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com.tangosol.io
Class WrapperDataInputStream

java.lang.Object
java.io.InputStream
com.tangosol.io.WrapperDataInputStream

All Implemented Interfaces:

InputStreaming, Closeable, DataInput

Direct Known Subclasses:

WrapperObjectInputStream

public class WrapperDataInputStream

extends InputStream

implements DataInput, InputStreaming

This is an imitation DataInputStream class that provides the DataInput interface by delegating to an object that implements the DataInput interface. Primarily, this is intended as a base class for building specific-purpose DataInput wrappers.

Author:

cp 2004.09.09

Constructor Summary

WrapperDataInputStream(DataInput in)
Construct a WrapperDataInputStream that will read from the specified object implementing the DataInput interface.

Method Summary

int	available() Returns the number of bytes that can be read (or skipped over) from this input stream without causing a blocking I/O condition to occur.
void	close() Close the InputStream and release any system resources associated with it.
DataInput	getDataInput() Obtain the underlying object providing the DataInput interface that this object is delegating to.
void	mark(int cbReadLimit) Marks the current read position in the InputStream in order to support the stream to be later "rewound" (using the reset() method) to the current position.
boolean	markSupported() Determine if this InputStream supports the mark(int) and reset() methods.
int	read() Read the next byte of data from the InputStream.
int	read(byte[] ab) Read some number of bytes from the input stream and store them into the passed array ab.
int	read(byte[] ab, int of, int cb) Read up to cb bytes from the input stream and store them into the passed array ab starting at offset of.
boolean	readBoolean() Read a boolean value.
byte	readByte() Read a byte value.
char	readChar() Read a char value.
double	readDouble() Read a double value.
float	readFloat() Read a float value.
void	readFully(byte[] ab) Read ab.length bytes and store them in ab.
void	readFully(byte[] ab, int of, int cb) Read cb bytes and store them in ab starting at offset of.
int	readInt() Read an int value.
String	readLine() Reads the next "line" of text.
long	readLong() Read a long value.
short	readShort() Read a short value.
int	readUnsignedByte() Read an unsigned byte value.
int	readUnsignedShort() Read an unsigned short value.
String	readUTF() Reads a String value.
void	reset() Rewind this stream to the position at the time the mark(int) method was last called on this InputStream.
long	skip(long cb) Skips over up to the specified number of bytes of data from this InputStream.
int	skipBytes(int cb) Skips over up to the specified number of bytes of data.

Constructor Detail

WrapperDataInputStream

public WrapperDataInputStream(DataInput in)

Construct a WrapperDataInputStream that will read from the specified object implementing the DataInput interface.

Parameters:

in - an object implementing DataInput to read from

Method Detail

getDataInput

public DataInput getDataInput()

Obtain the underlying object providing the DataInput interface that this object is delegating to.

Returns:

the underlying DataInput

readFully

public void readFully(byte[] ab)
               throws IOException

Read ab.length bytes and store them in ab.

This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Specified by:

readFully in interface DataInput

Parameters:

ab - the array to store the bytes which are read from the stream

Throws:

NullPointerException - if the passed array is null

EOFException - if the stream is exhausted before the number of bytes indicated by the array length could be read

IOException - if an I/O error occurs

readFully

public void readFully(byte[] ab,
                      int of,
                      int cb)
               throws IOException

Read cb bytes and store them in ab starting at offset of.

This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Specified by:

readFully in interface DataInput

Parameters:

ab - the array to store the bytes which are read from the stream

of - the offset into the array that the read bytes will be stored

cb - the maximum number of bytes to read

Throws:

NullPointerException - if the passed array is null

IndexOutOfBoundsException - if of or cb is negative, or of+cb is greater than the length of the ab

EOFException - if the stream is exhausted before the number of bytes indicated by the array length could be read

IOException - if an I/O error occurs

skipBytes

public int skipBytes(int cb)
              throws IOException

Skips over up to the specified number of bytes of data. The number of bytes actually skipped over may be fewer than the number specified to skip, and may even be zero; this can be caused by an end-of-file condition, but can also occur even when there is data remaining to be read. As a result, the caller should check the return value from this method, which indicates the actual number of bytes skipped.

Specified by:

skipBytes in interface DataInput

Parameters:

cb - the maximum number of bytes to skip over

Returns:

the actual number of bytes that were skipped over

Throws:

IOException - if an I/O error occurs

readBoolean

public boolean readBoolean()
                    throws IOException

Read a boolean value.

This method is the counterpart for the DataOutput.writeBoolean(boolean) method.

Specified by:

readBoolean in interface DataInput

Returns:

either true or false

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readByte

public byte readByte()
              throws IOException

Read a byte value.

This method is the counterpart for the DataOutput.writeByte(int) method.

Specified by:

readByte in interface DataInput

Returns:

a byte value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readUnsignedByte

public int readUnsignedByte()
                     throws IOException

Read an unsigned byte value.

This method is the counterpart for the DataOutput.writeByte(int) method when it is used with unsigned 8-bit values.

Specified by:

readUnsignedByte in interface DataInput

Returns:

an int value in the range 0x00 to 0xFF

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readShort

public short readShort()
                throws IOException

Read a short value.

This method is the counterpart for the DataOutput.writeShort(int) method.

Specified by:

readShort in interface DataInput

Returns:

a short value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readUnsignedShort

public int readUnsignedShort()
                      throws IOException

Read an unsigned short value.

This method is the counterpart for the DataOutput.writeShort(int) method when it is used with unsigned 16-bit values.

Specified by:

readUnsignedShort in interface DataInput

Returns:

an int value in the range of 0x0000 to 0xFFFF

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readChar

public char readChar()
              throws IOException

Read a char value.

This method is the counterpart for the DataOutput.writeChar(int) method.

Specified by:

readChar in interface DataInput

Returns:

a char value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readInt

public int readInt()
            throws IOException

Read an int value.

This method is the counterpart for the DataOutput.writeInt(int) method.

Specified by:

readInt in interface DataInput

Returns:

an int value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readLong

public long readLong()
              throws IOException

Read a long value.

This method is the counterpart for the DataOutput.writeLong(long) method.

Specified by:

readLong in interface DataInput

Returns:

a long value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readFloat

public float readFloat()
                throws IOException

Read a float value.

This method is the counterpart for the DataOutput.writeFloat(float) method.

Specified by:

readFloat in interface DataInput

Returns:

a float value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readDouble

public double readDouble()
                  throws IOException

Read a double value.

This method is the counterpart for the DataOutput.writeDouble(double) method.

Specified by:

readDouble in interface DataInput

Returns:

a double value

Throws:

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

readLine

public String readLine()
                throws IOException

Reads the next "line" of text.

This method does not have a counterpart in the DataOutput interface. Furthermore, this method is defined as operating on bytes and not on characters, and thus it should be selected for use only after careful consideration, as if it were deprecated.

Specified by:

readLine in interface DataInput

Returns:

a line of text as a String

Throws:

IOException - if an I/O error occurs.

readUTF

public String readUTF()
               throws IOException

Reads a String value.

This method is the counterpart for the DataOutput.writeUTF(java.lang.String) method.

Specified by:

readUTF in interface DataInput

Returns:

a String value

Throws:

UTFDataFormatException - if the bytes that were read were not a valid UTF-8 encoded string

EOFException - if the value could not be read because no more data remains to be read

IOException - if an I/O error occurs

read

public int read()
         throws IOException

Read the next byte of data from the InputStream. The value byte is returned as an int in the range 0 to 255. If the end of the stream has been reached, the value -1 is returned.

This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Specified by:

read in interface InputStreaming

Specified by:

read in class InputStream

Returns:

the next byte of data, or -1 if the end of the stream has been reached

Throws:

IOException - if an I/O error occurs

read

public int read(byte[] ab)
         throws IOException

Read some number of bytes from the input stream and store them into the passed array ab. The number of bytes actually read is returned.

This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Specified by:

read in interface InputStreaming

Overrides:

read in class InputStream

Parameters:

ab - the array to store the bytes which are read from the stream

Returns:

the number of bytes read from the stream, or -1 if no bytes were read from the stream because the end of the stream had been reached

Throws:

NullPointerException - if the passed array is null

IOException - if an I/O error occurs

read

public int read(byte[] ab,
                int of,
                int cb)
         throws IOException

Read up to cb bytes from the input stream and store them into the passed array ab starting at offset of. The number of bytes actually read is returned.

This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Specified by:

read in interface InputStreaming

Overrides:

read in class InputStream

Parameters:

ab - the array to store the bytes which are read from the stream

of - the offset into the array that the read bytes will be stored

cb - the maximum number of bytes to read

Returns:

the number of bytes read from the stream, or -1 if no bytes were read from the stream because the end of the stream had been reached

Throws:

NullPointerException - if the passed array is null

IndexOutOfBoundsException - if of or cb is negative, or of+cb is greater than the length of the ab

IOException - if an I/O error occurs

skip

public long skip(long cb)
          throws IOException

Skips over up to the specified number of bytes of data from this InputStream. The number of bytes actually skipped over may be fewer than the number specified to skip, and may even be zero; this can be caused by an end-of-file condition, but can also occur even when there is data remaining in the InputStream. As a result, the caller should check the return value from this method, which indicates the actual number of bytes skipped.

Specified by:

skip in interface InputStreaming

Overrides:

skip in class InputStream

Parameters:

cb - the maximum number of bytes to skip over

Returns:

the actual number of bytes that were skipped over

Throws:

IOException - if an I/O error occurs

available

public int available()
              throws IOException

Returns the number of bytes that can be read (or skipped over) from this input stream without causing a blocking I/O condition to occur. This method reflects the assumed implementation of various buffering InputStreams, which can guarantee non-blocking reads up to the extent of their buffers, but beyond that the read operations will have to read from some underlying (and potentially blocking) source.

Specified by:

available in interface InputStreaming

Overrides:

available in class InputStream

Returns:

the number of bytes that can be read from this InputStream without blocking

Throws:

IOException - if an I/O error occurs

close

public void close()
           throws IOException

Close the InputStream and release any system resources associated with it.

Specified by:

close in interface InputStreaming

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException - if an I/O error occurs

mark

public void mark(int cbReadLimit)

Marks the current read position in the InputStream in order to support the stream to be later "rewound" (using the reset() method) to the current position. The caller passes in the maximum number of bytes that it expects to read before calling the reset() method, thus indicating the upper bounds of the responsibility of the stream to be able to buffer what it has read in order to support this functionality.

Specified by:

mark in interface InputStreaming

Overrides:

mark in class InputStream

Parameters:

cbReadLimit - the maximum number of bytes that caller expects the InputStream to be able to read before the mark position becomes invalid

reset

public void reset()
           throws IOException

Rewind this stream to the position at the time the mark(int) method was last called on this InputStream. If the InputStream cannot fulfill this contract, it should throw an IOException.

Specified by:

reset in interface InputStreaming

Overrides:

reset in class InputStream

Throws:

IOException - if an I/O error occurs, for example if this has not been marked or if the mark has been invalidated

markSupported

public boolean markSupported()

Determine if this InputStream supports the mark(int) and reset() methods.

Specified by:

markSupported in interface InputStreaming

Overrides:

markSupported in class InputStream

Returns:

true if this InputStream supports the mark and reset method; false otherwise

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