org.jboss.marshalling
Class AbstractUnmarshaller

java.lang.Object
  org.jboss.marshalling.AbstractUnmarshaller

All Implemented Interfaces:

Closeable, DataInput, ObjectInput, ByteInput, Unmarshaller

public abstract class AbstractUnmarshaller
extends Object
implements Unmarshaller

An abstract implementation of the Unmarshaller interface. Most of the write methods delegate directly to the current data output.

Field Summary

protected ByteInput	byteInput The current byte input.
protected ClassResolver	classResolver The configured class resolver.
protected ClassTable	classTable The configured class table.
protected Creator	creator The configured object creator.
protected ExternalizerFactory	externalizerFactory The configured externalizer factory.
protected ObjectResolver	objectResolver The configured object resolver.
protected ObjectTable	objectTable The configured object table.
protected StreamHeader	streamHeader The configured stream header.

Constructor Summary

protected

AbstractUnmarshaller(AbstractMarshallerFactory marshallerFactory, MarshallingConfiguration configuration) Construct a new unmarshaller instance.

Method Summary

int	available() Returns the number of bytes that can be read without blocking.
protected abstract Object	doReadObject(boolean unshared) Implementation of the actual object-reading method.
protected void	doStart() Perform any unmarshaller-specific start activity.
void	finish() Finish unmarshalling from a stream.
int	read() Reads a byte of data.
int	read(byte[] b) Reads into an array of bytes.
int	read(byte[] b, int off, int len) Reads into an array of bytes.
boolean	readBoolean() Reads one input byte and returns true if that byte is nonzero, false if that byte is zero.
byte	readByte() Reads and returns one input byte.
char	readChar() Reads two input bytes and returns a char value.
double	readDouble() Reads eight input bytes and returns a double value.
float	readFloat() Reads four input bytes and returns a float value.
void	readFully(byte[] b) Reads some bytes from an input stream and stores them into the buffer array b.
void	readFully(byte[] b, int off, int len) Reads len bytes from an input stream.
int	readInt() Reads four input bytes and returns an int value.
String	readLine() Reads the next line of text from the input stream.
long	readLong() Reads eight input bytes and returns a long value.
Object	readObject() Read and return an object.
Object	readObjectUnshared() Read and return an unshared object.
short	readShort() Reads two input bytes and returns a short value.
int	readUnsignedByte() Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255.
int	readUnsignedShort() Reads two input bytes and returns an int value in the range 0 through 65535.
String	readUTF() Reads in a string that has been encoded using a modified UTF-8 format.
long	skip(long n) Skips n bytes of input.
int	skipBytes(int n) Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes.
void	start(ByteInput byteInput) Begin unmarshalling from a stream.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jboss.marshalling.Unmarshaller

clearClassCache, clearInstanceCache

Methods inherited from interface java.io.ObjectInput

close

Methods inherited from interface java.io.Closeable

close

Field Detail

externalizerFactory

protected final ExternalizerFactory externalizerFactory

The configured externalizer factory.

streamHeader

protected final StreamHeader streamHeader

The configured stream header.

classResolver

protected final ClassResolver classResolver

The configured class resolver.

objectResolver

protected final ObjectResolver objectResolver

The configured object resolver.

creator

protected final Creator creator

The configured object creator.

classTable

protected final ClassTable classTable

The configured class table.

objectTable

protected final ObjectTable objectTable

The configured object table.

byteInput

protected ByteInput byteInput

The current byte input.

Constructor Detail

AbstractUnmarshaller

protected AbstractUnmarshaller(AbstractMarshallerFactory marshallerFactory,
                               MarshallingConfiguration configuration)

Construct a new unmarshaller instance.

Parameters:

marshallerFactory - the marshaller factory

configuration -

Method Detail

readObject

public final Object readObject()
                        throws ClassNotFoundException,
                               IOException

Read and return an object. The class that implements this interface defines where the object is "read" from.

Specified by:

readObject in interface ObjectInput

Returns:

the object read from the stream

Throws:

ClassNotFoundException - If the class of a serialized object cannot be found.

IOException - If any of the usual Input/Output related exceptions occur.

readObjectUnshared

public final Object readObjectUnshared()
                                throws ClassNotFoundException,
                                       IOException

Read and return an unshared object.

Specified by:

readObjectUnshared in interface Unmarshaller

Returns:

an unshared object

Throws:

IOException - if an error occurs

ClassNotFoundException

doReadObject

protected abstract Object doReadObject(boolean unshared)
                                throws ClassNotFoundException,
                                       IOException

Implementation of the actual object-reading method.

Parameters:

unshared - true if the instance should be unshared, false if it is shared

Returns:

the object to read

Throws:

ClassNotFoundException - if the class for the object could not be loaded

IOException - if an I/O error occurs

read

public int read()
         throws IOException

Reads a byte of data. This method will block if no input is available.

Specified by:

read in interface ObjectInput

Specified by:

read in interface ByteInput

Returns:

the byte read, or -1 if the end of the stream is reached.

Throws:

IOException - If an I/O error has occurred.

read

public int read(byte[] b)
         throws IOException

Reads into an array of bytes. This method will block until some input is available.

Specified by:

read in interface ObjectInput

Specified by:

read in interface ByteInput

Parameters:

b - the buffer into which the data is read

Returns:

the actual number of bytes read, -1 is returned when the end of the stream is reached.

Throws:

IOException - If an I/O error has occurred.

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Reads into an array of bytes. This method will block until some input is available.

Specified by:

read in interface ObjectInput

Specified by:

read in interface ByteInput

Parameters:

b - the buffer into which the data is read

off - the start offset of the data

len - the maximum number of bytes read

Returns:

the actual number of bytes read, -1 is returned when the end of the stream is reached.

Throws:

IOException - If an I/O error has occurred.

skip

public long skip(long n)
          throws IOException

Skips n bytes of input.

Specified by:

skip in interface ObjectInput

Specified by:

skip in interface ByteInput

Parameters:

n - the number of bytes to be skipped

Returns:

the actual number of bytes skipped.

Throws:

IOException - If an I/O error has occurred.

available

public int available()
              throws IOException

Returns the number of bytes that can be read without blocking.

Specified by:

available in interface ObjectInput

Specified by:

available in interface ByteInput

Returns:

the number of available bytes.

Throws:

IOException - If an I/O error has occurred.

readFully

public void readFully(byte[] b)
               throws IOException

Reads some bytes from an input stream and stores them into the buffer array b. The number of bytes read is equal to the length of b.

This method blocks until one of the following conditions occurs:

• b.length bytes of input data are available, in which case a normal return is made.
• End of file is detected, in which case an EOFException is thrown.
• An I/O error occurs, in which case an IOException other than EOFException is thrown.

If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[0], the next one into b[1], and so on. If an exception is thrown from this method, then it may be that some but not all bytes of b have been updated with data from the input stream.

Specified by:

readFully in interface DataInput

Parameters:

b - the buffer into which the data is read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readFully

public void readFully(byte[] b,
                      int off,
                      int len)
               throws IOException

Reads len bytes from an input stream.

This method blocks until one of the following conditions occurs:

• len bytes of input data are available, in which case a normal return is made.
• End of file is detected, in which case an EOFException is thrown.
• An I/O error occurs, in which case an IOException other than EOFException is thrown.

If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len.

Specified by:

readFully in interface DataInput

Parameters:

b - the buffer into which the data is read.

off - an int specifying the offset into the data.

len - an int specifying the number of bytes to read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

skipBytes

public int skipBytes(int n)
              throws IOException

Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned.

Specified by:

skipBytes in interface DataInput

Parameters:

n - the number of bytes to be skipped.

Returns:

the number of bytes actually skipped.

Throws:

IOException - if an I/O error occurs.

readBoolean

public boolean readBoolean()
                    throws IOException

Reads one input byte and returns true if that byte is nonzero, false if that byte is zero. This method is suitable for reading the byte written by the writeBoolean method of interface DataOutput.

Specified by:

readBoolean in interface DataInput

Returns:

the boolean value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readByte

public byte readByte()
              throws IOException

Reads and returns one input byte. The byte is treated as a signed value in the range -128 through 127, inclusive. This method is suitable for reading the byte written by the writeByte method of interface DataOutput.

Specified by:

readByte in interface DataInput

Returns:

the 8-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readUnsignedByte

public int readUnsignedByte()
                     throws IOException

Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface DataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.

Specified by:

readUnsignedByte in interface DataInput

Returns:

the unsigned 8-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readShort

public short readShort()
                throws IOException

Reads two input bytes and returns a short value. Let a be the first byte read and b be the second byte. The value returned is:

(short)((a << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface DataOutput.

Specified by:

readShort in interface DataInput

Returns:

the 16-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readUnsignedShort

public int readUnsignedShort()
                      throws IOException

Reads two input bytes and returns an int value in the range 0 through 65535. Let a be the first byte read and b be the second byte. The value returned is:

(((a & 0xff) << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface DataOutput if the argument to writeShort was intended to be a value in the range 0 through 65535.

Specified by:

readUnsignedShort in interface DataInput

Returns:

the unsigned 16-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readChar

public char readChar()
              throws IOException

Reads two input bytes and returns a char value. Let a be the first byte read and b be the second byte. The value returned is:

(char)((a << 8) | (b & 0xff))
 

This method is suitable for reading bytes written by the writeChar method of interface DataOutput.

Specified by:

readChar in interface DataInput

Returns:

the char value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readInt

public int readInt()
            throws IOException

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read. The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) |
  ((c & 0xff) << 8) | (d & 0xff))
 

This method is suitable for reading bytes written by the writeInt method of interface DataOutput.

Specified by:

readInt in interface DataInput

Returns:

the int value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readLong

public long readLong()
              throws IOException

Reads eight input bytes and returns a long value. Let a-h be the first through eighth bytes read. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16) |
  ((long)(g & 0xff) <<  8) |
  ((long)(h & 0xff)))
 

This method is suitable for reading bytes written by the writeLong method of interface DataOutput.

Specified by:

readLong in interface DataInput

Returns:

the long value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readFloat

public float readFloat()
                throws IOException

Reads four input bytes and returns a float value. It does this by first constructing an int value in exactly the manner of the readInt method, then converting this int value to a float in exactly the manner of the method Float.intBitsToFloat. This method is suitable for reading bytes written by the writeFloat method of interface DataOutput.

Specified by:

readFloat in interface DataInput

Returns:

the float value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readDouble

public double readDouble()
                  throws IOException

Reads eight input bytes and returns a double value. It does this by first constructing a long value in exactly the manner of the readlong method, then converting this long value to a double in exactly the manner of the method Double.longBitsToDouble. This method is suitable for reading bytes written by the writeDouble method of interface DataOutput.

Specified by:

readDouble in interface DataInput

Returns:

the double value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readLine

public String readLine()
                throws IOException

Reads the next line of text from the input stream. It reads successive bytes, converting each byte separately into a character, until it encounters a line terminator or end of file; the characters read are then returned as a String. Note that because this method processes bytes, it does not support input of the full Unicode character set.

If end of file is encountered before even one byte can be read, then null is returned. Otherwise, each byte that is read is converted to type char by zero-extension. If the character '\n' is encountered, it is discarded and reading ceases. If the character '\r' is encountered, it is discarded and, if the following byte converts to the character '\n', then that is discarded also; reading then ceases. If end of file is encountered before either of the characters '\n' and '\r' is encountered, reading ceases. Once reading has ceased, a String is returned that contains all the characters read and not discarded, taken in order. Note that every character in this string will have a value less than \u0100, that is, (char)256.

Specified by:

readLine in interface DataInput

Returns:

the next line of text from the input stream, or null if the end of file is encountered before a byte can be read.

Throws:

IOException - if an I/O error occurs.

readUTF

public String readUTF()
               throws IOException

Reads in a string that has been encoded using a modified UTF-8 format. The general contract of readUTF is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.

First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the readUnsignedShort method . This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.

If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.

If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:

(char)(((a& 0x1F) << 6) | (b & 0x3F))
 

If the first byte of a group matches the bit pattern 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:

 (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
 

If the first byte of a group matches the pattern 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown.

If end of file is encountered at any time during this entire process, then an EOFException is thrown.

After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.

The writeUTF method of interface DataOutput may be used to write data that is suitable for reading by this method.

Specified by:

readUTF in interface DataInput

Returns:

a Unicode string.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

UTFDataFormatException - if the bytes do not represent a valid modified UTF-8 encoding of a string.

start

public void start(ByteInput byteInput)
           throws IOException

Begin unmarshalling from a stream.

Specified by:

start in interface Unmarshaller

Parameters:

byteInput - the new stream

Throws:

IOException - if an error occurs during setup, such as an invalid header

finish

public void finish()
            throws IOException

Finish unmarshalling from a stream. Any transient class or instance cache is discarded.

Specified by:

finish in interface Unmarshaller

Throws:

IOException - if an error occurs

doStart

protected void doStart()
                throws IOException

Perform any unmarshaller-specific start activity. This implementation simply reads the stream header.

Throws:

IOException - if I/O exception occurs