org.apache.camel.builder.xml
Class XPathBuilder

java.lang.Object
  org.apache.camel.support.ServiceSupport
      org.apache.camel.builder.xml.XPathBuilder

All Implemented Interfaces:

Expression, Predicate, Service, ShutdownableService, NamespaceAware, StatefulService, SuspendableService

public class XPathBuilder
extends ServiceSupport
implements Expression, Predicate, NamespaceAware

Creates an XPath expression builder which creates a nodeset result by default. If you want to evaluate a String expression then call stringResult()

An XPath object is not thread-safe and not reentrant. In other words, it is the application's responsibility to make sure that one XPath object is not used from more than one thread at any given time, and while the evaluate method is invoked, applications may not recursively call the evaluate method.

This implementation is thread safe by using thread locals and pooling to allow concurrency.

Important: After configuring the XPathBuilder its adviced to invoke ServiceSupport.start() to prepare the builder before using; though the builder will auto-start on first use.

See Also:

XPathConstants.NODESET

Field Summary

Fields inherited from class org.apache.camel.support.ServiceSupport

shutdown, shuttingdown, started, starting, stopped, stopping, suspended, suspending

Constructor Summary

XPathBuilder(String text)

Method Summary

XPathBuilder	booleanResult() Sets the expression result type to boolean
protected XPathFunctionResolver	createDefaultFunctionResolver(XPathFunctionResolver parent)
protected DefaultNamespaceContext	createNamespaceContext(XPathFactory factory)
protected XPathExpression	createTraceNamespaceExpression()
protected XPathExpression	createXPathExpression() Creates a new xpath expression as there we no available in the pool.
protected XPathFactory	createXPathFactory()
XPathBuilder	documentType(Class<?> documentType) Configures the document type to use.
protected Object	doGetDocument(Exchange exchange, Object body)
protected Object	doInEvaluateAs(XPathExpression xpathExpression, Exchange exchange, QName resultQName)
void	doStart() Implementations override this method to support customized start/stop.
void	doStop() Implementations override this method to support customized start/stop.
void	enableSaxon() Enables Saxon on this particular XPath expression, as saxon() sets the default static XPathFactory which may have already been initialised by previous XPath expressions
String	evaluate(CamelContext context, Object body) Evaluates the given xpath using the provided body as a String return type.
<T> T	evaluate(CamelContext context, Object body, Class<T> type) Evaluates the given xpath using the provided body.
protected Object	evaluate(Exchange exchange)
<T> T	evaluate(Exchange exchange, Class<T> type) Returns the value of the expression on the given exchange
protected Object	evaluateAs(Exchange exchange, QName resultQName) Evaluates the expression as the given result type
XPathBuilder	factory(XPathFactory xpathFactory) Configures to use the provided XPath factory.
XPathBuilder	functionResolver(XPathFunctionResolver functionResolver) Sets the XPathFunctionResolver instance to use on these XPath expressions
XPathFunction	getBodyFunction() Gets the XPathFunction for getting the input message body.
protected Object	getDocument(Exchange exchange, Object body) Strategy method to extract the document from the exchange.
Class<?>	getDocumentType()
XPathFunctionResolver	getFunctionResolver()
XPathFunction	getHeaderFunction() Gets the XPathFunction for getting the input message header.
DefaultNamespaceContext	getNamespaceContext() Gets the namespace context, can be null if no custom context has been assigned.
String	getObjectModelUri()
XPathFunction	getOutBodyFunction() Gets the XPathFunction for getting the output message body.
XPathFunction	getOutHeaderFunction() Gets the XPathFunction for getting the output message header.
XPathFunction	getPropertiesFunction() Gets the XPathFunction for getting the exchange properties.
QName	getResultQName()
Class<?>	getResultType()
XPathFunction	getSimpleFunction() Gets the XPathFunction for executing simple language as xpath function.
String	getText()
XPathFactory	getXPathFactory() Gets the xpath factory, can be null if no custom factory has been assigned.
protected void	initDefaultXPathFactory()
protected boolean	isInputStreamNeeded(Exchange exchange) Checks whether we need an InputStream to access the message body.
boolean	isLogNamespaces()
XPathBuilder	logNamespaces() Activates trace logging of all discovered namespaces in the message - to simplify debugging namespace-related issues Namespaces are printed in Hashmap style {xmlns:prefix=[namespaceURI], xmlns:prefix=[namespaceURI]}.
boolean	matches(CamelContext context, Object body) Matches the given xpath using the provided body.
boolean	matches(Exchange exchange) Evaluates the predicate on the message exchange and returns true if this exchange matches the predicate
XPathBuilder	namespace(String prefix, String uri) Registers the namespace prefix and URI with the builder so that the prefix can be used in XPath expressions
XPathBuilder	namespaces(Namespaces namespaces) Registers namespaces with the builder so that the registered prefixes can be used in XPath expressions
XPathBuilder	nodeResult() Sets the expression result type to boolean
XPathBuilder	nodeSetResult() Sets the expression result type to boolean
XPathBuilder	numberResult() Sets the expression result type to boolean
XPathBuilder	objectModel(String uri) Sets the object model URI to use
protected void	populateDefaultNamespaces(DefaultNamespaceContext context) Populate a number of standard prefixes if they are not already there
XPathBuilder	resultType(Class<?> resultType) Sets the expression result type to boolean
XPathBuilder	saxon() Configures to use Saxon as the XPathFactory which allows you to use XPath 2.0 functions which may not be part of the build in JDK XPath parser.
void	setBodyFunction(XPathFunction bodyFunction)
void	setDocumentType(Class<?> documentType)
void	setFunctionResolver(XPathFunctionResolver functionResolver)
void	setHeaderFunction(XPathFunction headerFunction)
void	setLogNamespaces(boolean logNamespaces)
void	setNamespaceContext(DefaultNamespaceContext namespaceContext)
protected void	setNamespaceIfNotPresent(DefaultNamespaceContext context, String prefix, String uri)
void	setNamespaces(Map<String,String> namespaces) Injects the XML Namespaces of prefix -> uri mappings
void	setObjectModelUri(String objectModelUri)
void	setOutBodyFunction(XPathFunction outBodyFunction)
void	setOutHeaderFunction(XPathFunction outHeaderFunction)
void	setPropertiesFunction(XPathFunction propertiesFunction)
void	setResultQName(QName resultQName)
void	setResultType(Class<?> resultType)
void	setSimpleFunction(XPathFunction simpleFunction)
void	setXPathFactory(XPathFactory xpathFactory)
XPathBuilder	stringResult() Sets the expression result type to boolean
String	toString()
XPathBuilder	variable(String name, Object value) Registers a variable (in the global namespace) which can be referred to from XPath expressions
static XPathBuilder	xpath(String text)
static XPathBuilder	xpath(String text, Class<?> resultType)

Methods inherited from class org.apache.camel.support.ServiceSupport

doResume, doShutdown, doSuspend, getStatus, getVersion, isRunAllowed, isStarted, isStarting, isStopped, isStopping, isSuspended, isSuspending, resume, shutdown, start, stop, suspend

Methods inherited from class java.lang.Object

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

Constructor Detail

XPathBuilder

public XPathBuilder(String text)

Parameters:

text - The XPath expression

Method Detail

xpath

public static XPathBuilder xpath(String text)

xpath

public static XPathBuilder xpath(String text,
                                 Class<?> resultType)

toString

public String toString()

Overrides:

toString in class Object

matches

public boolean matches(Exchange exchange)

Description copied from interface: Predicate

Evaluates the predicate on the message exchange and returns true if this exchange matches the predicate

Specified by:

matches in interface Predicate

Parameters:

exchange - the message exchange

Returns:

true if the predicate matches

evaluate

public <T> T evaluate(Exchange exchange,
                      Class<T> type)

Description copied from interface: Expression

Returns the value of the expression on the given exchange

Specified by:

evaluate in interface Expression

Parameters:

exchange - the message exchange on which to evaluate the expression

type - the expected type of the evaluation result

Returns:

the value of the expression

matches

public boolean matches(CamelContext context,
                       Object body)

Matches the given xpath using the provided body.

Parameters:

context - the camel context

body - the body

Returns:

true if matches, false otherwise

evaluate

public <T> T evaluate(CamelContext context,
                      Object body,
                      Class<T> type)

Evaluates the given xpath using the provided body.

Parameters:

context - the camel context

body - the body

type - the type to return

Returns:

result of the evaluation

evaluate

public String evaluate(CamelContext context,
                       Object body)

Evaluates the given xpath using the provided body as a String return type.

Parameters:

context - the camel context

body - the body

Returns:

result of the evaluation

booleanResult

public XPathBuilder booleanResult()

Sets the expression result type to boolean

Returns:

the current builder

nodeResult

public XPathBuilder nodeResult()

Sets the expression result type to boolean

Returns:

the current builder

nodeSetResult

public XPathBuilder nodeSetResult()

Sets the expression result type to boolean

Returns:

the current builder

numberResult

public XPathBuilder numberResult()

Sets the expression result type to boolean

Returns:

the current builder

stringResult

public XPathBuilder stringResult()

Sets the expression result type to boolean

Returns:

the current builder

resultType

public XPathBuilder resultType(Class<?> resultType)

Sets the expression result type to boolean

Returns:

the current builder

objectModel

public XPathBuilder objectModel(String uri)

Sets the object model URI to use

Returns:

the current builder

saxon

public XPathBuilder saxon()

Configures to use Saxon as the XPathFactory which allows you to use XPath 2.0 functions which may not be part of the build in JDK XPath parser.

Returns:

the current builder

functionResolver

public XPathBuilder functionResolver(XPathFunctionResolver functionResolver)

Sets the XPathFunctionResolver instance to use on these XPath expressions

Returns:

the current builder

namespace

public XPathBuilder namespace(String prefix,
                              String uri)

Registers the namespace prefix and URI with the builder so that the prefix can be used in XPath expressions

Parameters:

prefix - is the namespace prefix that can be used in the XPath expressions

uri - is the namespace URI to which the prefix refers

Returns:

the current builder

namespaces

public XPathBuilder namespaces(Namespaces namespaces)

Registers namespaces with the builder so that the registered prefixes can be used in XPath expressions

Parameters:

namespaces - is namespaces object that should be used in the XPath expression

Returns:

the current builder

variable

public XPathBuilder variable(String name,
                             Object value)

Registers a variable (in the global namespace) which can be referred to from XPath expressions

Parameters:

name - name of variable

value - value of variable

Returns:

the current builder

documentType

public XPathBuilder documentType(Class<?> documentType)

Configures the document type to use.

The document type controls which kind of Class Camel should convert the payload to before doing the xpath evaluation.

For example you can set it to InputSource to use SAX streams. By default Camel uses Document as the type.

Parameters:

documentType - the document type

Returns:

the current builder

factory

public XPathBuilder factory(XPathFactory xpathFactory)

Configures to use the provided XPath factory.

Can be used to use Saxon instead of the build in factory from the JDK.

Parameters:

xpathFactory - the xpath factory to use

Returns:

the current builder.

logNamespaces

public XPathBuilder logNamespaces()

Activates trace logging of all discovered namespaces in the message - to simplify debugging namespace-related issues

Namespaces are printed in Hashmap style {xmlns:prefix=[namespaceURI], xmlns:prefix=[namespaceURI]}.

The implicit XML namespace is omitted (http://www.w3.org/XML/1998/namespace). XML allows for namespace prefixes to be redefined/overridden due to hierarchical scoping, i.e. prefix abc can be mapped to http://abc.com, and deeper in the document it can be mapped to http://def.com. When two prefixes are detected which are equal but are mapped to different namespace URIs, Camel will show all namespaces URIs it is mapped to in an array-style.

This feature is disabled by default.

Returns:

the current builder.

getXPathFactory

public XPathFactory getXPathFactory()

Gets the xpath factory, can be null if no custom factory has been assigned.

A default factory will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the factory, or null if this builder has not been started/used before.

setXPathFactory

public void setXPathFactory(XPathFactory xpathFactory)

getDocumentType

public Class<?> getDocumentType()

setDocumentType

public void setDocumentType(Class<?> documentType)

getText

public String getText()

getResultQName

public QName getResultQName()

setResultQName

public void setResultQName(QName resultQName)

getNamespaceContext

public DefaultNamespaceContext getNamespaceContext()

Gets the namespace context, can be null if no custom context has been assigned.

A default context will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the context, or null if this builder has not been started/used before.

setNamespaceContext

public void setNamespaceContext(DefaultNamespaceContext namespaceContext)

getFunctionResolver

public XPathFunctionResolver getFunctionResolver()

setFunctionResolver

public void setFunctionResolver(XPathFunctionResolver functionResolver)

setNamespaces

public void setNamespaces(Map<String,String> namespaces)

Description copied from interface: NamespaceAware

Injects the XML Namespaces of prefix -> uri mappings

Specified by:

setNamespaces in interface NamespaceAware

Parameters:

namespaces - the XML namespaces with the key of prefixes and the value the URIs

getBodyFunction

public XPathFunction getBodyFunction()

Gets the XPathFunction for getting the input message body.

A default function will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the function, or null if this builder has not been started/used before.

setBodyFunction

public void setBodyFunction(XPathFunction bodyFunction)

getHeaderFunction

public XPathFunction getHeaderFunction()

Gets the XPathFunction for getting the input message header.

A default function will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the function, or null if this builder has not been started/used before.

setHeaderFunction

public void setHeaderFunction(XPathFunction headerFunction)

getOutBodyFunction

public XPathFunction getOutBodyFunction()

Gets the XPathFunction for getting the output message body.

A default function will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the function, or null if this builder has not been started/used before.

setOutBodyFunction

public void setOutBodyFunction(XPathFunction outBodyFunction)

getOutHeaderFunction

public XPathFunction getOutHeaderFunction()

Gets the XPathFunction for getting the output message header.

A default function will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the function, or null if this builder has not been started/used before.

setOutHeaderFunction

public void setOutHeaderFunction(XPathFunction outHeaderFunction)

getPropertiesFunction

public XPathFunction getPropertiesFunction()

Gets the XPathFunction for getting the exchange properties.

A default function will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the function, or null if this builder has not been started/used before.

setPropertiesFunction

public void setPropertiesFunction(XPathFunction propertiesFunction)

getSimpleFunction

public XPathFunction getSimpleFunction()

Gets the XPathFunction for executing simple language as xpath function.

A default function will be assigned (if no custom assigned) when either starting this builder or on first evaluation.

Returns:

the function, or null if this builder has not been started/used before.

setSimpleFunction

public void setSimpleFunction(XPathFunction simpleFunction)

getResultType

public Class<?> getResultType()

setResultType

public void setResultType(Class<?> resultType)

setLogNamespaces

public void setLogNamespaces(boolean logNamespaces)

isLogNamespaces

public boolean isLogNamespaces()

getObjectModelUri

public String getObjectModelUri()

enableSaxon

public void enableSaxon()

Enables Saxon on this particular XPath expression, as saxon() sets the default static XPathFactory which may have already been initialised by previous XPath expressions

setObjectModelUri

public void setObjectModelUri(String objectModelUri)

evaluate

protected Object evaluate(Exchange exchange)

evaluateAs

protected Object evaluateAs(Exchange exchange,
                            QName resultQName)

Evaluates the expression as the given result type

doInEvaluateAs

protected Object doInEvaluateAs(XPathExpression xpathExpression,
                                Exchange exchange,
                                QName resultQName)

createXPathExpression

protected XPathExpression createXPathExpression()
                                         throws XPathExpressionException,
                                                XPathFactoryConfigurationException

Creates a new xpath expression as there we no available in the pool.

This implementation must be synchronized to ensure thread safety, as this XPathBuilder instance may not have been started prior to being used.

Throws:

XPathExpressionException

XPathFactoryConfigurationException

createTraceNamespaceExpression

protected XPathExpression createTraceNamespaceExpression()
                                                  throws XPathFactoryConfigurationException,
                                                         XPathExpressionException

Throws:

XPathFactoryConfigurationException

XPathExpressionException

createNamespaceContext

protected DefaultNamespaceContext createNamespaceContext(XPathFactory factory)

populateDefaultNamespaces

protected void populateDefaultNamespaces(DefaultNamespaceContext context)

Populate a number of standard prefixes if they are not already there

setNamespaceIfNotPresent

protected void setNamespaceIfNotPresent(DefaultNamespaceContext context,
                                        String prefix,
                                        String uri)

createDefaultFunctionResolver

protected XPathFunctionResolver createDefaultFunctionResolver(XPathFunctionResolver parent)

isInputStreamNeeded

protected boolean isInputStreamNeeded(Exchange exchange)

Checks whether we need an InputStream to access the message body.

Depending on the content in the message body, we may not need to convert to InputStream.

Parameters:

exchange - the current exchange

Returns:

true to convert to InputStream beforehand converting afterwards.

getDocument

protected Object getDocument(Exchange exchange,
                             Object body)

Strategy method to extract the document from the exchange.

doGetDocument

protected Object doGetDocument(Exchange exchange,
                               Object body)
                        throws Exception

Throws:

Exception

doStart

public void doStart()
             throws Exception

Description copied from class: ServiceSupport

Implementations override this method to support customized start/stop.

Important: See ServiceSupport.doStop() for more details.

Specified by:

doStart in class ServiceSupport

Throws:

Exception

See Also:

ServiceSupport.doStop()

doStop

public void doStop()
            throws Exception

Description copied from class: ServiceSupport

Implementations override this method to support customized start/stop.

Important: Camel will invoke this ServiceSupport.doStop() method when the service is being stopped. This method will also be invoked if the service is still in uninitialized state (eg has not been started). The method is always called to allow the service to do custom logic when the service is being stopped, such as when CamelContext is shutting down.

Specified by:

doStop in class ServiceSupport

Throws:

Exception

See Also:

ServiceSupport.doStart()

createXPathFactory

protected XPathFactory createXPathFactory()
                                   throws XPathFactoryConfigurationException

Throws:

XPathFactoryConfigurationException

initDefaultXPathFactory

protected void initDefaultXPathFactory()
                                throws XPathFactoryConfigurationException

Throws:

XPathFactoryConfigurationException