Class SwitchTransformer<I,O>
java.lang.Object
org.apache.commons.collections4.functors.SwitchTransformer<I,O>
- All Implemented Interfaces:
Serializable
,Function<I,
,O> Transformer<I,
O>
Transformer implementation calls the transformer whose predicate returns true,
like a switch statement.
- Since:
- 3.0
- See Also:
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Constructor Summary
ConstructorDescriptionSwitchTransformer
(Predicate<? super I>[] predicates, Transformer<? super I, ? extends O>[] transformers, Transformer<? super I, ? extends O> defaultTransformer) Constructor that performs no validation. -
Method Summary
Modifier and TypeMethodDescriptionTransformer<? super I,
? extends O> Gets the default transformer.Gets the predicates.Transformer<? super I,
? extends O>[] Gets the transformers.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.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.Transforms the input to result by calling the transformer whose matching predicate returns true.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.apache.commons.collections4.Transformer
apply
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Constructor Details
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SwitchTransformer
public SwitchTransformer(Predicate<? super I>[] predicates, Transformer<? super I, ? extends O>[] transformers, Transformer<? super I, ? extends O> defaultTransformer) Constructor that performs no validation. UseswitchTransformer
if you want that.- Parameters:
predicates
- array of predicates, cloned, no nullstransformers
- matching array of transformers, cloned, no nullsdefaultTransformer
- the transformer to use if no match, null means return null
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Method Details
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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 typeO
- the output type- Parameters:
map
- a map of predicates to transformers- Returns:
- the
switch
transformer - Throws:
NullPointerException
- if the map is nullNullPointerException
- if any transformer in the map is nullClassCastException
- if the map elements are of the wrong type
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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 typeO
- the output type- Parameters:
predicates
- array of predicates, cloned, no nullstransformers
- matching array of transformers, cloned, no nullsdefaultTransformer
- the transformer to use if no match, null means return null- Returns:
- the
chained
transformer - Throws:
NullPointerException
- if either array is nullNullPointerException
- if any element in the arrays is nullIllegalArgumentException
- if the arrays have different sizes
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getDefaultTransformer
Gets the default transformer.- Returns:
- the default transformer
- Since:
- 3.1
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getPredicates
Gets the predicates.- Returns:
- a copy of the predicates
- Since:
- 3.1
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getTransformers
Gets the transformers.- Returns:
- a copy of the transformers
- Since:
- 3.1
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transform
Transforms the input to result by calling the transformer whose matching predicate returns true.- Specified by:
transform
in interfaceTransformer<I,
O> - Parameters:
input
- the input object to transform- Returns:
- the transformed result
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