net.sf.xbus.protocol.xml
Class XSLTTransformer

java.lang.Object
  net.sf.xbus.protocol.xml.XSLTTransformer

All Implemented Interfaces:

Transformer

Direct Known Subclasses:

RecordTypeTransformer

public class XSLTTransformer
extends java.lang.Object
implements Transformer

This is the base class for all transformation between XMLMessages with XSLT stylesheets.

The transformation is done in two steps:

1. An XSLT stylesheet which name is read from the configuration does the first part of the transformation.
2. The so-called XBUS_Stylets are processed to fill in extra data into the XML data.

XBUS_Stylets:

XSLT stylesheets lack the possibilty to fill in data to the transformed XML data which cannot be extracted out of the source XML. To fill this gap some defined tags can be included in the transformed XML when the XSLT transformation is done. These tags are replaced in the second step with defined data. The format for XBUS_Stylets is:

      <XBUS_Stylet Name="xxx" Tag="yyy" Key="zzz">
 

The XSLT code to achieve this looks like:

      <xsl:element name="XBUS_Stylet">
          <xsl:attribute name="Name">xxx</xsl:attribute>
          <xsl:attribute name="Tag">yyy</xsl:attribute>
          <xsl:attribute name="Key">zzz</xsl:attribute>
      </xsl:element>
 

The meaning of the attributes is:

• Name: The name defines what data is inserted. There is a defined set of names which will be explained in the following list.
• Tag: The name of the tag under which the data is inserted.
  May be omitted if Name="Value" or Name="FormatDate". In this case only a text node for the value is inserted.
• Section: Optional, only used with the name Value. Specifies the name of the mapping to get a value from.
• Key: Optional, only used with the names Value, CDATA and FormatDate. Values come from two different sources depending on the section attribute.
  If no section is specified: A key/value pair can be stored before the transformation (see method putStyletValue). The value for the given key is inserted.
  For a given section: The value is read by the getMapping operation of the Configuration.
• SourceFormat: Optional, only used with the name FormatDate. Describes the actual format of the date given in Key.
• DestinationFormat: Optional, only used with the name FormatDate. Describes the format to apply to the date given in Key.

The values for the attribute Name are defined as follows:

• Id: The identifier of the new Message is inserted.
• Source: The logical name of the source of the Message is inserted.
• RequestTimestamp: The request timestamp is inserted.
• Value: The value for the given key (see above) is inserted.
• CDATA: The value for the given key (see above) is inserted as a CDATA section.
• FormatDate: The format for the given date in key (see above) is changed. SourceFormat describes the original and DestinationFormat the new format.

If a transformation between XMLMessages can be done directly via a XSLT stylesheet and XBUS_Stylet processing, this class can be used. When extra code is needed for the transformation, it has to be subclassed.

Field Summary

protected static java.lang.String

XSL_LOCATION

Constructor Summary

XSLTTransformer()

Method Summary

protected XMLMessageAbstract	createMessage(XBUSSystem destination, XMLMessageAbstract source) Creates an object which is suitable for sending data to the given system.
protected javax.xml.transform.Transformer	getXSLTransformer(java.lang.String xslFile) Returns a Transformer object needed for the XSLT processing.
void	putStyletValue(java.lang.Object key, java.lang.Object value) Stores a key/value pair which is used later in the processing of the XBUS_Stylets.
java.lang.Object	transform(java.lang.Object inObject, XBUSSystem source, XBUSSystem destination, Message destinationMessage) The transform method is automatically called by the xBus during the routing of messages.
protected org.w3c.dom.Document	transformXML(org.w3c.dom.Document xmlOld, java.lang.String xslFile, Message message) Transforms the given XML-data with the given XSL-stylesheet.

Methods inherited from class java.lang.Object

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

Field Detail

XSL_LOCATION

protected static final java.lang.String XSL_LOCATION

Constructor Detail

XSLTTransformer

public XSLTTransformer()

Method Detail

transform

public java.lang.Object transform(java.lang.Object inObject,
                                  XBUSSystem source,
                                  XBUSSystem destination,
                                  Message destinationMessage)
                           throws XException

The transform method is automatically called by the xBus during the routing of messages.

Specified by:

transform in interface Transformer

Parameters:

inObject - either the request or response that shall be transformed to another format

source - the XBUSSystem of the message of the inObject

destination - the XBUSSystem of the target message

destinationMessage - the target message eventually contains more information necessary for transforming

Returns:

the transformed Object, written to either the request or response of the target message

Throws:

XException

putStyletValue

public void putStyletValue(java.lang.Object key,
                           java.lang.Object value)

Stores a key/value pair which is used later in the processing of the XBUS_Stylets.

transformXML

protected org.w3c.dom.Document transformXML(org.w3c.dom.Document xmlOld,
                                            java.lang.String xslFile,
                                            Message message)
                                     throws XException

Transforms the given XML-data with the given XSL-stylesheet. After the XSL-transformation the so-called XBUS_Stylets are processed.

Parameters:

xmlOld - the source XML-data

xslFile - the name of the XSL-stylesheet

message - the destination message

Throws:

XException - if something goes wrong

getXSLTransformer

protected javax.xml.transform.Transformer getXSLTransformer(java.lang.String xslFile)
                                                     throws XException

Returns a Transformer object needed for the XSLT processing. The Transformers are cached for every thread and every XSLT stylesheet.

Throws:

XException

createMessage

protected XMLMessageAbstract createMessage(XBUSSystem destination,
                                           XMLMessageAbstract source)
                                    throws XException

Creates an object which is suitable for sending data to the given system. The name of the class is read in the <@link net.sf.xbus.base.core.Configuration>. The returned class must be a subclass of XMLMessage.

Throws:

XException