Class Stream

java.lang.Object
org.apache.el.stream.Stream
public class Stream extends Object
A stream of elements supporting sequential operations such as filter, map, reduce, and various terminal operations.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Stream(Iterator<Object> iterator)
    Constructs a new Stream from the given iterator.

  • Method Summary

    Modifier and Type
    Method
    Description
    Optional
    allMatch(LambdaExpression le)
    Checks if all elements in the stream match the given predicate.
    Optional
    anyMatch(LambdaExpression le)
    Checks if any element in the stream matches the given predicate.
    Optional
    average()
    Calculates the average of all numeric elements in the stream.
    Long
    count()
    Counts the number of elements in the stream.
    Stream
    distinct()
    Returns a stream consisting of the distinct elements of this stream.
    Stream
    filter(LambdaExpression le)
    Returns a stream consisting of the elements that match the given predicate.
    Optional
    findFirst()
    Returns an Optional describing the first element of this stream, or an empty Optional if the stream is empty.
    Stream
    flatMap(LambdaExpression le)
    Returns a stream consisting of the results of replacing each element of this stream with the contents of a stream produced by applying the provided function to each element.
    Object
    forEach(LambdaExpression le)
    Performs an action for each element of this stream.
    Iterator<?>
    iterator()
    Returns the underlying iterator for this stream.
    Stream
    limit(Number count)
    Returns a stream consisting of the first count elements of this stream.
    Stream
    map(LambdaExpression le)
    Returns a stream consisting of the results of applying the given function to the elements of this stream.
    Optional
    max()
    Returns the maximum element of this stream according to natural order.
    Optional
    max(LambdaExpression le)
    Returns the maximum element of this stream according to the provided comparator.
    Optional
    min()
    Returns the minimum element of this stream according to natural order.
    Optional
    min(LambdaExpression le)
    Returns the minimum element of this stream according to the provided comparator.
    Optional
    noneMatch(LambdaExpression le)
    Checks if no elements of this stream match the given predicate.
    Stream
    peek(LambdaExpression le)
    Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed.
    Optional
    reduce(LambdaExpression le)
    Performs a reduction on the elements of this stream, using the provided accumulator function.
    Object
    reduce(Object seed, LambdaExpression le)
    Performs a reduction on the elements of this stream, using the provided initial value and accumulator function.
    Stream
    sorted()
    Returns a stream consisting of the elements of this stream, sorted according to natural order.
    Stream
    sorted(LambdaExpression le)
    Returns a stream consisting of the elements of this stream, sorted according to the order induced by the provided comparator.
    Stream
    substream(Number start)
    Returns a stream consisting of the elements of this stream from the specified start position to the end.
    Stream
    substream(Number start, Number end)
    Returns a stream consisting of the elements of this stream from the specified start position up to, but not including, the specified end position.
    Number
    sum()
    Returns the sum of all numeric elements in the stream.
    Object[]
    toArray()
    Returns an array containing all the elements of this stream.
    List<Object>
    toList()
    Returns a list containing all the elements of this stream.

    Methods inherited from class Object

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

  • Constructor Details

    • Stream

      public Stream(Iterator<Object> iterator)
      Constructs a new Stream from the given iterator.
      Parameters:
      iterator - the iterator providing the stream elements

  • Method Details

    • filter

      public Stream filter(LambdaExpression le)
      Returns a stream consisting of the elements that match the given predicate.
      Parameters:
      le - the predicate to apply to each element
      Returns:
      the new filtered stream

    • map

      public Stream map(LambdaExpression le)
      Returns a stream consisting of the results of applying the given function to the elements of this stream.
      Parameters:
      le - the function to apply to each element
      Returns:
      the new mapped stream

    • flatMap

      public Stream flatMap(LambdaExpression le)
      Returns a stream consisting of the results of replacing each element of this stream with the contents of a stream produced by applying the provided function to each element.
      Parameters:
      le - the function to apply to each element which produces a new stream
      Returns:
      the new flattened stream

    • distinct

      public Stream distinct()
      Returns a stream consisting of the distinct elements of this stream.
      Returns:
      the new stream with distinct elements

    • sorted

      public Stream sorted()
      Returns a stream consisting of the elements of this stream, sorted according to natural order.
      Returns:
      the new sorted stream

    • sorted

      public Stream sorted(LambdaExpression le)
      Returns a stream consisting of the elements of this stream, sorted according to the order induced by the provided comparator.
      Parameters:
      le - the comparator to determine sort order
      Returns:
      the new sorted stream

    • forEach

      public Object forEach(LambdaExpression le)
      Performs an action for each element of this stream.
      Parameters:
      le - the action to perform for each element
      Returns:
      null

    • peek

      public Stream peek(LambdaExpression le)
      Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed.
      Parameters:
      le - the action to perform on each element
      Returns:
      the new stream

    • iterator

      public Iterator<?> iterator()
      Returns the underlying iterator for this stream.
      Returns:
      the underlying iterator

    • limit

      public Stream limit(Number count)
      Returns a stream consisting of the first count elements of this stream.
      Parameters:
      count - the number of elements to limit to
      Returns:
      the new limited stream

    • substream

      public Stream substream(Number start)
      Returns a stream consisting of the elements of this stream from the specified start position to the end.
      Parameters:
      start - the start position (inclusive)
      Returns:
      the new substream

    • substream

      public Stream substream(Number start, Number end)
      Returns a stream consisting of the elements of this stream from the specified start position up to, but not including, the specified end position.
      Parameters:
      start - the start position (inclusive)
      end - the end position (exclusive)
      Returns:
      the new substream

    • toList

      public List<Object> toList()
      Returns a list containing all the elements of this stream.
      Returns:
      the list of elements

    • toArray

      public Object[] toArray()
      Returns an array containing all the elements of this stream.
      Returns:
      the array of elements

    • reduce

      public Optional reduce(LambdaExpression le)
      Performs a reduction on the elements of this stream, using the provided accumulator function. The first element is used as the initial value.
      Parameters:
      le - the accumulator function
      Returns:
      an Optional describing the reduced value, or empty if this stream is empty

    • reduce

      public Object reduce(Object seed, LambdaExpression le)
      Performs a reduction on the elements of this stream, using the provided initial value and accumulator function.
      Parameters:
      seed - the initial value for the reduction
      le - the accumulator function
      Returns:
      the result of the reduction

    • max

      public Optional max()
      Returns the maximum element of this stream according to natural order.
      Returns:
      an Optional describing the maximum element, or empty if this stream is empty

    • max

      public Optional max(LambdaExpression le)
      Returns the maximum element of this stream according to the provided comparator.
      Parameters:
      le - the comparator to determine the maximum
      Returns:
      an Optional describing the maximum element, or empty if this stream is empty

    • min

      public Optional min()
      Returns the minimum element of this stream according to natural order.
      Returns:
      an Optional describing the minimum element, or empty if this stream is empty

    • min

      public Optional min(LambdaExpression le)
      Returns the minimum element of this stream according to the provided comparator.
      Parameters:
      le - the comparator to determine the minimum
      Returns:
      an Optional describing the minimum element, or empty if this stream is empty

    • average

      public Optional average()
      Calculates the average of all numeric elements in the stream.
      Returns:
      an Optional containing the average, or empty if the stream is empty

    • sum

      public Number sum()
      Returns the sum of all numeric elements in the stream.
      Returns:
      the sum of all elements

    • count

      public Long count()
      Counts the number of elements in the stream.
      Returns:
      the number of elements

    • anyMatch

      public Optional anyMatch(LambdaExpression le)
      Checks if any element in the stream matches the given predicate.
      Parameters:
      le - the predicate lambda expression
      Returns:
      an Optional containing true if any element matches, or empty if the stream is empty

    • allMatch

      public Optional allMatch(LambdaExpression le)
      Checks if all elements in the stream match the given predicate.
      Parameters:
      le - the predicate lambda expression
      Returns:
      an Optional containing true if all elements match, or empty if the stream is empty

    • noneMatch

      public Optional noneMatch(LambdaExpression le)
      Checks if no elements of this stream match the given predicate.
      Parameters:
      le - the predicate lambda expression
      Returns:
      an Optional containing true if no elements match, or empty if the stream is empty

    • findFirst

      public Optional findFirst()
      Returns an Optional describing the first element of this stream, or an empty Optional if the stream is empty.
      Returns:
      an Optional describing the first element of this stream