org.mule.expression
Class DefaultExpressionManager

java.lang.Object
  org.mule.expression.DefaultExpressionManager

All Implemented Interfaces:

MuleContextAware, ExpressionManager

public class DefaultExpressionManager
extends Object
implements ExpressionManager, MuleContextAware

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

protected static Log

logger logger used by this class

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

DEFAULT_EXPRESSION_POSTFIX, DEFAULT_EXPRESSION_PREFIX

Constructor Summary

DefaultExpressionManager()

Method Summary

void	clearEnrichers() Clears all registered enrichers from the manager.
void	clearEvaluators() Clears all registered evaluators from the manager.
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
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, 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.
boolean	isEnricherRegistered(String name) Checks whether an enricher is registered with the manager
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, 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)
protected boolean	resolveBoolean(Object result, boolean nullReturnsTrue, boolean nonBooleanReturnsTrue, String expression)
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 Log logger

logger used by this class

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. "mule:serviceName" and "#[mule: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,
                       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. "mule:serviceName" and "#[mule: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.

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 shoud 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

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. "mule:serviceName" and "#[mule: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.

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. "mule:serviceName" and "#[mule: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. "mule:serviceName" and "#[mule: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. "mule:serviceName" and "#[mule: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. "mule:serviceName" and "#[mule: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

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,
                    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.

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

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 be well formed i.e. #[bean:user]

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