enumj

Class AbstractPipeProcessor<T,R>

java.lang.Object

enumj.AbstractPipeProcessor<T,R>

Type Parameters:

T - Type of element being processed.

R - Type of processed result.

Direct Known Subclasses:

AbstractPipeMultiProcessor, FilterPipeProcessor, LimitPipeProcessor, MapPipeProcessor, SkipPipeProcessor, SkipWhilePipeProcessor, WhilePipeProcessor, ZipPipeProcessor

abstract class AbstractPipeProcessor<T,R>
extends Object

Pipe processor that receives an element, processes it and returns an output.

See Also:

PipeEnumerator, AbstractPipeMultiProcessor

Field Summary

Fields

Modifier and Type	Field and Description
boolean	hasNextNeedsValue Represents whether the processor needs an input value to participate to the outcome of PipeEnumerator.hasNext().
boolean	nextOnSameSourceOnNoValue Represents whether the pipeline should proceed to the next element of the same source when hasOutputValue() returns false.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractPipeProcessor(boolean nextOnSameSourceOnNoValue, boolean hasNextNeedsValue) Constructs a new instance of AbstractPipeProcessor.

Method Summary

Modifier and Type	Method and Description
protected abstract void	clearOutputValue() Clears the processed result after being returned by AbstractPipeProcessor.retrieveOutputValue().
boolean	enqueueFilter(Predicate<R> predicate) Returns true and aggregates the given predicate to the end of existing predicates, otherwise it returns false.
<U> boolean	enqueueMap(Function<R,U> mapper) Returns true and aggregates the given mapper to the end of existing mappers, otherwise it returns false.
AbstractPipeProcessor<? extends R,?>	getNext() Returns the value of AbstractPipeProcessor.next.
R	getOutputValue() Gets the processed result produced by AbstractPipeProcessor.processInputValue(T) and clears the internal storage of it.
PipeSource	getSource() Gets the value of AbstractPipeProcessor.source.
abstract boolean	hasOutputValue() Gets whether processing was successful and the processor has a value to yield.
abstract boolean	isInactive() Gets whether the processor does not process any more and the pipeline up to it should be discarded.
abstract void	processInputValue(T value) Processes an input value in order to return a result, if any.
boolean	pushFrontFilter(Predicate<R> predicate) Returns true and aggregates the given predicate to the top of the existing predicates, otherwise it returns false.
<U> boolean	pushFrontMap(Function<R,U> mapper) Returns true and aggregates the given mapper to the top of the existing mappers, otherwise it returns false.
protected abstract R	retrieveOutputValue() Retrieves the processed result produced by AbstractPipeProcessor.processInputValue(Object).
void	setNext(AbstractPipeProcessor<? extends R,?> next) Sets the value of AbstractPipeProcessor.next.
void	setSource(PipeSource reference) Sets the value of AbstractPipeProcessor.source.

Methods inherited from class java.lang.Object

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

Field Detail

nextOnSameSourceOnNoValue

public final boolean nextOnSameSourceOnNoValue

Represents whether the pipeline should proceed to the next element of the same source when hasOutputValue() returns false.

See Also:

hasOutputValue(), hasNextNeedsValue

hasNextNeedsValue

public final boolean hasNextNeedsValue

Represents whether the processor needs an input value to participate to the outcome of PipeEnumerator.hasNext().

See Also:

AbstractEnumerator.hasNext(), nextOnSameSourceOnNoValue

Constructor Detail

AbstractPipeProcessor

protected AbstractPipeProcessor(boolean nextOnSameSourceOnNoValue,
                                boolean hasNextNeedsValue)

Constructs a new instance of AbstractPipeProcessor.

Parameters:

nextOnSameSourceOnNoValue - value for nextOnSameSourceOnNoValue.

hasNextNeedsValue - value for hasNextNeedsValue.

Method Detail

getNext

public AbstractPipeProcessor<? extends R,?> getNext()

Returns the value of AbstractPipeProcessor.next.

Returns:

Value of next.

See Also:

setNext(enumj.AbstractPipeProcessor)

setNext

public void setNext(AbstractPipeProcessor<? extends R,?> next)

Sets the value of AbstractPipeProcessor.next.

Once next is set to a non-null value, it may not change.

Parameters:

next - Value for next.

Throws:

UnsupportedOperationException - next is being set twice.

See Also:

getNext()

getSource

public PipeSource getSource()

Gets the value of AbstractPipeProcessor.source.

Returns:

Value of source.

See Also:

setSource(enumj.PipeSource)

setSource

public void setSource(PipeSource reference)

Sets the value of AbstractPipeProcessor.source.

Once source is set to a non-null value, it may not change.

Parameters:

reference - Value for source.

See Also:

getSource()

pushFrontMap

public <U> boolean pushFrontMap(Function<R,U> mapper)

Returns true and aggregates the given mapper to the top of the existing mappers, otherwise it returns false.

This method returns false by default. The only AbstractPipeProcessor capable of mapping aggregation is MapPipeProcessor.

Type Parameters:

U - type of mapped enumerated elements.

Parameters:

mapper - mapping Function.

Returns:

true on successful aggregation of mappers, false otherwise.

enqueueMap

public <U> boolean enqueueMap(Function<R,U> mapper)

Returns true and aggregates the given mapper to the end of existing mappers, otherwise it returns false.

This method returns false by default. The only AbstractPipeProcessor capable of mapping aggregation is MapPipeProcessor.

Type Parameters:

U - type of mapped enumerated elements.

Parameters:

mapper - mapping Function.

Returns:

true on successful aggregation of mappers, false otherwise.

pushFrontFilter

public boolean pushFrontFilter(Predicate<R> predicate)

Returns true and aggregates the given predicate to the top of the existing predicates, otherwise it returns false.

This method returns false by default. The only AbstractPipeProcessor capable of predicate aggregation is FilterPipeProcessor.

Parameters:

predicate - filtering Predicate.

Returns:

true on successful aggregation of predicates, false otherwise.

enqueueFilter

public boolean enqueueFilter(Predicate<R> predicate)

Returns true and aggregates the given predicate to the end of existing predicates, otherwise it returns false.

This method returns false by default. The only AbstractPipeProcessor capable of mapping aggregation is FilterPipeProcessor.

Parameters:

predicate - filtering Predicate.

Returns:

true on successful aggregation of predicates, false otherwise.

processInputValue

public abstract void processInputValue(T value)

Processes an input value in order to return a result, if any.

The result of processing must be stored internally.

Parameters:

value - Value to process.

See Also:

hasOutputValue(), getOutputValue()

hasOutputValue

public abstract boolean hasOutputValue()

Gets whether processing was successful and the processor has a value to yield.

If hasOutputValue() returns false than no internal storage of input or output may take place.

Returns:

true if there is an output value to yield, false otherwise.

See Also:

processInputValue(java.lang.Object), getOutputValue()

getOutputValue

public final R getOutputValue()

Gets the processed result produced by AbstractPipeProcessor.processInputValue(T) and clears the internal storage of it.

Returns:

Processed result.

See Also:

processInputValue(Object), hasOutputValue(), retrieveOutputValue(), clearOutputValue()

retrieveOutputValue

protected abstract R retrieveOutputValue()

Retrieves the processed result produced by AbstractPipeProcessor.processInputValue(Object).

Returns:

Processed result.

See Also:

getOutputValue(), clearOutputValue()

clearOutputValue

protected abstract void clearOutputValue()

Clears the processed result after being returned by AbstractPipeProcessor.retrieveOutputValue().

See Also:

getOutputValue(), retrieveOutputValue()

isInactive

public abstract boolean isInactive()

Gets whether the processor does not process any more and the pipeline up to it should be discarded.

isInactive() returning true is equivalent to the situation when no matter with what value processInputValue(Object) will be called, hasOutputValue() will always return false.

Most processors have this function return false with the exception of while and limit compositions. These will turn completely inactive once a certain condition is met.

Returns:

true if processing must stop, false otherwise.