cascading.operation.assertion
Class AssertExpression

java.lang.Object
  cascading.operation.BaseOperation<ExpressionOperation.Context>
      cascading.operation.expression.ExpressionOperation
          cascading.operation.assertion.AssertExpression

All Implemented Interfaces:

Assertion<ExpressionOperation.Context>, Operation<ExpressionOperation.Context>, PlannedOperation<ExpressionOperation.Context>, ValueAssertion<ExpressionOperation.Context>, Serializable

public class AssertExpression
extends ExpressionOperation
implements ValueAssertion<ExpressionOperation.Context>

Class AssertExpression dynamically resolves a given expression using argument Tuple values. Any Tuple that returns true for the given expression pass the assertion. This Assertion is based on the Janino compiler.

Specifially this filter uses the ExpressionEvaluator, thus the syntax from that class is inherited here.

An expression may use field names directly as parameters in the expression, or field positions with the syntax "$n", where n is an integer.

Given an argument tuple with the fields "a" and "b", the following expression returns true:
a + b == $0 + $1

Further, the types of the tuple elements will be coerced into the given parameterTypes. Regardless of the actual tuple element values, they will be converted to the types expected by the expression.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class cascading.operation.expression.ExpressionOperation

ExpressionOperation.Context

Field Summary

Fields inherited from class cascading.operation.expression.ExpressionOperation

expression

Fields inherited from class cascading.operation.BaseOperation

fieldDeclaration, numArgs, trace

Fields inherited from interface cascading.operation.Operation

ANY

Constructor Summary

AssertExpression(Fields fieldDeclaration, String expression, String[] parameterNames, Class[] parameterTypes)
Constructor AssertExpression creates a new AssertExpression instance.

AssertExpression(String expression, Class parameterType)
Constructor ExpressionFilter creates a new ExpressionFilter instance.

Method Summary

void	doAssert(FlowProcess flowProcess, ValueAssertionCall<ExpressionOperation.Context> assertionCall) Method doAssert performs the assertion.
boolean	supportsPlannerLevel(PlannerLevel plannerLevel)

Methods inherited from class cascading.operation.expression.ExpressionOperation

equals, evaluate, hashCode, prepare

Methods inherited from class cascading.operation.BaseOperation

cleanup, getFieldDeclaration, getNumArgs, getTrace, isSafe, printOperationInternal, toString, toStringInternal

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface cascading.operation.Operation

cleanup, getFieldDeclaration, getNumArgs, isSafe, prepare

Constructor Detail

AssertExpression

@ConstructorProperties(value={"expression","parameterType"})
public AssertExpression(String expression,
                                                   Class parameterType)

Constructor ExpressionFilter creates a new ExpressionFilter instance.

Parameters:

expression - of type String

parameterType - of type Class

AssertExpression

@ConstructorProperties(value={"fieldDeclaration","expression","parameterNames","parameterTypes"})
public AssertExpression(Fields fieldDeclaration,
                                                   String expression,
                                                   String[] parameterNames,
                                                   Class[] parameterTypes)

Constructor AssertExpression creates a new AssertExpression instance.

Parameters:

fieldDeclaration - of type Fields

expression - of type String

parameterNames - of type String[]

parameterTypes - of type Class[]

Method Detail

supportsPlannerLevel

public boolean supportsPlannerLevel(PlannerLevel plannerLevel)

Specified by:

supportsPlannerLevel in interface PlannedOperation<ExpressionOperation.Context>

doAssert

public void doAssert(FlowProcess flowProcess,
                     ValueAssertionCall<ExpressionOperation.Context> assertionCall)

Description copied from interface: ValueAssertion

Method doAssert performs the assertion.

Specified by:

doAssert in interface ValueAssertion<ExpressionOperation.Context>

Parameters:

flowProcess - of type FlowProcess

assertionCall - of type ValueAssertionCall

See Also:

ValueAssertion.doAssert(cascading.flow.FlowProcess,cascading.operation.ValueAssertionCall)