org.apache.derby.client.am
Class ClobLocatorInputStream

java.lang.Object
  java.io.InputStream
      org.apache.derby.client.am.ClobLocatorInputStream

All Implemented Interfaces:

java.io.Closeable

public class ClobLocatorInputStream
extends java.io.InputStream

An InputStream that will use an locator to fetch the Clob value from the server.

Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

This InputStream implementation is pretty basic. No buffering of data is done. Hence, for efficieny #read(byte[]) should be used instead of #read(). Marks are not supported, but it should be pretty simple to extend the implementation to support this. A more efficient skip implementation should also be straight-forward.

Field Summary

private Clob	clob The Clob to be accessed.
private Connection	connection Connection used to read Clob from server.
private long	currentPos Current position in the underlying Clob.

Constructor Summary

ClobLocatorInputStream(Connection connection, Clob clob)
Create an InputStream for reading the Clob value represented by the given locator based Clob object.

ClobLocatorInputStream(Connection connection, Clob clob, long pos)
Create an InputStream for reading the Clob value represented by the given locator based Clob object.

Method Summary

private byte[]	getBytesFromString(java.lang.String str) Returns a Byte array from the String passed as Input.
int	read()
int	read(byte[] b, int off, int len)
private byte[]	readBytes(int len) Read the next len bytes of the Clob value from the server.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

connection

private final Connection connection

Connection used to read Clob from server.

clob

private final Clob clob

The Clob to be accessed.

currentPos

private long currentPos

Current position in the underlying Clob. Clobs are indexed from 1

Constructor Detail

ClobLocatorInputStream

public ClobLocatorInputStream(Connection connection,
                              Clob clob)
                       throws SqlException

Create an InputStream for reading the Clob value represented by the given locator based Clob object.

Parameters:

connection - connection to be used to read the Clob value from the server

clob - Clob object that contains locator for the Clob value on the server.

Throws:

SqlException

ClobLocatorInputStream

public ClobLocatorInputStream(Connection connection,
                              Clob clob,
                              long pos)
                       throws SqlException

Create an InputStream for reading the Clob value represented by the given locator based Clob object.

Parameters:

connection - connection to be used to read the Clob value from the server

clob - Clob object that contains locator for the Clob value on the server.

pos - the position inside the Clob from which the reading must begin.

Throws:

SqlException

Method Detail

read

public int read()
         throws java.io.IOException

Specified by:

read in class java.io.InputStream

Throws:

java.io.IOException

See Also:

This method fetches one byte at a time from the server. For more efficient retrieval, use #read(byte[]).

read

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

Overrides:

read in class java.io.InputStream

Throws:

java.io.IOException

See Also:

InputStream.read(byte[], int, int)

readBytes

private byte[] readBytes(int len)
                  throws java.io.IOException

Read the next len bytes of the Clob value from the server.

Parameters:

len - number of bytes to read

Returns:

byte[] containing the read bytes

Throws:

java.io.IOException - Wrapped SqlException if reading from server fails.

getBytesFromString

private byte[] getBytesFromString(java.lang.String str)

Returns a Byte array from the String passed as Input.

Parameters:

str - the input String.

Returns:

The Byte corresponding to the String that was input.