org.mule.api.expression
Interface ExpressionManager

All Known Implementing Classes:

DefaultExpressionManager

public interface ExpressionManager

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

static String	DEFAULT_EXPRESSION_POSTFIX
static String	DEFAULT_EXPRESSION_PREFIX

Method Summary

void	clearEvaluators() Clears all registered evaluators from the manager.
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	isEvaluatorRegistered(String name) Checks whether an evaluator is registered with the manager
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	registerEvaluator(ExpressionEvaluator evaluator)
ExpressionEvaluator	unregisterEvaluator(String name) Removes the evaluator with the given name

Field Detail

DEFAULT_EXPRESSION_PREFIX

static final String DEFAULT_EXPRESSION_PREFIX

See Also:

Constant Field Values

DEFAULT_EXPRESSION_POSTFIX

static final String DEFAULT_EXPRESSION_POSTFIX

See Also:

Constant Field Values

Method Detail

registerEvaluator

void registerEvaluator(ExpressionEvaluator evaluator)

isEvaluatorRegistered

boolean isEvaluatorRegistered(String name)

Checks whether an evaluator is registered with the manager

Parameters:

name - the name of the expression evaluator

Returns:

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

unregisterEvaluator

ExpressionEvaluator unregisterEvaluator(String name)

Removes the evaluator with the given name

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

evaluate

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 parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

Parameters:

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

message - The current message being processed

Returns:

the result of the evaluation

Throws:

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

evaluate

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 parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

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

Throws:

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

evaluate

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 parse(String,org.mule.api.MuleMessage,boolean) method should be used since it will iterate through all expressions in a string.

Parameters:

expression - one or more expressions ebedded 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 bing processed

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

Throws:

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

parse

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 evaluate(String,org.mule.api.MuleMessage,boolean).

Parameters:

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

message - The current message being processed

Returns:

the result of the evaluation

Throws:

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

parse

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 evaluate(String,org.mule.api.MuleMessage,boolean).

Parameters:

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

Throws:

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

clearEvaluators

void clearEvaluators()

Clears all registered evaluators from the manager.

isValidExpression

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]

Parameters:

expression - the expression to validate

Returns:

true if the expression evaluator is recognised