Package com.tangosol.util.stream

Interface RemoteDoubleStream

All Superinterfaces:
AutoCloseable, BaseRemoteStream<Double,DoubleStream>, BaseStream<Double,DoubleStream>, DoubleStream
public interface RemoteDoubleStream extends DoubleStream, BaseRemoteStream<Double,DoubleStream>
A sequence of primitive double-valued elements supporting sequential and parallel aggregate operations. This is the double primitive specialization of RemoteStream.

The following example illustrates an aggregate operation using RemoteStream and RemoteDoubleStream, computing the sum of the weights of the red widgets: 


     double sum = widgets.stream()
                         .filter(w -> w.getColor() == RED)
                         .mapToDouble(w -> w.getWeight())
                         .sum();

This interface is an extension of java.util.stream.DoubleStream that captures lambdas used as method arguments as serializable lambdas.

Since:
12.2.1
Author:
as 2014.09.11
See Also:

  • Method Details

    • filter

      RemoteDoubleStream filter(DoublePredicate predicate)
      Returns a stream consisting of the elements of this stream that match the given predicate.

      This is an intermediate operation.

      Specified by:
      filter in interface DoubleStream
      Parameters:
      predicate - a non-interfering, stateless predicate to apply to each element to determine if it should be included
      Returns:
      the new stream

    • filter

      default RemoteDoubleStream filter(Remote.DoublePredicate predicate)
      Returns a stream consisting of the elements of this stream that match the given predicate.

      This is an intermediate operation.

      Parameters:
      predicate - a non-interfering, stateless predicate to apply to each element to determine if it should be included
      Returns:
      the new stream

    • map

      RemoteDoubleStream map(DoubleUnaryOperator mapper)
      Returns a stream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Specified by:
      map in interface DoubleStream
      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • map

      default RemoteDoubleStream map(Remote.DoubleUnaryOperator mapper)
      Returns a stream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • mapToObj

      <U> RemoteStream<U> mapToObj(DoubleFunction<? extends U> mapper)
      Returns an object-valued Stream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Specified by:
      mapToObj in interface DoubleStream
      Type Parameters:
      U - the element type of the new stream
      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • mapToObj

      default <U> RemoteStream<U> mapToObj(Remote.DoubleFunction<? extends U> mapper)
      Returns an object-valued Stream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Type Parameters:
      U - the element type of the new stream
      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • mapToInt

      RemoteIntStream mapToInt(DoubleToIntFunction mapper)
      Returns an IntStream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Specified by:
      mapToInt in interface DoubleStream
      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • mapToInt

      default RemoteIntStream mapToInt(Remote.DoubleToIntFunction mapper)
      Returns an IntStream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • mapToLong

      RemoteLongStream mapToLong(DoubleToLongFunction mapper)
      Returns a LongStream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Specified by:
      mapToLong in interface DoubleStream
      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • mapToLong

      default RemoteLongStream mapToLong(Remote.DoubleToLongFunction mapper)
      Returns a LongStream consisting of the results of applying the given function to the elements of this stream.

      This is an intermediate operation.

      Parameters:
      mapper - a non-interfering, stateless function to apply to each element
      Returns:
      the new stream

    • flatMap

      RemoteDoubleStream flatMap(DoubleFunction<? extends DoubleStream> mapper)
      Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element. Each mapped stream is closed after its contents have been placed into this stream. (If a mapped stream is null an empty stream is used, instead.)

      This is an intermediate operation.

      Specified by:
      flatMap in interface DoubleStream
      Parameters:
      mapper - a non-interfering, stateless function to apply to each element which produces a DoubleStream of new values
      Returns:
      the new stream
      See Also:

    • flatMap

      default RemoteDoubleStream flatMap(Remote.DoubleFunction<? extends DoubleStream> mapper)
      Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element. Each mapped stream is closed after its contents have been placed into this stream. (If a mapped stream is null an empty stream is used, instead.)

      This is an intermediate operation.

      Parameters:
      mapper - a non-interfering, stateless function to apply to each element which produces a DoubleStream of new values
      Returns:
      the new stream
      See Also:

    • peek

      RemoteDoubleStream peek(DoubleConsumer action)
      Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.

      This is an intermediate operation.

      For parallel stream pipelines, the action may be called at whatever time and in whatever thread the element is made available by the upstream operation. If the action modifies shared state, it is responsible for providing the required synchronization.

      Specified by:
      peek in interface DoubleStream
      Parameters:
      action - a non-interfering action to perform on the elements as they are consumed from the stream
      Returns:
      the new stream

    • peek

      default RemoteDoubleStream peek(Remote.DoubleConsumer action)
      Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.

      This is an intermediate operation.

      For parallel stream pipelines, the action may be called at whatever time and in whatever thread the element is made available by the upstream operation. If the action modifies shared state, it is responsible for providing the required synchronization.

      Parameters:
      action - a non-interfering action to perform on the elements as they are consumed from the stream
      Returns:
      the new stream

    • distinct

      DoubleStream distinct()
      Returns a stream consisting of the distinct elements of this stream. The elements are compared for equality according to Double.compare(double, double).

      This is a stateful intermediate operation.

      Specified by:
      distinct in interface DoubleStream
      Returns:
      the result stream

    • sorted

      DoubleStream sorted()
      Returns a stream consisting of the elements of this stream in sorted order. The elements are compared for equality according to Double.compare(double, double).

      This is a stateful intermediate operation.

      Specified by:
      sorted in interface DoubleStream
      Returns:
      the result stream

    • limit

      DoubleStream limit(long maxSize)
      Returns a stream consisting of the elements of this stream, truncated to be no longer than maxSize in length.

      This is a short-circuiting stateful intermediate operation.

      Specified by:
      limit in interface DoubleStream
      Parameters:
      maxSize - the number of elements the stream should be limited to
      Returns:
      the new stream
      Throws:
      IllegalArgumentException - if maxSize is negative

    • skip

      DoubleStream skip(long n)
      Returns a stream consisting of the remaining elements of this stream after discarding the first n elements of the stream. If this stream contains fewer than n elements then an empty stream will be returned.

      This is a stateful intermediate operation.

      Specified by:
      skip in interface DoubleStream
      Parameters:
      n - the number of leading elements to skip
      Returns:
      the new stream
      Throws:
      IllegalArgumentException - if n is negative

    • forEach

      void forEach(DoubleConsumer action)
      Performs an action for each element of this stream.

      This is a terminal operation.

      For parallel stream pipelines, this operation does not guarantee to respect the encounter order of the stream, as doing so would sacrifice the benefit of parallelism. For any given element, the action may be performed at whatever time and in whatever thread the library chooses. If the action accesses shared state, it is responsible for providing the required synchronization.

      Specified by:
      forEach in interface DoubleStream
      Parameters:
      action - a non-interfering action to perform on the elements

    • forEachOrdered

      void forEachOrdered(DoubleConsumer action)
      Performs an action for each element of this stream, guaranteeing that each element is processed in encounter order for streams that have a defined encounter order.

      This is a terminal operation.

      Specified by:
      forEachOrdered in interface DoubleStream
      Parameters:
      action - a non-interfering action to perform on the elements
      See Also:

    • toArray

      double[] toArray()
      Returns an array containing the elements of this stream.

      This is a terminal operation.

      Specified by:
      toArray in interface DoubleStream
      Returns:
      an array containing the elements of this stream

    • reduce

      double reduce(double identity, DoubleBinaryOperator op)
      Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value. This is equivalent to: 
      
     double result = identity;
     for (double element : this stream)
         result = accumulator.applyAsDouble(result, element)
     return result;
      but is not constrained to execute sequentially.

      The identity value must be an identity for the accumulator function. This means that for all x, accumulator.apply(identity, x) is equal to x. The accumulator function must be an associative function.

      This is a terminal operation.

      Specified by:
      reduce in interface DoubleStream
      Parameters:
      identity - the identity value for the accumulating function
      op - an associative, non-interfering, stateless function for combining two values
      Returns:
      the result of the reduction
      See Also:

    • reduce

      default double reduce(double identity, Remote.DoubleBinaryOperator op)
      Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value. This is equivalent to: 
      
     double result = identity;
     for (double element : this stream)
         result = accumulator.applyAsDouble(result, element)
     return result;
      but is not constrained to execute sequentially.

      The identity value must be an identity for the accumulator function. This means that for all x, accumulator.apply(identity, x) is equal to x. The accumulator function must be an associative function.

      This is a terminal operation.

      Parameters:
      identity - the identity value for the accumulating function
      op - an associative, non-interfering, stateless function for combining two values
      Returns:
      the result of the reduction
      See Also:

    • reduce

      OptionalDouble reduce(DoubleBinaryOperator op)
      Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an OptionalDouble describing the reduced value, if any. This is equivalent to: 
      
     boolean foundAny = false;
     double result = null;
     for (double element : this stream) {
         if (!foundAny) {
             foundAny = true;
             result = element;
         }
         else
             result = accumulator.applyAsDouble(result, element);
     }
     return foundAny ? OptionalDouble.of(result) : OptionalDouble.empty();
      but is not constrained to execute sequentially.

      The accumulator function must be an associative function.

      This is a terminal operation.

      Specified by:
      reduce in interface DoubleStream
      Parameters:
      op - an associative, non-interfering, stateless function for combining two values
      Returns:
      the result of the reduction
      See Also:

    • reduce

      default OptionalDouble reduce(Remote.DoubleBinaryOperator op)
      Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an OptionalDouble describing the reduced value, if any. This is equivalent to: 
      
     boolean foundAny = false;
     double result = null;
     for (double element : this stream) {
         if (!foundAny) {
             foundAny = true;
             result = element;
         }
         else
             result = accumulator.applyAsDouble(result, element);
     }
     return foundAny ? OptionalDouble.of(result) : OptionalDouble.empty();
      but is not constrained to execute sequentially.

      The accumulator function must be an associative function.

      This is a terminal operation.

      Parameters:
      op - an associative, non-interfering, stateless function for combining two values
      Returns:
      the result of the reduction
      See Also:

    • collect

      <R> R collect(Supplier<R> supplier, ObjDoubleConsumer<R> accumulator, BiConsumer<R,R> combiner)
      Performs a mutable reduction operation on the elements of this stream. A mutable reduction is one in which the reduced value is a mutable result container, such as an ArrayList, and elements are incorporated by updating the state of the result rather than by replacing the result.

      This produces a result equivalent to: 

      
     R result = supplier.get();
     for (double element : this stream)
         accumulator.accept(result, element);
     return result;

      Like reduce(double, DoubleBinaryOperator), collect operations can be parallelized without requiring additional synchronization.

      This is a terminal operation.

      Specified by:
      collect in interface DoubleStream
      Type Parameters:
      R - type of the result
      Parameters:
      supplier - a function that creates a new result container. For a parallel execution, this function may be called multiple times and must return a fresh value each time.
      accumulator - an associative, non-interfering, stateless function for incorporating an additional element into a result
      combiner - an associative, non-interfering, stateless function for combining two values, which must be compatible with the accumulator function
      Returns:
      the result of the reduction
      See Also:

    • collect

      default <R> R collect(Remote.Supplier<R> supplier, Remote.ObjDoubleConsumer<R> accumulator, Remote.BiConsumer<R,R> combiner)
      Performs a mutable reduction operation on the elements of this stream. A mutable reduction is one in which the reduced value is a mutable result container, such as an ArrayList, and elements are incorporated by updating the state of the result rather than by replacing the result.

      This produces a result equivalent to: 

      
     R result = supplier.get();
     for (double element : this stream)
         accumulator.accept(result, element);
     return result;

      Like reduce(double, DoubleBinaryOperator), collect operations can be parallelized without requiring additional synchronization.

      This is a terminal operation.

      Type Parameters:
      R - type of the result
      Parameters:
      supplier - a function that creates a new result container. For a parallel execution, this function may be called multiple times and must return a fresh value each time.
      accumulator - an associative, non-interfering, stateless function for incorporating an additional element into a result
      combiner - an associative, non-interfering, stateless function for combining two values, which must be compatible with the accumulator function
      Returns:
      the result of the reduction
      See Also:

    • sum

      double sum()
      Returns the sum of elements in this stream.

      Summation is a special case of a reduction. If floating-point summation were exact, this method would be equivalent to: 

      
     return reduce(0, Double::sum);
      However, since floating-point summation is not exact, the above code is not necessarily equivalent to the summation computation done by this method.

      If any stream element is a NaN or the sum is at any point a NaN then the sum will be NaN.

      The value of a floating-point sum is a function both of the input values as well as the order of addition operations. The order of addition operations of this method is intentionally not defined to allow for implementation flexibility to improve the speed and accuracy of the computed result.

      In particular, this method may be implemented using compensated summation or other technique to reduce the error bound in the numerical sum compared to a simple summation of double values.

      This is a terminal operation.

      Specified by:
      sum in interface DoubleStream
      Returns:
      the sum of elements in this stream

    • min

      OptionalDouble min()
      Returns an OptionalDouble describing the minimum element of this stream, or an empty OptionalDouble if this stream is empty. The minimum element will be Double.NaN if any stream element was NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. This is a special case of a reduction and is equivalent to: 
      
     return reduce(Double::min);

      This is a terminal operation.

      Specified by:
      min in interface DoubleStream
      Returns:
      an OptionalDouble containing the minimum element of this stream, or an empty optional if the stream is empty

    • max

      OptionalDouble max()
      Returns an OptionalDouble describing the maximum element of this stream, or an empty OptionalDouble if this stream is empty. The maximum element will be Double.NaN if any stream element was NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. This is a special case of a reduction and is equivalent to: 
      
     return reduce(Double::max);

      This is a terminal operation.

      Specified by:
      max in interface DoubleStream
      Returns:
      an OptionalDouble containing the maximum element of this stream, or an empty optional if the stream is empty

    • count

      long count()
      Returns the count of elements in this stream. This is a special case of a reduction and is equivalent to: 
      
     return mapToLong(e -> 1L).sum();

      This is a terminal operation.

      Specified by:
      count in interface DoubleStream
      Returns:
      the count of elements in this stream

    • average

      OptionalDouble average()
      Returns an OptionalDouble describing the arithmetic mean of elements of this stream, or an empty optional if this stream is empty.

      If any recorded value is a NaN or the sum is at any point a NaN then the average will be NaN.

      The average returned can vary depending upon the order in which values are recorded.

      This method may be implemented using compensated summation or other technique to reduce the error bound in the numerical sum used to compute the average.

      This is a terminal operation.

      Specified by:
      average in interface DoubleStream
      Returns:
      an OptionalDouble containing the average element of this stream, or an empty optional if the stream is empty

    • summaryStatistics

      DoubleSummaryStatistics summaryStatistics()
      Returns a DoubleSummaryStatistics describing various summary data about the elements of this stream. This is a special case of a reduction.

      This is a terminal operation.

      Specified by:
      summaryStatistics in interface DoubleStream
      Returns:
      a DoubleSummaryStatistics describing various summary data about the elements of this stream

    • anyMatch

      boolean anyMatch(DoublePredicate predicate)
      Returns whether any elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then false is returned and the predicate is not evaluated.

      This is a short-circuiting terminal operation.

      Specified by:
      anyMatch in interface DoubleStream
      Parameters:
      predicate - a non-interfering, stateless predicate to apply to elements of this stream
      Returns:
      true if any elements of the stream match the provided predicate, otherwise false

    • anyMatch

      default boolean anyMatch(Remote.DoublePredicate predicate)
      Returns whether any elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then false is returned and the predicate is not evaluated.

      This is a short-circuiting terminal operation.

      Parameters:
      predicate - a non-interfering, stateless predicate to apply to elements of this stream
      Returns:
      true if any elements of the stream match the provided predicate, otherwise false

    • allMatch

      boolean allMatch(DoublePredicate predicate)
      Returns whether all elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

      This is a short-circuiting terminal operation.

      Specified by:
      allMatch in interface DoubleStream
      Parameters:
      predicate - a non-interfering, stateless predicate to apply to elements of this stream
      Returns:
      true if either all elements of the stream match the provided predicate or the stream is empty, otherwise false

    • allMatch

      default boolean allMatch(Remote.DoublePredicate predicate)
      Returns whether all elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

      This is a short-circuiting terminal operation.

      Parameters:
      predicate - a non-interfering, stateless predicate to apply to elements of this stream
      Returns:
      true if either all elements of the stream match the provided predicate or the stream is empty, otherwise false

    • noneMatch

      boolean noneMatch(DoublePredicate predicate)
      Returns whether no elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

      This is a short-circuiting terminal operation.

      Specified by:
      noneMatch in interface DoubleStream
      Parameters:
      predicate - a non-interfering, stateless predicate to apply to elements of this stream
      Returns:
      true if either no elements of the stream match the provided predicate or the stream is empty, otherwise false

    • noneMatch

      default boolean noneMatch(Remote.DoublePredicate predicate)
      Returns whether no elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

      This is a short-circuiting terminal operation.

      Parameters:
      predicate - a non-interfering, stateless predicate to apply to elements of this stream
      Returns:
      true if either no elements of the stream match the provided predicate or the stream is empty, otherwise false

    • findFirst

      OptionalDouble findFirst()
      Returns an OptionalDouble describing the first element of this stream, or an empty OptionalDouble if the stream is empty. If the stream has no encounter order, then any element may be returned.

      This is a short-circuiting terminal operation.

      Specified by:
      findFirst in interface DoubleStream
      Returns:
      an OptionalDouble describing the first element of this stream, or an empty OptionalDouble if the stream is empty

    • findAny

      OptionalDouble findAny()
      Returns an OptionalDouble describing some element of the stream, or an empty OptionalDouble if the stream is empty.

      This is a short-circuiting terminal operation.

      The behavior of this operation is explicitly nondeterministic; it is free to select any element in the stream. This is to allow for maximal performance in parallel operations; the cost is that multiple invocations on the same source may not return the same result. (If a stable result is desired, use findFirst() instead.)

      Specified by:
      findAny in interface DoubleStream
      Returns:
      an OptionalDouble describing some element of this stream, or an empty OptionalDouble if the stream is empty
      See Also:

    • boxed

      RemoteStream<Double> boxed()
      Returns a Stream consisting of the elements of this stream, boxed to Double.

      This is an intermediate operation.

      Specified by:
      boxed in interface DoubleStream
      Returns:
      a Stream consistent of the elements of this stream, each boxed to a Double

    • sequential

      RemoteDoubleStream sequential()
      Specified by:
      sequential in interface BaseStream<Double,DoubleStream>
      Specified by:
      sequential in interface DoubleStream

    • parallel

      RemoteDoubleStream parallel()
      Specified by:
      parallel in interface BaseStream<Double,DoubleStream>
      Specified by:
      parallel in interface DoubleStream

    • iterator

      PrimitiveIterator.OfDouble iterator()
      Specified by:
      iterator in interface BaseStream<Double,DoubleStream>
      Specified by:
      iterator in interface DoubleStream

    • spliterator

      Spliterator.OfDouble spliterator()
      Specified by:
      spliterator in interface BaseStream<Double,DoubleStream>
      Specified by:
      spliterator in interface DoubleStream