java.io.IOException

Method which reads a byte from the stream and returns the result.

Specified by:

readByte in interface java.io.DataInput

Overrides:

readByte in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readChar

public char readChar()
              throws java.io.IOException

Method which reads a char from the stream and returns the result.

Specified by:

readChar in interface java.io.DataInput

Overrides:

readChar in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readDouble

public double readDouble()
                  throws java.io.IOException

Method which reads a double from the stream and returns the result.

Specified by:

readDouble in interface java.io.DataInput

Overrides:

readDouble in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readFloat

public float readFloat()
                throws java.io.IOException

Method which reads a float from the stream and returns the result.

Specified by:

readFloat in interface java.io.DataInput

Overrides:

readFloat in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readLong

public long readLong()
              throws java.io.IOException

Method which reads a long from the stream and returns the result.

Specified by:

readLong in interface java.io.DataInput

Overrides:

readLong in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readShort

public short readShort()
                throws java.io.IOException

Method which reads a short from the stream and returns the result.

Specified by:

readShort in interface java.io.DataInput

Overrides:

readShort in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readUTF

public java.lang.String readUTF()
                         throws java.io.IOException

Method which reads a UTF-encoded String from the stream and returns the result. This method simply calls readObject(), as all strings are UTF encoded in XML.

Specified by:

readUTF in interface java.io.DataInput

Overrides:

readUTF in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

readObjectOverride

protected java.lang.Object readObjectOverride()
                                       throws java.io.IOException,
                                              java.lang.ClassNotFoundException

Method which is called by ObjectInputStreamm.readObject(), and reads the next object from the stream, and returns the result. If the object (or any of it's descendents) has a readResolve() method, that object is returned.

Overrides:

readObjectOverride in class java.io.ObjectInputStream

Returns:

The value from the stream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If a class in the stream cannot be found

readUnshared

public java.lang.Object readUnshared()
                              throws java.io.IOException,
                                     java.lang.ClassNotFoundException

Method which reads the next object from the stream and does not record a reference to the object. This guarantees that in future references to this object in the stream will throw an IOException.

Overrides:

readUnshared in class java.io.ObjectInputStream

Returns:

The next object from the stream, without recording a reference

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If a class in the stream cannot be found

defaultReadObject

public void defaultReadObject()
                       throws java.io.IOException,
                              java.lang.ClassNotFoundException

Method which can be called by objects if they have a readObject() method. This method initiates the default field deserialization mechanism, and sets all of the object's fields from the stream. If this method is called, the readFields() method CANNOT be called by the same object. However, one of these two methods MUST be called in the context of a readObject().

Overrides:

defaultReadObject in class java.io.ObjectInputStream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If a class in the stream cannot be found

java.io.NotActiveException - If a object is not currently being read

readFields

public java.io.ObjectInputStream.GetField readFields()
                                              throws java.io.IOException,
                                                     java.lang.ClassNotFoundException

Method which can be called by objects if they have a readObject() method. This method initiates the default field deserialization mechanism, and reads all of the default fields in the stream. It does NOT set the field values of the object, however, but instead returns the result to the Object as a GetField object. It is explicitly the responsibility of the object to set its fields appropriately. If this method is called, the defaultReadObject() method CANNOT be called by the same object. However, one of these two methods MUST be called in the context of a readObject().

Overrides:

readFields in class java.io.ObjectInputStream

Returns:

A GetField, representing all of this object's fields

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If a class in the stream cannot be found

java.io.NotActiveException - If a object is not currently being read

registerValidation

public void registerValidation(java.io.ObjectInputValidation obj,
                               int prio)
                        throws java.io.NotActiveException,
                               java.io.InvalidObjectException

Register an object to be validated before the graph is returned. While similar to resolveObject these validations are called after the entire graph has been reconstituted. Typically, a readObject method will register the object with the stream so that when all of the objects are restored a final set of validations can be performed.

Overrides:

registerValidation in class java.io.ObjectInputStream

Parameters:

obj - the object to receive the validation callback.

prio - controls the order of callbacks

Throws:

java.io.NotActiveException - The stream is not currently reading objects so it is invalid to register a callback.

java.io.InvalidObjectException - The validation object is null.

getSerializableConstructor

protected java.lang.reflect.Constructor getSerializableConstructor(java.lang.Class c)
                                                            throws java.io.IOException,
                                                                   java.lang.NoSuchMethodException

Method which returns the Serializable constructor for the provided class. This Constructor is the no-arg Constructor for the first non-Serializable class in the class's superclass heirarchy. This method does not cache the result, but does set the constructor to be accessible, regardless of the Java security protection.

Parameters:

c - The class to fetch the constructor for

Throws:

java.io.IOException - If an error occurs

java.lang.NoSuchMethodException - If the first non-Serializable class does not have a no-arg Constructor

newInstance

protected java.lang.Object newInstance(java.lang.Class c)
                                throws java.io.IOException

Method which returns a new instance of the provided class. It does this by getting the class's serializable constructor (described in getSerializableConstructor()) and using it to create a new object. Thus, all of the Serializable superclasses of the object must be initialized from the stream.

Parameters:

c - The class to create a new instance of

Throws:

java.io.IOException - If an error occurs

getClass

protected java.lang.Class getClass(java.lang.String name)
                            throws java.lang.ClassNotFoundException

Method which returns the class object for class names written to the stream. If the name represents a primitive, the the X.TYPE class is returned, otherwise, Class.forName() is used.

Parameters:

name - The name of the class to return

Throws:

java.lang.ClassNotFoundException - If the class cannot be found

putReference

protected void putReference(java.lang.String reference,
                            java.lang.Object o)

Method which adds a reference in the hashtable of references. Multiple calls to this method will replace prior objects.

Parameters:

reference - The reference name to use

o - The object to reference

getReference

protected java.lang.Object getReference(java.lang.String reference)

Method which returns a previously stored reference. If the reference cannot be found, null is returned.

Parameters:

reference - The reference to use

Returns:

The referenced object, or null if none can be found

readPrimitive

protected java.lang.String readPrimitive(java.lang.String type)
                                  throws java.io.IOException

Method which reads a primitive value from the stream and returns the String representation to the callee for processing. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The String representation of the primitive

Throws:

java.io.IOException - If an error occurs

readIntHelper

protected int readIntHelper()
                     throws java.io.IOException

Method which reads an int from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The int read from the stream

Throws:

java.io.IOException - If an error occurs

readBooleanHelper

protected boolean readBooleanHelper()
                             throws java.io.IOException

Method which reads an boolean from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The boolean read from the stream

Throws:

java.io.IOException - If an error occurs

readByteHelper

protected byte readByteHelper()
                       throws java.io.IOException

Method which reads an byte from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The byte read from the stream

Throws:

java.io.IOException - If an error occurs

readCharHelper

protected char readCharHelper()
                       throws java.io.IOException

Method which reads an char from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The char read from the stream

Throws:

java.io.IOException - If an error occurs

readDoubleHelper

protected double readDoubleHelper()
                           throws java.io.IOException

Method which reads an double from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The double read from the stream

Throws:

java.io.IOException - If an error occurs

readFloatHelper

protected float readFloatHelper()
                         throws java.io.IOException

Method which reads an float from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The float read from the stream

Throws:

java.io.IOException - If an error occurs

readLongHelper

protected long readLongHelper()
                       throws java.io.IOException

Method which reads an long from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The long read from the stream

Throws:

java.io.IOException - If an error occurs

readShortHelper

protected short readShortHelper()
                         throws java.io.IOException

Method which reads an short from the stream. This method assumes that the XML reader is currently on a primitive tag, and does consume the end primitive tag.

Parameters:

type - The type of primitive which should be next

Returns:

The short read from the stream

Throws:

java.io.IOException - If an error occurs

readObjectHelper

protected java.lang.Object readObjectHelper()
                                     throws java.io.IOException,
                                            java.lang.ClassNotFoundException

Method which reads an object from the stream. This method assumes that the XML reader is currently on a start tag, and does consume the corresponding end tag. If the next object represents a reference or null, then the appropriate helper is called. Otherwise, readObjectUnshared() is called to process the object.

Returns:

The object read from the stream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readUnsharedHelper

protected java.lang.Object readUnsharedHelper(boolean shared)
                                       throws java.io.IOException,
                                              java.lang.ClassNotFoundException

Method which reads an object from the stream. This method assumes that the XML reader is currently on a start tag, and does consume the corresponding end tag. This method also assumes that the type of object which is being read is *sharable*, even if it is not going to be shared. Thus, this method can read objects of type String, Array, or Serializable.

Parameters:

shared - Whether or not to record a reference to this object

Returns:

The object read from the stream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readReference

protected java.lang.Object readReference()
                                  throws java.io.IOException,
                                         java.lang.ClassNotFoundException

Method which reads a reference off of the stream, and looks the reference up in the references table. If not corresponding object is found, an IOException is thrown. This method expected that a reference tag has just been read, and it does consume the end reference tag.

Throws:

java.io.IOException - If an error occurs or if a reference is not found

java.lang.ClassNotFoundException - If the class cannot be found

readNull

protected java.lang.Object readNull()
                             throws java.io.IOException,
                                    java.lang.ClassNotFoundException

Method which reads a null item off of the stream. This method expected that a null tag has just been read, and it does consume the end null tag.

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readString

protected java.lang.Object readString(boolean shared)
                               throws java.io.IOException,
                                      java.lang.ClassNotFoundException

Method which reads a string item off of the stream. This method expects that a start string tag has just been read, an it does consume the end start tag. If this string is to be shared, a reference is added to the references tag.

Parameters:

shared - Whether or not to add this string to the references table

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readOrdinaryObject

protected java.lang.Object readOrdinaryObject(boolean shared)
                                       throws java.io.IOException,
                                              java.lang.ClassNotFoundException

Method which reads an ordinary object from the stream (not a String or Array). This method assumes that the XML reader is currently on a start tag, and does consume the corresponding end tag. This method first reads the class type, and if it is Serializable, it constructs a new instance. Then, if the object is shared and the id field is not null, it records a reference to the object. If the object is Externalizable, the readExternal() method is called and the object is returned. Otherwise, each of the superclasses are read, from highest to lowest, using the readClass() method. Lastly, if the object defines a readResolve() method, it is called and the result is recorded and returned.

Parameters:

shared - Whether or not to record a reference to this object

Returns:

The object read from the stream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

java.io.NotSerializableException - If the class to be deserialized is not Serializable

readClass

protected java.lang.Object readClass(java.lang.Object o)
                              throws java.io.IOException,
                                     java.lang.ClassNotFoundException

Method which reads the information for one class for a given object from the stream. This method assumes that the XML reader is currently on a start declaredClass tag, and does consume the corresponding end declaredClass tag. This method first reads the class type, and if it defines a readObject() method, it is called. Otherwise, the fields are read in a default manner. Any extra data not read in the stream is read and ignored.

Parameters:

o - The object we are reading the the class for

Returns:

The object read from the stream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readUnreadOptionalData

protected void readUnreadOptionalData()
                               throws java.io.IOException,
                                      java.lang.ClassNotFoundException

Method which reads any extra data from the stream which was not read by the object. This method simply loops until it hits the appropriate end declaredClass tag, and then returns. Thus, any data read by this method is ignored. However, the objects here are deserialized as the stream may reference them in the future.

Parameters:

o - The object we are reading the the class for

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readGetFields

protected XMLObjectInputStream.GetField readGetFields()
                                               throws java.io.IOException,
                                                      java.lang.ClassNotFoundException

Method which reads all of the field data from the stream, as readFields() does, but instead of assigning the fields to the object, it returns them as a GetField object. In this manner, the object itself can perform field inititalization.

Returns:

The fields read from the stream

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readGetField

protected void readGetField(XMLObjectInputStream.GetField g)
                     throws java.io.IOException,
                            java.lang.ClassNotFoundException

Method which read a single field from the stream and places it in the provided GetField object. This method assumes that the XML reader is on a start tag, and that the item read has a field attribute.

Parameters:

g - The GetField object into which the field should be put

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readPrimitiveGetField

protected void readPrimitiveGetField(XMLObjectInputStream.GetField g)
                              throws java.io.IOException,
                                     java.lang.ClassNotFoundException

Method which reads a primitive field from the stream, and places it in the provided GetField object. This method assumes that the XML parser has just read a primitive start tag, and that the tag has a field attribute. This method does consume that end primitive tag.

Parameters:

g - The GetField object to put the primitive in

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException

readFields

protected void readFields(java.lang.Object o,
                          java.lang.Class c)
                   throws java.io.IOException,
                          java.lang.ClassNotFoundException

Method which initiates the default field reading mechanism for the given object's class. This method reads the start default tag, all of the fields, and then reads the end default tag. It reads all of the fields using the readField() method.

Parameters:

o - The object which is currently being read in

c - The class to read the fields for

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readField

protected void readField(java.lang.Object o,
                         java.lang.Class c)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Method which reads a single field from the stream, and assignes it to the provided object. If the field cannot be found in the given class, it is deserialized and then ignored, in case it is referenced later in the stream.

Parameters:

o - The object which is currently being read in

c - The class to read the fields for

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found

readPrimitiveField

protected void readPrimitiveField(java.lang.Object o,
                                  java.lang.reflect.Field f)
                           throws java.io.IOException,
                                  java.lang.IllegalAccessException

Method which reads a primitive field from the stream, and places it in the given object. This method assumes that the XML parser has just read a primitive start tag, and that the tag has a field attribute. This method does consume that end primitive tag.

Parameters:

o - The object to put the primitive in

f - The field representing the primitive about to be read

Throws:

java.io.IOException - If an error occurs

java.lang.IllegalAccessException

readArray

protected java.lang.Object readArray(boolean shared)
                              throws java.io.IOException,
                                     java.lang.ClassNotFoundException

Method which reads an array off of the stream. This method expects that a start array tag has just been read, and does consume the end array tag. This method constructs an array of the provided base type, and then recursively reads in all of the objects for the array.

Parameters:

shared - Whether or not to add this array to the references table

Throws:

java.io.IOException - If an error occurs

java.lang.ClassNotFoundException - If the class cannot be found