Class ClobLocatorInputStream

java.lang.Object

java.io.InputStream

org.apache.derby.client.am.ClobLocatorInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

class ClobLocatorInputStream
extends 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 efficiency #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

Fields

Modifier and Type	Field	Description
private final ClientClob	clob	The Clob to be accessed.
private final ClientConnection	connection	Connection used to read Clob from server.
private long	currentPos	Current position in the underlying Clob.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
private byte[]	getBytesFromString(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 InputStream

available, close, mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, reset, skip, skipNBytes, transferTo

Methods inherited from class Object

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

Field Details

connection

private final ClientConnection connection

Connection used to read Clob from server.

clob

private final ClientClob clob

The Clob to be accessed.

currentPos

private long currentPos

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

Constructor Details

ClobLocatorInputStream

ClobLocatorInputStream(ClientConnection connection,
 ClientClob 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

ClobLocatorInputStream(ClientConnection connection,
 ClientClob 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 Details

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

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 IOException

Overrides:

read in class InputStream

Throws:

IOException

See Also:

• InputStream.read(byte[], int, int)

readBytes

private byte[] readBytes(int len)
                  throws 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:

IOException - Wrapped SqlException if reading from server fails.

getBytesFromString

private byte[] getBytesFromString(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.