uk.org.ogsadai.activity.delivery
Class AbstractDeliverFromAddressActivity

java.lang.Object
  |
  +--uk.org.ogsadai.activity.Activity
        |
        +--uk.org.ogsadai.activity.delivery.AbstractDeliverFromAddressActivity

Direct Known Subclasses:

DeliverFromFileActivity, DeliverFromURLActivity

public abstract class AbstractDeliverFromAddressActivity

extends Activity

This abstract class contains methods to connect to a java.io.InputStream and pull all the information on that stream into OGSA-DAI, either in one byte array block, or via multiple set sized byte array blocks.

The output can then be connected to the input of another activity,

Author:

The OGSA-DAI Project Team

COPYRIGHT_NOTICE

private static final java.lang.String COPYRIGHT_NOTICE

Copyright statement

See Also:

Constant Field Values

LOG

private static final DAILogger LOG

Logger object for logging in this class

mFromAddress

protected java.lang.String mFromAddress

Address to read data from

mFromInputStream

protected java.io.InputStream mFromInputStream

Input stream configured to read data from the address

mBlockMode

protected boolean mBlockMode

Size of blocks placed onto the stream

mBuffer

protected byte[] mBuffer

Buffer to hold data

mByteBuffer

protected final java.io.ByteArrayOutputStream mByteBuffer

ByteArrayOutputStream to hold output data

mOutput

protected BlockWriter mOutput

Activity output - data read from address

AbstractDeliverFromAddressActivity

public AbstractDeliverFromAddressActivity(org.w3c.dom.Element element)
                                   throws ActivityCreationException,
                                          ActivitySpecificationException

setupBlocking

protected void setupBlocking(org.w3c.dom.Element fromElement)
                      throws ActivitySpecificationException,
                             ActivityExecutionException

Gets the block size, in bytes, from a blockSizeInBytes attribute of the given element and saves this in an instance variable.

Parameters:

fromElement - Element from the request.

Throws:

ActivitySpecificationException - If the block size is not an integer > 0.

ActivityExecutionException - If there is not enough memory.

setupOutput

protected void setupOutput(org.w3c.dom.Element toElement)

Gets the name of the activity output stream from a name attribute of the given element and saves this in the activity's list of internal outputs.

Parameters:

toElement - Element from the request.

initialise

public void initialise()
                throws ActivitySpecificationException,
                       ActivityExecutionException

Description copied from class: Activity

This method should be overridden by subclasses to perform any initialisation they require before the process method invocations begin. This might be used for setting up convenient fields to reference objects contained in the context. It shouldn't be used for opening resources. That should be done in processFirst.

Overrides:

initialise in class Activity

Throws:

ActivityExecutionException - If some system problem prevents the activity from initialising.

ActivitySpecificationException - If a problem with settings provided by a client prevents the activity from initialising.

processFirst

public abstract void processFirst()

Description copied from class: Activity

This method is called during the first iteration of processing an activity. It can be overridden by subclasses to define some processing that should be done only once during the first iteration of the activity processing, for example evaluating a database query.

Overrides:

processFirst in class Activity

processBlock

public void processBlock()

Description copied from class: Activity

Performs an iteration of the processing of an activity. This may involve reading a block of input data and writing a block of output data, or may involve some other kind of processing. When an activity is processed by the OGSA-DAI engine, this method will be invoked repeatedly until the activity either completes or stops due to an error or termination call. An implementation of this method should invoke the setCompleted method to indicate that processing is complete, or the setError method if an error occurs that will prevent the processing from completing.

Specified by:

processBlock in class Activity