com.neurosys.etl.common.transformers

Class SpELTransformer

java.lang.Object

com.neurosys.etl.common.transformers.SpELTransformer

All Implemented Interfaces:

FunctionTransformer, Function, org.apache.commons.collections.Transformer, org.springframework.beans.factory.Aware, org.springframework.context.ApplicationContextAware

public class SpELTransformer
extends Object
implements FunctionTransformer, org.springframework.context.ApplicationContextAware

Spring SpEL Transformer that evaluates a given the input or context. If the input is null it defaults to the context and visa-versa
It also calls expressionTest() is testExpression is true and additionally caches expressionInstance for recurring evaluation as the expression or configuration is unlikely to change. If you do not want it cached and re-construct the expression from configuration on each call then set cacheExpression to false.

If ignoreInput is false, then the input is considered as the context to which the SpEL properties are resolved. Example: Map. See Expression.getValue(Object). One can refer to root as #root and this as #this. In the bean def. these result in BeanExpressionContext objects.

Sample Code config:

         <!-- Auto Index & cache clear -->
        getBean("contentFacetSearch").index()
        getBean("cacheManager").getCache("#{T(com.neurosys.lookups.CacheLookups).CONTENT_PUBLISH_CACHE_NAME}").clear()
 

Author:

Arjun Dhar

See Also:

TODO: Add unit test case

Constructor Summary

Constructors

Constructor and Description
SpELTransformer()
SpELTransformer(String expression)

Method Summary

Modifier and Type	Method and Description
protected org.springframework.expression.Expression	deriveExpression()
org.springframework.expression.spel.SpelParserConfiguration	getConfiguration()
org.springframework.expression.spel.support.StandardEvaluationContext	getContext() Default context supplied to the ExpressionParser
String	getExpression() The expression to parse against
Class	getReturnType() The expected return type of the expression
boolean	isCacheExpression() If true will use expressionInstanceto cache the Expression for frequent use.
boolean	isIgnoreInput() If true it will only consider context as input to the Expression parser
boolean	isTestExpression() If true will self test expression on startup.
void	setApplicationContext(org.springframework.context.ApplicationContext applicationContext)
void	setCacheExpression(boolean cacheExpression) If true will use expressionInstanceto cache the Expression for frequent use.
void	setConfiguration(org.springframework.expression.spel.SpelParserConfiguration configuration)
void	setContext(org.springframework.expression.spel.support.StandardEvaluationContext context) Default context supplied to the ExpressionParser
void	setExpression(String expression) The expression to parse against
void	setIgnoreInput(boolean ignoreInput) If true it will only consider context as input to the Expression parser
void	setReturnType(Class returnType) The expected return type of the expression
void	setTestExpression(boolean testExpression) If true will self test expression on startup.
Object	transform(Object input)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.neurosys.etl.common.transformers.FunctionTransformer

apply

Methods inherited from interface java.util.function.Function

andThen, compose, identity

Constructor Detail

SpELTransformer

public SpELTransformer()

SpELTransformer

public SpELTransformer(String expression)

Method Detail

deriveExpression

protected org.springframework.expression.Expression deriveExpression()

transform

public Object transform(Object input)

Specified by:

transform in interface org.apache.commons.collections.Transformer

setApplicationContext

public void setApplicationContext(org.springframework.context.ApplicationContext applicationContext)
                           throws org.springframework.beans.BeansException

Specified by:

setApplicationContext in interface org.springframework.context.ApplicationContextAware

Throws:

org.springframework.beans.BeansException

getContext

public org.springframework.expression.spel.support.StandardEvaluationContext getContext()

Default context supplied to the ExpressionParser

Can be null:

true , if null the Spring context is supplied if the bean was defined in one.

setContext

public void setContext(org.springframework.expression.spel.support.StandardEvaluationContext context)

Default context supplied to the ExpressionParser

Can be null:

true , if null the Spring context is supplied if the bean was defined in one.

getReturnType

public Class getReturnType()

The expected return type of the expression

setReturnType

public void setReturnType(Class returnType)

The expected return type of the expression

getConfiguration

public org.springframework.expression.spel.SpelParserConfiguration getConfiguration()

Can be null:

true

setConfiguration

public void setConfiguration(org.springframework.expression.spel.SpelParserConfiguration configuration)

Can be null:

true

getExpression

public String getExpression()

The expression to parse against

setExpression

public void setExpression(String expression)

The expression to parse against

isIgnoreInput

public boolean isIgnoreInput()

If true it will only consider context as input to the Expression parser

Default value:

false

setIgnoreInput

public void setIgnoreInput(boolean ignoreInput)

If true it will only consider context as input to the Expression parser

Default value:

false

isTestExpression

public boolean isTestExpression()

If true will self test expression on startup.

Default value:

true

setTestExpression

public void setTestExpression(boolean testExpression)

If true will self test expression on startup.

Default value:

true

isCacheExpression

public boolean isCacheExpression()

If true will use expressionInstanceto cache the Expression for frequent use.

Default value:

true

setCacheExpression

public void setCacheExpression(boolean cacheExpression)

If true will use expressionInstanceto cache the Expression for frequent use.

Default value:

true