org.mule.expression

Class DefaultExpressionManager

java.lang.Object

org.mule.expression.DefaultExpressionManager

All Implemented Interfaces:

MuleContextAware, ExpressionManager, Initialisable

public class DefaultExpressionManager
extends Object
implements ExpressionManager, MuleContextAware, Initialisable

Provides universal access for evaluating expressions embedded in Mule configurations, such as Xml, Java, scripting and annotations.

Users can register or unregister ExpressionEvaluator through this interface.

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.apache.commons.logging.Log	logger logger used by this class
static String	OBJECT_FOR_ENRICHMENT

Fields inherited from interface org.mule.api.expression.ExpressionManager

DEFAULT_EXPRESSION_POSTFIX, DEFAULT_EXPRESSION_PREFIX

Fields inherited from interface org.mule.api.lifecycle.Initialisable

PHASE_NAME

Constructor Summary

Constructors

Constructor and Description
DefaultExpressionManager()

Method Summary

Methods

Modifier and Type	Method and Description
void	clearEnrichers() Clears all registered enrichers from the manager.
void	clearEvaluators() Clears all registered evaluators from the manager.
protected String	createEnrichmentExpression(String expression)
void	enrich(String expression, MuleEvent event, Object object)
void	enrich(String expression, MuleMessage message, Object object) Enriches the current message using
void	enrich(String expression, String enricherName, MuleMessage message, Object object) Enriches the current message
void	enrichTyped(String expression, MuleMessage message, TypedValue object) Enriches the current message using a typed value
Object	evaluate(String expression, MuleEvent event)
Object	evaluate(String expression, MuleEvent event, boolean failIfNull) Evaluates the given expression.
Object	evaluate(String expression, MuleMessage message) Evaluates the given expression.
Object	evaluate(String expression, MuleMessage message, boolean failIfNull) Evaluates the given expression.
Object	evaluate(String expression, String evaluator, MuleMessage message, boolean failIfNull) Evaluates the given expression.
boolean	evaluateBoolean(String expression, MuleEvent event)
boolean	evaluateBoolean(String expression, MuleEvent event, boolean nullReturnsTrue, boolean nonBooleanReturnsTrue)
boolean	evaluateBoolean(String expression, MuleMessage message) Evaluates the given expression resolving the result of the evaluation to a boolean.
boolean	evaluateBoolean(String expression, MuleMessage message, boolean nullReturnsTrue, boolean nonBooleanReturnsTrue) Evaluates the given expression resolving the result of the evaluation to a boolean.
boolean	evaluateBoolean(String expression, String evaluator, MuleMessage message) Evaluates the given expression resolving the result of the evaluation to a boolean.
boolean	evaluateBoolean(String expression, String evaluator, MuleMessage message, boolean nullReturnsTrue, boolean nonBooleanReturnsTrue) Evaluates the given expression resolving the result of the evaluation to a boolean.
TypedValue	evaluateTyped(String expression, MuleMessage message)
TypedValue	evaluateTyped(String expression, String evaluator, MuleMessage message, boolean failIfNull) Evaluates the given expression propagating dataType.
ExpressionLanguage	getExpressionLanguage()
void	initialise() Method used to perform any initialisation work.
protected boolean	isEnricherExpression(String expression)
boolean	isEnricherRegistered(String name) Checks whether an enricher is registered with the manager
protected boolean	isEvaluatorExpression(String expression)
boolean	isEvaluatorRegistered(String name) Checks whether an evaluator is registered with the manager
boolean	isExpression(String string) Determines if the string is an expression.
boolean	isValidExpression(String expression) Determines if the expression is valid or not.
String	parse(String expression, MuleEvent event)
String	parse(String expression, MuleEvent event, boolean failIfNull)
String	parse(String expression, MuleMessage message) Evaluates expressions in a given string.
String	parse(String expression, MuleMessage message, boolean failIfNull) Evaluates expressions in a given string.
void	registerEnricher(ExpressionEnricher enricher)
void	registerEvaluator(ExpressionEvaluator evaluator)
static String	removeExpressionMarker(String expression)
protected boolean	resolveBoolean(Object result, boolean nullReturnsTrue, boolean nonBooleanReturnsTrue, String expression)
void	setExpressionLanguage(ExpressionLanguage expressionLanguage)
void	setMuleContext(MuleContext context)
ExpressionEnricher	unregisterEnricher(String name) Removes the evaluator with the given name
ExpressionEvaluator	unregisterEvaluator(String name) Removes the evaluator with the given name
void	validateExpression(String expression) Determines if the expression is valid or not.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final transient org.apache.commons.logging.Log logger

logger used by this class

OBJECT_FOR_ENRICHMENT

public static final String OBJECT_FOR_ENRICHMENT

See Also:

Constant Field Values

Constructor Detail

DefaultExpressionManager

public DefaultExpressionManager()

Method Detail

setMuleContext

public void setMuleContext(MuleContext context)

Specified by:

setMuleContext in interface MuleContextAware

registerEvaluator

public void registerEvaluator(ExpressionEvaluator evaluator)

Specified by:

registerEvaluator in interface ExpressionManager

registerEnricher

public void registerEnricher(ExpressionEnricher enricher)

Specified by:

registerEnricher in interface ExpressionManager

isEvaluatorRegistered

public boolean isEvaluatorRegistered(String name)

Checks whether an evaluator is registered with the manager

Specified by:

isEvaluatorRegistered in interface ExpressionManager

Parameters:

name - the name of the expression evaluator

Returns:

true if the evaluator is registered with the manager, false otherwise

isEnricherRegistered

public boolean isEnricherRegistered(String name)

Checks whether an enricher is registered with the manager

Specified by:

isEnricherRegistered in interface ExpressionManager

Parameters:

name - the name of the expression enricher

Returns:

true if the enricher is registered with the manager, false otherwise

unregisterEvaluator

public ExpressionEvaluator unregisterEvaluator(String name)

Removes the evaluator with the given name

Specified by:

unregisterEvaluator in interface ExpressionManager

Parameters:

name - the name of the evaluator to remove

Returns:

the evaluator that was removed. This will be null if the evaluator was not registered

unregisterEnricher

public ExpressionEnricher unregisterEnricher(String name)

Removes the evaluator with the given name

Specified by:

unregisterEnricher in interface ExpressionManager

Parameters:

name - the name of the evaluator to remove

Returns:

the enricher that was removed. This will be null if the enricher was not registered

evaluate

public Object evaluate(String expression,
              MuleMessage message)
                throws ExpressionRuntimeException

Evaluates the given expression. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid. For situations where one or more expressions need to be parsed within a single text, the ExpressionManager.parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

Specified by:

evaluate in interface ExpressionManager

Parameters:

expression - a single expression i.e. xpath://foo

message - the current message to process. The expression will evaluata on the message.

Returns:

the result of the evaluation. Expressions that return collection will return an empty collection, not null.

Throws:

ExpressionRuntimeException - if the expression is invalid, or a null is found for the expression and 'failIfNull is set to true.

evaluate

public Object evaluate(String expression,
              MuleEvent event)
                throws ExpressionRuntimeException

Specified by:

evaluate in interface ExpressionManager

Throws:

ExpressionRuntimeException

evaluate

public Object evaluate(String expression,
              MuleEvent event,
              boolean failIfNull)
                throws ExpressionRuntimeException

Evaluates the given expression. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid. For situations where one or more expressions need to be parsed within a single text, the ExpressionManager.parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

Specified by:

evaluate in interface ExpressionManager

Parameters:

expression - a single expression i.e. xpath://foo

message - the current message to process. The expression will evaluata on the message.

failIfNull - determines if an exception should be thrown if expression could not be evaluated or returns null.

Returns:

the result of the evaluation. Expressions that return collection will return an empty collection, not null.

Throws:

ExpressionRuntimeException - if the expression is invalid, or a null is found for the expression and 'failIfNull is set to true.

evaluate

public Object evaluate(String expression,
              MuleMessage message,
              boolean failIfNull)

Description copied from interface: ExpressionManager

Evaluates the given expression. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid. For situations where one or more expressions need to be parsed within a single text, the ExpressionManager.parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

Specified by:

evaluate in interface ExpressionManager

Parameters:

expression - a single expression i.e. xpath://foo

message - The current message being processed

failIfNull - determines if an exception should be thrown if expression could not be evaluated or returns null. @return the result of the evaluation

Returns:

the parsered expression string

enrich

public void enrich(String expression,
          MuleMessage message,
          Object object)
            throws ExpressionRuntimeException

Description copied from interface: ExpressionManager

Enriches the current message using

Specified by:

enrich in interface ExpressionManager

Parameters:

expression - a single expression i.e. header://foo that defines how the message should be enriched

message - The current message being processed that will be enriched

object - The object that will be used to enrich the message

Throws:

ExpressionRuntimeException

enrichTyped

public void enrichTyped(String expression,
               MuleMessage message,
               TypedValue object)

Description copied from interface: ExpressionManager

Enriches the current message using a typed value

Specified by:

enrichTyped in interface ExpressionManager

Parameters:

expression - a single expression i.e. header://foo that defines how the message should be enriched

message - The current message being processed that will be enriched

object - The typed value that will be used to enrich the message

enrich

public void enrich(String expression,
          MuleEvent event,
          Object object)

Specified by:

enrich in interface ExpressionManager

enrich

public void enrich(String expression,
          String enricherName,
          MuleMessage message,
          Object object)

Description copied from interface: ExpressionManager

Enriches the current message

Specified by:

enrich in interface ExpressionManager

Parameters:

expression - a single expression i.e. header://foo that defines how the message shoud be enriched

enricherName - the enricher to use when executing the expression

message - The current message being processed that will be enriched

object - The object that will be used to enrich the message

evaluate

public Object evaluate(String expression,
              String evaluator,
              MuleMessage message,
              boolean failIfNull)
                throws ExpressionRuntimeException

Evaluates the given expression. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid. For situations where one or more expressions need to be parsed within a single text, the ExpressionManager.parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

Specified by:

evaluate in interface ExpressionManager

Parameters:

expression - a single expression i.e. xpath://foo

evaluator - the evaluator to use when executing the expression

message - the current message to process. The expression will evaluata on the message.

failIfNull - determines if an exception should be thrown if expression could not be evaluated or returns null or if an exception should be thrown if an empty collection is returned.

Returns:

the result of the evaluation. Expressions that return collection will return an empty collection, not null.

Throws:

ExpressionRuntimeException - if the expression is invalid, or a null is found for the expression and 'failIfNull is set to true.

evaluateTyped

public TypedValue evaluateTyped(String expression,
                       String evaluator,
                       MuleMessage message,
                       boolean failIfNull)
                         throws ExpressionRuntimeException

Description copied from interface: ExpressionManager

Evaluates the given expression propagating dataType.

The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid. For situations where one or more expressions need to be parsed within a single text, the ExpressionManager.parse(String, org.mule.api.MuleMessage, boolean) method should be used since it will iterate through all expressions in a string.

Specified by:

evaluateTyped in interface ExpressionManager

Parameters:

expression - one or more expressions embedded in a literal string i.e. "Value is #[xpath://foo] other value is #[header:foo]."

evaluator - the evaluator to use when executing the expression

message - The current message being processed

failIfNull - determines if an exception should be thrown if expression could not be evaluated or returns null. @return the result of the evaluation

Returns:

the result of evalauting the expression with the corresponding dataType

Throws:

ExpressionRuntimeException - if the expression is invalid, or a null is found for the expression and 'failIfNull is set to true.

evaluateBoolean

public boolean evaluateBoolean(String expression,
                      String evaluator,
                      MuleMessage message)
                        throws ExpressionRuntimeException

Description copied from interface: ExpressionManager

Evaluates the given expression resolving the result of the evaluation to a boolean. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid.

Specified by:

evaluateBoolean in interface ExpressionManager

Parameters:

expression - a single expression i.e. header:foo=bar

evaluator - the evaluator to use when executing the expression

message - The current message being processed

Throws:

ExpressionRuntimeException

evaluateBoolean

public boolean evaluateBoolean(String expression,
                      MuleMessage message)
                        throws ExpressionRuntimeException

Description copied from interface: ExpressionManager

Evaluates the given expression resolving the result of the evaluation to a boolean. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid.

Specified by:

evaluateBoolean in interface ExpressionManager

Parameters:

expression - a single expression i.e. header:foo=bar

message - The current message being processed

Throws:

ExpressionRuntimeException

evaluateBoolean

public boolean evaluateBoolean(String expression,
                      String evaluator,
                      MuleMessage message,
                      boolean nullReturnsTrue,
                      boolean nonBooleanReturnsTrue)
                        throws ExpressionRuntimeException

Description copied from interface: ExpressionManager

Evaluates the given expression resolving the result of the evaluation to a boolean. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid.

Specified by:

evaluateBoolean in interface ExpressionManager

Parameters:

expression - a single expression i.e. header:foo=bar

evaluator - the evaluator to use when executing the expression

message - The current message being processed

nullReturnsTrue - determines if true should be returned if the result of the evaluation is null

nonBooleanReturnsTrue - determines if true should returned if the result is not null but isn't recognised as a boolean

Throws:

ExpressionRuntimeException

evaluateBoolean

public boolean evaluateBoolean(String expression,
                      MuleMessage message,
                      boolean nullReturnsTrue,
                      boolean nonBooleanReturnsTrue)
                        throws ExpressionRuntimeException

Description copied from interface: ExpressionManager

Evaluates the given expression resolving the result of the evaluation to a boolean. The expression should be a single expression definition with or without enclosing braces. i.e. "context:serviceName" and "#[context:serviceName]" are both valid.

Specified by:

evaluateBoolean in interface ExpressionManager

Parameters:

expression - a single expression i.e. header:foo=bar

message - The current message being processed

nullReturnsTrue - determines if true should be returned if the result of the evaluation is null

nonBooleanReturnsTrue - determines if true should returned if the result is not null but isn't recognised as a boolean

Throws:

ExpressionRuntimeException

evaluateBoolean

public boolean evaluateBoolean(String expression,
                      MuleEvent event,
                      boolean nullReturnsTrue,
                      boolean nonBooleanReturnsTrue)
                        throws ExpressionRuntimeException

Specified by:

evaluateBoolean in interface ExpressionManager

Throws:

ExpressionRuntimeException

resolveBoolean

protected boolean resolveBoolean(Object result,
                     boolean nullReturnsTrue,
                     boolean nonBooleanReturnsTrue,
                     String expression)

parse

public String parse(String expression,
           MuleMessage message)
             throws ExpressionRuntimeException

Evaluates expressions in a given string. This method will iterate through each expression and evaluate it. If a user needs to evaluate a single expression they can use ExpressionManager.evaluate(String,org.mule.api.MuleMessage,boolean).

Specified by:

parse in interface ExpressionManager

Parameters:

expression - a single expression i.e. xpath://foo

message - the current message to process. The expression will evaluata on the message.

Returns:

the result of the evaluation. Expressions that return collection will return an empty collection, not null.

Throws:

ExpressionRuntimeException - if the expression is invalid, or a null is found for the expression and 'failIfNull is set to true.

parse

public String parse(String expression,
           MuleEvent event)
             throws ExpressionRuntimeException

Specified by:

parse in interface ExpressionManager

Throws:

ExpressionRuntimeException

parse

public String parse(String expression,
           MuleMessage message,
           boolean failIfNull)
             throws ExpressionRuntimeException

Evaluates expressions in a given string. This method will iterate through each expression and evaluate it. If a user needs to evaluate a single expression they can use ExpressionManager.evaluate(String,org.mule.api.MuleMessage,boolean).

Specified by:

parse in interface ExpressionManager

Parameters:

expression - a single expression i.e. xpath://foo

message - the current message to process. The expression will evaluata on the message.

failIfNull - determines if an exception should be thrown if expression could not be evaluated or returns null.

Returns:

the result of the evaluation. Expressions that return collection will return an empty collection, not null.

Throws:

ExpressionRuntimeException - if the expression is invalid, or a null is found for the expression and 'failIfNull is set to true.

parse

public String parse(String expression,
           MuleEvent event,
           boolean failIfNull)
             throws ExpressionRuntimeException

Specified by:

parse in interface ExpressionManager

Throws:

ExpressionRuntimeException

clearEvaluators

public void clearEvaluators()

Clears all registered evaluators from the manager.

Specified by:

clearEvaluators in interface ExpressionManager

clearEnrichers

public void clearEnrichers()

Description copied from interface: ExpressionManager

Clears all registered enrichers from the manager.

Specified by:

clearEnrichers in interface ExpressionManager

isExpression

public boolean isExpression(String string)

Description copied from interface: ExpressionManager

Determines if the string is an expression. This method will validate that the string contains either the expression prefix (malformed) or a full expression. This isn't full proof but catches most error cases

Specified by:

isExpression in interface ExpressionManager

Parameters:

string - is this string an expression string

Returns:

true if the string contains an expression

evaluateTyped

public TypedValue evaluateTyped(String expression,
                       MuleMessage message)

Specified by:

evaluateTyped in interface ExpressionManager

isValidExpression

public boolean isValidExpression(String expression)

Determines if the expression is valid or not. This method will validate a single expression or expressions embedded in a string. the expression must be well formed i.e. #[bean:user]

Specified by:

isValidExpression in interface ExpressionManager

Parameters:

expression - the expression to validate

Returns:

true if the expression evaluator is recognised

validateExpression

public void validateExpression(String expression)
                        throws InvalidExpressionException

Description copied from interface: ExpressionManager

Determines if the expression is valid or not. This method will validate a single expression or expressions embedded in a string. The expression must either be a well formed expression evaluator i.e. #[bean:user] or must be a valid expression language expression.

Specified by:

validateExpression in interface ExpressionManager

Parameters:

expression - the expression to validate

Throws:

InvalidExpressionException - if the expression is invalid, including information about the position and fault

initialise

public void initialise()
                throws InitialisationException

Description copied from interface: Initialisable

Method used to perform any initialisation work. If a fatal error occurs during initialisation an InitialisationException should be thrown, causing the Mule instance to shutdown. If the error is recoverable, say by retrying to connect, a RecoverableException should be thrown. There is no guarantee that by throwing a Recoverable exception that the Mule instance will not shut down.

Specified by:

initialise in interface Initialisable

Throws:

InitialisationException - if a fatal error occurs causing the Mule instance to shutdown

RecoverableException - if an error occurs that can be recovered from

evaluateBoolean

public boolean evaluateBoolean(String expression,
                      MuleEvent event)
                        throws ExpressionRuntimeException

Specified by:

evaluateBoolean in interface ExpressionManager

Throws:

ExpressionRuntimeException

removeExpressionMarker

public static String removeExpressionMarker(String expression)

isEvaluatorExpression

protected boolean isEvaluatorExpression(String expression)

isEnricherExpression

protected boolean isEnricherExpression(String expression)

createEnrichmentExpression

protected String createEnrichmentExpression(String expression)

setExpressionLanguage

public void setExpressionLanguage(ExpressionLanguage expressionLanguage)

getExpressionLanguage

public ExpressionLanguage getExpressionLanguage()