org.apache.commons.collections4.functors

Class SwitchTransformer<I,O>

    • Constructor Detail

      • SwitchTransformer

        public SwitchTransformer(Predicate<? super I>[] predicates,
                         Transformer<? super I,? extends O>[] transformers,
                         Transformer<? super I,? extends O> defaultTransformer)
        Constructor that performs no validation. Use switchTransformer if you want that.
        Parameters:
        predicates - array of predicates, cloned, no nulls
        transformers - matching array of transformers, cloned, no nulls
        defaultTransformer - the transformer to use if no match, null means return null

    • Method Detail

      • switchTransformer

        public static <I,O> Transformer<I,O> switchTransformer(Predicate<? super I>[] predicates,
                                                       Transformer<? super I,? extends O>[] transformers,
                                                       Transformer<? super I,? extends O> defaultTransformer)
        Factory method that performs validation and copies the parameter arrays.
        Type Parameters:
        I - the input type
        O - the output type
        Parameters:
        predicates - array of predicates, cloned, no nulls
        transformers - matching array of transformers, cloned, no nulls
        defaultTransformer - the transformer to use if no match, null means return null
        Returns:
        the chained transformer
        Throws:
        NullPointerException - if array is null
        NullPointerException - if any element in the array is null

      • switchTransformer

        public static <I,O> Transformer<I,O> switchTransformer(Map<? extends Predicate<? super I>,? extends Transformer<? super I,? extends O>> map)
        Create a new Transformer that calls one of the transformers depending on the predicates.

        The Map consists of Predicate keys and Transformer values. A transformer is called if its matching predicate returns true. Each predicate is evaluated until one returns true. If no predicates evaluate to true, the default transformer is called. The default transformer is set in the map with a null key. The ordering is that of the iterator() method on the entryset collection of the map.

        Type Parameters:
        I - the input type
        O - the output type
        Parameters:
        map - a map of predicates to transformers
        Returns:
        the switch transformer
        Throws:
        NullPointerException - if the map is null
        NullPointerException - if any transformer in the map is null
        ClassCastException - if the map elements are of the wrong type

      • transform

        public O transform(I input)
        Transforms the input to result by calling the transformer whose matching predicate returns true.
        Specified by:
        transform in interface  Transformer<I,O>
        Parameters:
        input - the input object to transform
        Returns:
        the transformed result

      • getPredicates

        public Predicate<? super I>[] getPredicates()
        Gets the predicates.
        Returns:
        a copy of the predicates
        Since:
        3.1

      • getTransformers

        public Transformer<? super I,? extends O>[] getTransformers()
        Gets the transformers.
        Returns:
        a copy of the transformers
        Since:
        3.1

      • getDefaultTransformer

        public Transformer<? super I,? extends O> getDefaultTransformer()
        Gets the default transformer.
        Returns:
        the default transformer
        Since:
        3.1