com.lf.commons.web.msg

Class XMLMessage

java.lang.Object

com.lf.commons.web.msg.XMLMessage

All Implemented Interfaces:

AbstractMessage

Direct Known Subclasses:

AntMessage, DatabaseUpdate, DateMessage, ErrorMessage, License, MapMessage, ModelConfig, ParameterMessage, PingMessage, ReleaseNotes, StatusReport, UpdateMessage

public abstract class XMLMessage
extends java.lang.Object
implements AbstractMessage

Base class for representing an XML document used for database updates (both DDL and DML).

The data is stored as XML document internally which is based on a certain document type definition (DTD). Sub classes must specifiy an underlying DTD for the XML payload and overwrite the two canProcess() methods.

Since:

1.6

Version:

$Revision: 1.19 $, $Date: 2012/12/28 11:44:25 $

Author:

Axel Schwolow

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	docname Name of the root element.
protected org.jdom.Document	document XML document to be processed.
protected java.net.URL	dtd Name of the corresponding XML document type definition (DTD), set by sub class.
protected java.lang.String	encoding Original encoding of the document.
protected org.jdom.output.Format	format Name of the root element.

Constructor Summary

Constructors

Constructor and Description
XMLMessage() Constructor method for i18n purposes only.
XMLMessage(java.net.URL dtd, java.lang.String docname) Constructs an instance based on a given DTD.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canProcess(java.io.InputStream istream) Checks whether the given input stream can be read/written by this message.
org.jdom.Attribute	getAttribute(java.lang.String expression) Provides an XML attribute on basis of an XPath expression.
java.lang.String	getAttributeValue(java.lang.String expression) Provides an XML attribute value on basis of an XPath expression.
java.lang.String	getContents(java.lang.String encoding) Provides the formatted XML document for debugging.
org.jdom.Document	getDocument() Provides the internally used XML document.
java.net.URL	getDTD() Provides the URL to load the associated DTD for validation purposes.
org.jdom.Element	getElement(java.lang.String expression) Provides an XML element on basis of an XPath expression.
java.util.List	getElements(java.lang.String expression) Provides a list of XML elements on basis of an XPath expression.
java.lang.String	getElementValue(java.lang.String expression) Provides an XML element value on basis of an XPath expression.
java.lang.String	getEncoding() Provides the document encoding.
int	getIntFunctionResult(java.lang.String expression) Provides an XML function value on basis of an XPath expression.
boolean	isArmed() Has the message successfully been loaded with payload?
boolean	isValid() Determines whether the message contents are valid and can be used.
void	printDocument(java.lang.String encoding) Prints the formatted XML document via System.out.
boolean	read(byte[] data) Reads the message contents from the given binary data array (convenience).
boolean	read(java.io.InputStream istream) Reads the message contents from the given input stream.
void	setEncoding(java.lang.String encoding) Sets the document encoding.
void	setFormat(org.jdom.output.Format format) Overrides the default format Format.getPrettyFormat().
boolean	write(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Generates response message data with the given servlet response.
boolean	write(java.io.OutputStream ostream, java.lang.String encoding) Generates response message data with the given output stream.

Methods inherited from class java.lang.Object

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

Field Detail

document

protected org.jdom.Document document

XML document to be processed.

dtd

protected java.net.URL dtd

Name of the corresponding XML document type definition (DTD), set by sub class.

docname

protected java.lang.String docname

Name of the root element.

format

protected org.jdom.output.Format format

Name of the root element.

encoding

protected java.lang.String encoding

Original encoding of the document.

Constructor Detail

XMLMessage

public XMLMessage()
           throws java.lang.InstantiationException

Constructor method for i18n purposes only.

Can only be used if beans design time is set (e.g. by external tools like the I18NExtractor).

Throws:

java.lang.InstantiationException - Error indication

Since:

1.6

XMLMessage

public XMLMessage(java.net.URL dtd,
          java.lang.String docname)

Constructs an instance based on a given DTD.

Parameters:

dtd - The document type definition, required

docname - Name of the root element

Throws:

java.lang.NullPointerException - If parameter is invalid

Method Detail

canProcess

public boolean canProcess(java.io.InputStream istream)

Checks whether the given input stream can be read/written by this message.

Remember that the message class may read some data from the stream which has to be reset afterwards. So better use a BufferedInputStream and mark the position before this method is called. Reset the stream when the method has done its job to allow other messages to perform another lookahead properly.

Specified by:

canProcess in interface AbstractMessage

Parameters:

istream - Input stream with incoming message

Returns:

Processing possible?

Throws:

java.lang.NullPointerException - Parameter was null

read

public boolean read(java.io.InputStream istream)
             throws java.io.IOException

Reads the message contents from the given input stream.

Specified by:

read in interface AbstractMessage

Parameters:

istream - Input stream with incoming message

Returns:

Successful?

Throws:

java.io.IOException - An I/O error occurred

java.lang.NullPointerException - Parameter was null

read

public boolean read(byte[] data)
             throws java.io.IOException

Reads the message contents from the given binary data array (convenience).

Parameters:

data - Binary message data

Returns:

Successful?

Throws:

java.io.IOException - An I/O error occurred

java.lang.NullPointerException - Parameter was null

Since:

1.6

write

public boolean write(java.io.OutputStream ostream,
            java.lang.String encoding)
              throws java.io.IOException

Generates response message data with the given output stream.

Specified by:

write in interface AbstractMessage

Parameters:

ostream - Output stream for outgoing message

encoding - Encoding for stream, may be null

Returns:

Successful?

Throws:

java.io.IOException - An I/O error occurred

java.lang.NullPointerException - Parameter was null

write

public boolean write(javax.servlet.http.HttpServletRequest request,
            javax.servlet.http.HttpServletResponse response)
              throws java.io.IOException

Generates response message data with the given servlet response.

Specified by:

write in interface AbstractMessage

Parameters:

request - Servlet request with incoming message

response - Servlet response for outgoing message

Returns:

Successful?

Throws:

java.io.IOException - An I/O error occurred

java.lang.NullPointerException - Parameter was null

isArmed

public boolean isArmed()

Has the message successfully been loaded with payload?

Specified by:

isArmed in interface AbstractMessage

Returns:

Contents available?

isValid

public boolean isValid()

Determines whether the message contents are valid and can be used.

Specified by:

isValid in interface AbstractMessage

Returns:

Contents valid?

getDTD

public java.net.URL getDTD()

Provides the URL to load the associated DTD for validation purposes.

Returns:

URL to load DTD from class path

getAttribute

public org.jdom.Attribute getAttribute(java.lang.String expression)

Provides an XML attribute on basis of an XPath expression.

An XPath expression looks like "/KLINIK_RESERVIERUNG/KLINIK/@IKNR".

Parameters:

expression - XPath expression

Returns:

Attribute, null else

getAttributeValue

public java.lang.String getAttributeValue(java.lang.String expression)

Provides an XML attribute value on basis of an XPath expression.

An XPath expression looks like "/KLINIK_RESERVIERUNG/KLINIK/@IKNR".

Parameters:

expression - XPath expression

Returns:

Attribute value, null else

getElement

public org.jdom.Element getElement(java.lang.String expression)

Provides an XML element on basis of an XPath expression.

An XPath expression looks like "/KLINIK_RESERVIERUNG/KLINIK".

Parameters:

expression - XPath expression

Returns:

Element, null else

getElementValue

public java.lang.String getElementValue(java.lang.String expression)

Provides an XML element value on basis of an XPath expression.

An XPath expression looks like "/KLINIK_RESERVIERUNG/KLINIK".

Parameters:

expression - XPath expression

Returns:

Element value, null else

getElements

public java.util.List getElements(java.lang.String expression)

Provides a list of XML elements on basis of an XPath expression.

An XPath expression looks like "/KLINIK_RESERVIERUNG/KLINIK".

Parameters:

expression - XPath expression

Returns:

Element list, null else

getIntFunctionResult

public int getIntFunctionResult(java.lang.String expression)

Provides an XML function value on basis of an XPath expression.

An XPath expression looks like "count(/DISPO_ANFRAGE/DISPOSITION)".

Parameters:

expression - XPath expression

Returns:

Function value, null else

printDocument

public void printDocument(java.lang.String encoding)

Prints the formatted XML document via System.out.

If executed by the Tomcat web container the output normally goes into the log file.

Parameters:

encoding - Like "ISO-8859-1"

getContents

public java.lang.String getContents(java.lang.String encoding)

Provides the formatted XML document for debugging.

Parameters:

encoding - Like "ISO-8859-1"

Returns:

The document contents as formatted XML, null in error case

setFormat

public void setFormat(org.jdom.output.Format format)

Overrides the default format Format.getPrettyFormat().

Parameters:

format - Supported format (required)

Throws:

java.lang.NullPointerException - If parameter is null

getDocument

public org.jdom.Document getDocument()

Provides the internally used XML document.

Returns:

XML document, may be null

setEncoding

public void setEncoding(java.lang.String encoding)

Sets the document encoding.

Parameters:

encoding - The encoding (optional)

getEncoding

public java.lang.String getEncoding()

Provides the document encoding.

Returns:

The encoding, may be null