Package com.singularsys.extensions.stream

Class StreamWhile

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.BinaryFunction

com.singularsys.extensions.stream.StreamWhile

All Implemented Interfaces:

JepComponent, PostfixMathCommandI, Serializable

public class StreamWhile
extends BinaryFunction
implements JepComponent

Filter a stream so only the elements from the start of the stream that match a criteria are returned. The first element which does not match the criteria and all subsequent elements are not included in the result stream. This allows potentially infinite streams to trimmed to a stream of finite length to be returned.

For example, if primes() returns an infinite stream of prime numbers, then

code primes() . while(p=> p<100)

will return a stream of all prime numbers less than 100.

The function uses the Java Stream method Stream.takeWhile(Predicate).

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.singularsys.jep.functions.BinaryFunction

BinaryFunction.BiFunctionWithException<T>

Field Summary

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, description, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
StreamWhile()

Method Summary

Modifier and Type	Method	Description
Object	eval(Object l, Object r)	Evaluate the function
JepComponent	getLightWeightInstance()	Gets a light-weight instance suitable for using in multiple threads.
void	init(Jep jep)	Initialize the component.

Methods inherited from class com.singularsys.jep.functions.BinaryFunction

instanceOf, instanceOf, instanceOf, instanceOf, run

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, asType, checkNumberOfParameters, getDescription, getDescription, getDescriptionWithType, getName, getNumberOfParameters, setCurNumberOfParameters, setDescription, setName, toString, toString

Methods inherited from class java.lang.Object

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

Constructor Details

StreamWhile

public StreamWhile()

Method Details

eval

public Object eval(Object l,
 Object r)
            throws EvaluationException

Description copied from class: BinaryFunction

Evaluate the function

Specified by:

eval in class BinaryFunction

Parameters:

l - lhs argument

r - rhs argument

Returns:

the results

Throws:

EvaluationException - if the function cannot be evaluated.

init

public void init(Jep jep)

Description copied from interface: JepComponent

Initialize the component. This method is called whenever a component is added to Jep. Hence, it allows components to keep track of the other components they may rely on.

Specified by:

init in interface JepComponent

Parameters:

jep - the current Jep instance

getLightWeightInstance

public JepComponent getLightWeightInstance()

Description copied from interface: JepComponent

Gets a light-weight instance suitable for using in multiple threads.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

either a new instance, null or 'this'.