Package net.sf.saxon.s9api.streams

Class Step<T extends XdmItem>

  • Type Parameters:
    T - the type of XdmItem that is returned by the step. (Note that we don't parameterize Steps by the type of input item).
    All Implemented Interfaces:
    java.util.function.Function<XdmItem,​java.util.stream.Stream<? extends T>>
    public abstract class Step<T extends XdmItem>
extends java.lang.Object
implements java.util.function.Function<XdmItem,​java.util.stream.Stream<? extends T>>
    A Step is a function that can be applied to an item to return a stream of items.
    See Also:
    Steps

    • Constructor Summary

      Constructors 
      Constructor Description
      Step()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Step<T> at​(long index)
      Obtain a step that selects the Nth item in the results of this step
      Step<T> cat​(Step<T> other)
      Obtain a Step that concatenates the results of this Step with the result of another Step applied to the same input item.
      Step<T> first()
      Obtain a step that selects the first item in the results of this step
      Step<T> last()
      Obtain a step that selects the last item in the results of this step
      <U extends XdmItem>
      Step<U>      		 then​(Step<U> next)
      Obtain a step that combines the results of this step with the results of another step
      Step<T> where​(java.util.function.Predicate<? super T> predicate)
      Obtain a Step that filters the results of this Step using a supplied predicate.

      • Methods inherited from class java.lang.Object

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

      • Methods inherited from interface java.util.function.Function

        andThen, apply, compose

    • Constructor Detail

      • Step

        public Step()

    • Method Detail

      • where

        public Step<T> where​(java.util.function.Predicate<? super T> predicate)
        Obtain a Step that filters the results of this Step using a supplied predicate.

        For example, CHILD.where(isText()) returns a Step whose effect is to select the text node children of a supplied element or document node.

        Parameters:
        predicate - the predicate which will be applied to the results of this step
        Returns:
        a new Step (that is, a function from one Stream of items to another) that filters the results of this step by selecting only the items that satisfy the predicate.

      • cat

        public Step<T> cat​(Step<T> other)
        Obtain a Step that concatenates the results of this Step with the result of another Step applied to the same input item.

        For example, attribute().cat(child()) returns a step whose effect is to select the attributes of a supplied element followed by its children.

        Parameters:
        other - the step whose results will be concatenated with the results of this step
        Returns:
        a new Step (that is, a function from one Stream of items to another) that concatenates the results of applying this step to the input item, followed by the results of applying the other step to the input item.

      • first

        public Step<T> first()
        Obtain a step that selects the first item in the results of this step
        Returns:
        a new Step (that is, a function from one Stream of items to another) that filters the results of this step by selecting only the first item.

      • last

        public Step<T> last()
        Obtain a step that selects the last item in the results of this step
        Returns:
        a new Step (that is, a function from one Stream of items to another) that filters the results of this step by selecting only the last item.

      • at

        public Step<T> at​(long index)
        Obtain a step that selects the Nth item in the results of this step
        Parameters:
        index - the zero-based index of the item to be selected
        Returns:
        a new Step (that is, a function from one Stream of items to another) that filters the results of this step by selecting only the items that satisfy the predicate.

      • then

        public <U extends XdmItem> Step<U> then​(Step<U> next)
        Obtain a step that combines the results of this step with the results of another step
        Parameters:
        next - the step which will be applied to the results of this step
        Returns:
        a new Step (that is, a function from one Stream of items to another) that performs this step and the next step in turn. The result is equivalent to the Java {code flatMap()} function or the XPath {code !} operator: there is no sorting of nodes into document order, and no elimination of duplicates.