com.sleepycat.bind.tuple
Class TupleBase<E>

java.lang.Object
  com.sleepycat.bind.tuple.TupleBase<E>

Direct Known Subclasses:

TupleBinding, TupleSerialBinding, TupleSerialKeyCreator, TupleTupleBinding, TupleTupleKeyCreator

public class TupleBase<E>
extends Object

A base class for tuple bindings and tuple key creators that provides control over the allocation of the output buffer.

Tuple bindings and key creators append data to a TupleOutput instance, which is also a FastOutputStream instance. This object has a byte array buffer that is resized when it is full. The reallocation of this buffer can be a performance factor for some applications using large objects. To manage this issue, the setTupleBufferSize(int) method may be used to control the initial size of the buffer, and the getTupleOutput(E) method may be overridden by subclasses to take over creation of the TupleOutput object.

TupleBase

public TupleBase()

Initializes the initial output buffer size to zero.

Unless setTupleBufferSize(int) is called, the default FastOutputStream.DEFAULT_INIT_SIZE size will be used.

setTupleBufferSize

public void setTupleBufferSize(int byteSize)

Sets the initial byte size of the output buffer that is allocated by the default implementation of getTupleOutput(E).

If this property is zero (the default), the default FastOutputStream.DEFAULT_INIT_SIZE size is used.

Parameters:

byteSize - the initial byte size of the output buffer, or zero to use the default size.

getTupleBufferSize

public int getTupleBufferSize()

Returns the initial byte size of the output buffer.

Returns:

the initial byte size of the output buffer.

See Also:

setTupleBufferSize(int)

getTupleOutput

protected TupleOutput getTupleOutput(E object)

Returns an empty TupleOutput instance that will be used by the tuple binding or key creator.

The default implementation of this method creates a new TupleOutput with an initial buffer size that can be changed using the setTupleBufferSize(int) method.

This method may be overridden to return a TupleOutput instance. For example, an instance per thread could be created and returned by this method. If a TupleOutput instance is reused, be sure to call its FastOutputStream.reset() method before each use.

Parameters:

object - is the object to be written to the tuple output, and may be used by subclasses to determine the size of the output buffer.

Returns:

an empty TupleOutput instance.

See Also:

setTupleBufferSize(int)

outputToEntry

public static void outputToEntry(TupleOutput output,
                                 DatabaseEntry entry)

Utility method to set the data in a entry buffer to the data in a tuple output object.

Parameters:

output - is the source tuple output object.

entry - is the destination entry buffer.

inputToEntry

public static void inputToEntry(TupleInput input,
                                DatabaseEntry entry)

Utility method to set the data in a entry buffer to the data in a tuple input object.

Parameters:

input - is the source tuple input object.

entry - is the destination entry buffer.

entryToInput

public static TupleInput entryToInput(DatabaseEntry entry)

Utility method to create a new tuple input object for reading the data from a given buffer. If an existing input is reused, it is reset before returning it.

Parameters:

entry - is the source entry buffer.

Returns:

the new tuple input object.

newOutput

public static TupleOutput newOutput()

Deprecated. replaced by getTupleOutput(E)

Utility method for use by bindings to create a tuple output object.

Returns:

a new tuple output object.

newOutput

public static TupleOutput newOutput(byte[] buffer)

Deprecated. replaced by getTupleOutput(E)

Utility method for use by bindings to create a tuple output object with a specific starting size.

Returns:

a new tuple output object.