Package dev.aherscu.qa.testing.extra.supermachine

Class Scanner<T>

  • Type Parameters:
    T - the type of elements composing the data structure.
    Direct Known Subclasses:
    BeanScanner, StreamScanner
    public abstract class Scanner<T>
extends Object
    Abstraction wrapping a data structure that can be walked through to produce streams.

    • Constructor Detail

      • Scanner

        protected Scanner​(Stream<T> source)
        Constructs a scanner out of a source stream.
        Parameters:
        source - the wrapped stream, will contain only one element when it is a root.

    • Method Detail

      • extract

        public <X> Scanner<X> extract​(Function<T,​X> extractor)
        Apply a function to every items of this scanner and returns a scanner emitting the non-null results.
        Type Parameters:
        X - the returned type.
        Parameters:
        extractor - the function applied to each item, can return null.
        Returns:
        a scanner emitting non-null results of the function applied to items.

      • filter

        public Scanner<T> filter​(Predicate<T> predicate)
        Filters out items according to predicate.
        Parameters:
        predicate - the condition to emit the items.
        Returns:
        a scanner emitting the items matching the predicate.

      • find

        public <X> Scanner<X> find​(Class<X> clazz)
        Scans the elements of the source and returns a scanner emitting relevant items of the given type. This method can return fewer items according to subclass logic. Subclasses implement the actual scanning algorithm.
        Type Parameters:
        X - type of the selector and resulting items.
        Parameters:
        clazz - the type selector.
        Returns:
        a scanner emitting the selected items.

      • stream

        public Stream<T> stream()
        Extracts the items of this scanner as a stream.
        Returns:
        a stream of items.

      • then

        @SafeVarargs
public final <X> Scanner<X> then​(Function<Scanner<T>,​Scanner<X>>... fns)
        Transforms this scanner into one or more derived scanners and merges their emitted items.
        Type Parameters:
        X - the common type of items resulting of the scanners to merge.
        Parameters:
        fns - the functions that will be applied to this scanner and produce the scanners to merge.
        Returns:
        a scanner merging the result of the composed scanners.

      • walk

        public <X> Scanner<X> walk​(Class<X> clazz)
        Scans the elements of the source and returns a scanner emitting all resulting items of the given type. Subclasses implement the actual scanning algorithm.
        Type Parameters:
        X - type of the selector and resulting items.
        Parameters:
        clazz - the type selector.
        Returns:
        a scanner emitting the selected items.

      • create

        protected abstract <X> Scanner<X> create​(Stream<X> source)
        Constructs a scanner out of a source stream.
        Type Parameters:
        X - the type of elements in the source stream.
        Parameters:
        source - the wrapped stream, will contain only one element when it is a root.
        Returns:
        a scanner based on the given source.