net.sf.saxon.event

Class CheckSumFilter

java.lang.Object

net.sf.saxon.event.SequenceReceiver

net.sf.saxon.event.ProxyReceiver

net.sf.saxon.event.CheckSumFilter

All Implemented Interfaces:

Result, Receiver

public class CheckSumFilter
extends ProxyReceiver

A filter to go on a Receiver pipeline and calculate a checksum of the data passing through the pipeline. Optionally the filter will also check any checksum (represented by a processing instruction with name SIGMA) found in the file.

The checksum takes account of element, attribute, and text nodes only. The order of attributes within an element makes no difference.

Field Summary

Fields

Modifier and Type	Field and Description
static String	SIGMA

Fields inherited from class net.sf.saxon.event.ProxyReceiver

nextReceiver

Fields inherited from class net.sf.saxon.event.SequenceReceiver

pipelineConfiguration, previousAtomic, systemId

Fields inherited from interface javax.xml.transform.Result

PI_DISABLE_OUTPUT_ESCAPING, PI_ENABLE_OUTPUT_ESCAPING

Constructor Summary

Constructors

Constructor and Description
CheckSumFilter(Receiver nextReceiver)

Method Summary

Methods

Modifier and Type	Method and Description
void	append(Item item, Location locationId, int copyNamespaces) Append an arbitrary item (node or atomic value) to the output
void	attribute(NodeName nameCode, SimpleType typeCode, CharSequence value, Location locationId, int properties) Notify an attribute.
void	characters(CharSequence chars, Location locationId, int properties) Character data
void	endElement() End of element
int	getChecksum() Get the accumulated checksum
boolean	isChecksumCorrect() Ask if a correct checksum has been found in the file
boolean	isChecksumFound() Ask whether a checksum has been found
void	processingInstruction(String target, CharSequence data, Location locationId, int properties) Processing Instruction
void	setCheckExistingChecksum(boolean check) Ask the filter to check any existing checksums found in the file
void	startElement(NodeName elemName, SchemaType typeCode, Location location, int properties) Notify the start of an element

Methods inherited from class net.sf.saxon.event.ProxyReceiver

close, comment, endDocument, getNamePool, getUnderlyingReceiver, namespace, open, setPipelineConfiguration, setSystemId, setUnderlyingReceiver, setUnparsedEntity, startContent, startDocument, usesTypeAnnotations

Methods inherited from class net.sf.saxon.event.SequenceReceiver

append, getConfiguration, getPipelineConfiguration, getSystemId, isTrueSequenceReceiver

Methods inherited from class java.lang.Object

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

Field Detail

SIGMA

public static final String SIGMA

See Also:

Constant Field Values

Constructor Detail

CheckSumFilter

public CheckSumFilter(Receiver nextReceiver)

Method Detail

setCheckExistingChecksum

public void setCheckExistingChecksum(boolean check)

Ask the filter to check any existing checksums found in the file

Parameters:

check - true if existing checksums are to be checked

append

public void append(Item item,
          Location locationId,
          int copyNamespaces)
            throws XPathException

Append an arbitrary item (node or atomic value) to the output

Overrides:

append in class ProxyReceiver

Parameters:

item - the item to be appended

locationId - the location of the calling instruction, for diagnostics

copyNamespaces - if the item is an element node, this indicates whether its namespaces need to be copied. Values are NodeInfo.ALL_NAMESPACES, NodeInfo.LOCAL_NAMESPACES, NodeInfo.NO_NAMESPACES

Throws:

XPathException - if the operation fails

attribute

public void attribute(NodeName nameCode,
             SimpleType typeCode,
             CharSequence value,
             Location locationId,
             int properties)
               throws XPathException

Notify an attribute. Attributes are notified after the startElement event, and before any children. Namespaces and attributes may be intermingled.

Specified by:

attribute in interface Receiver

Overrides:

attribute in class ProxyReceiver

Parameters:

nameCode - The name of the attribute, as held in the name pool

typeCode - The type of the attribute, as held in the name pool

value - The attribute value

locationId - The location of the attribute

properties - Bit significant value. The following bits are defined:

DISABLE_ESCAPING

Disable escaping for this attribute

NO_SPECIAL_CHARACTERS

Attribute value contains no special characters

@throws IllegalStateException: attempt to output an attribute when there is no open element

Throws:

XPathException - if an error occurs

characters

public void characters(CharSequence chars,
              Location locationId,
              int properties)
                throws XPathException

Character data

Specified by:

characters in interface Receiver

Overrides:

characters in class ProxyReceiver

Parameters:

chars - The characters

locationId - provides information such as line number and system ID.

properties - Bit significant value. The following bits are defined:

DISABLE_ESCAPING

Disable escaping for this text node

USE_CDATA

Output as a CDATA section

Throws:

XPathException - if an error occurs

startElement

public void startElement(NodeName elemName,
                SchemaType typeCode,
                Location location,
                int properties)
                  throws XPathException

Notify the start of an element

Specified by:

startElement in interface Receiver

Overrides:

startElement in class ProxyReceiver

Parameters:

elemName - integer code identifying the name of the element within the name pool.

typeCode - integer code identifying the element's type within the name pool.

location - location of the element

properties - properties of the element node

Throws:

XPathException - if an error occurs

endElement

public void endElement()
                throws XPathException

End of element

Specified by:

endElement in interface Receiver

Overrides:

endElement in class ProxyReceiver

Throws:

XPathException - if an error occurs

processingInstruction

public void processingInstruction(String target,
                         CharSequence data,
                         Location locationId,
                         int properties)
                           throws XPathException

Processing Instruction

Specified by:

processingInstruction in interface Receiver

Overrides:

processingInstruction in class ProxyReceiver

Parameters:

target - The PI name. This must be a legal name (it will not be checked).

data - The data portion of the processing instruction

locationId - provides information such as line number and system ID.

properties - Additional information about the PI.

Throws:

XPathException - if an error occurs

isChecksumFound

public boolean isChecksumFound()

Ask whether a checksum has been found

Returns:

true if a checksum processing instruction has been found (whether or not the checksum was correct)

getChecksum

public int getChecksum()

Get the accumulated checksum

Returns:

the checksum of the events passed through the filter so far.

isChecksumCorrect

public boolean isChecksumCorrect()

Ask if a correct checksum has been found in the file

Returns:

true if a checksum has been found, if its value matches, and if no significant data has been encountered after the checksum