net.kwfgrid.gwes.uiproxy.jdom
Class JDOMSequenceBuffer

java.lang.Object
  net.kwfgrid.gwes.uiproxy.AbstractBuffer
      net.kwfgrid.gwes.uiproxy.SequenceBuffer
          net.kwfgrid.gwes.uiproxy.jdom.JDOMSequenceBuffer

All Implemented Interfaces:

Buffer, Consumer

public abstract class JDOMSequenceBuffer
extends SequenceBuffer

Implementation of SequenceBuffer for sequenced XML messages in the JDOM object model. The sequence number of the messages must be accessible by an XPath query. The jaxen XPath engine is used to query incoming messages for their sequence number.

This buffer supports the following properties:

• Buffer.size
• SequenceBuffer.first
• JDOMSequenceBuffer.xpath_sequenceNumber
• JDOMSequenceBuffer.xpath_shouldHandle

The JDOMSequenceBuffer.* properties must be set at initialization time of the buffer.

Field Summary

static String	XPATH_SEQUENCE_NUMBER_PROPERTY_KEY
static String	XPATH_SHOULD_HANDLE_PROPERTY_KEY

Fields inherited from class net.kwfgrid.gwes.uiproxy.SequenceBuffer

_content, _exception, _first, _initialized, _precontent, FIRST_PROPERTY_KEY

Fields inherited from class net.kwfgrid.gwes.uiproxy.AbstractBuffer

_id, _size, DEFAULT_SIZE, SIZE_PROPERTY_KEY

Constructor Summary

JDOMSequenceBuffer(String xpath)
Constructor.

Method Summary

protected int	getSequenceNumber(Object message) Generic method to access the sequence number of the specified message.
void	setProperty(String key, String value) This implementation only interprets the Buffer.size property.
protected boolean	shouldHandle(Object message) This buffer handles messages which are instance of org.jdom.Element.

Methods inherited from class net.kwfgrid.gwes.uiproxy.SequenceBuffer

handle, initialize, read, setSize

Methods inherited from class net.kwfgrid.gwes.uiproxy.AbstractBuffer

getID, getSize, setID, setProperties

Methods inherited from class java.lang.Object

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

Field Detail

XPATH_SEQUENCE_NUMBER_PROPERTY_KEY

public static final String XPATH_SEQUENCE_NUMBER_PROPERTY_KEY

See Also:

Constant Field Values

XPATH_SHOULD_HANDLE_PROPERTY_KEY

public static final String XPATH_SHOULD_HANDLE_PROPERTY_KEY

See Also:

Constant Field Values

Constructor Detail

JDOMSequenceBuffer

public JDOMSequenceBuffer(String xpath)
                   throws InstantiationException

Constructor.

Parameters:

xpath - The XPath expression to access the sequence number inside of an incoming message.

Throws:

InstantiationException - If the XPath string could not be parsed.

Method Detail

setProperty

public void setProperty(String key,
                        String value)
                 throws BufferException

Description copied from class: AbstractBuffer

This implementation only interprets the Buffer.size property.

Specified by:

setProperty in interface Buffer

Overrides:

setProperty in class SequenceBuffer

Throws:

BufferException

getSequenceNumber

protected int getSequenceNumber(Object message)
                         throws org.jaxen.JaxenException,
                                NumberFormatException,
                                IllegalStateException

Description copied from class: SequenceBuffer

Generic method to access the sequence number of the specified message. Sequence numbers are expected to be positive integers.

Specified by:

getSequenceNumber in class SequenceBuffer

Throws:

IllegalStateException - If the property JDOMSequenceBuffer.xpath_sequenceNumber is not set.

org.jaxen.JaxenException

NumberFormatException

shouldHandle

protected boolean shouldHandle(Object message)
                        throws org.jaxen.JaxenException,
                               IllegalStateException

This buffer handles messages which are instance of org.jdom.Element. Additionally the XPath expression provided through property JDOMSequenceBuffer.xpath_shouldHandle must evaluate to true for the incoming message.

Specified by:

shouldHandle in class SequenceBuffer

Throws:

IllegalStateException - If the property JDOMSequenceBuffer.xpath_shouldHandle is not set.

org.jaxen.JaxenException