Constructor Detail

• TransformerUtils

  public TransformerUtils()

  This class is not normally instantiated.

Method Detail

• exceptionTransformer

  public static Transformer exceptionTransformer()

  Gets a transformer that always throws an exception. This could be useful during testing as a placeholder.

  Returns:

  the transformer

  See Also:

  ExceptionTransformer

• nullTransformer

  public static Transformer nullTransformer()

  Gets a transformer that always returns null.

  Returns:

  the transformer

  See Also:

  ConstantTransformer

• nopTransformer

  public static Transformer nopTransformer()

  Gets a transformer that returns the input object. The input object should be immutable to maintain the contract of Transformer (although this is not checked).

  Returns:

  the transformer

  See Also:

  NOPTransformer

• cloneTransformer

  public static Transformer cloneTransformer()

  Gets a transformer that returns a clone of the input object. The input object will be cloned using one of these techniques (in order):

  • public clone method
  • public copy constructor
  • serialization clone

  Returns:

  the transformer

  See Also:

  CloneTransformer

• constantTransformer

  public static Transformer constantTransformer​(Object constantToReturn)

  Creates a Transformer that will return the same object each time the transformer is used.

  Parameters:

  constantToReturn - the constant object to return each time in the transformer

  Returns:

  the transformer.

  See Also:

  ConstantTransformer

• asTransformer

  public static Transformer asTransformer​(Closure closure)

  Creates a Transformer that calls a Closure each time the transformer is used. The transformer returns the input object.

  Parameters:

  closure - the closure to run each time in the transformer, not null

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the closure is null

  See Also:

  ClosureTransformer

• asTransformer

  public static Transformer asTransformer​(Predicate predicate)

  Creates a Transformer that calls a Predicate each time the transformer is used. The transformer will return either Boolean.TRUE or Boolean.FALSE.

  Parameters:

  predicate - the predicate to run each time in the transformer, not null

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the predicate is null

  See Also:

  PredicateTransformer

• asTransformer

  public static Transformer asTransformer​(Factory factory)

  Creates a Transformer that calls a Factory each time the transformer is used. The transformer will return the value returned by the factory.

  Parameters:

  factory - the factory to run each time in the transformer, not null

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the factory is null

  See Also:

  FactoryTransformer

• chainedTransformer

  public static Transformer chainedTransformer​(Transformer transformer1,
                                               Transformer transformer2)

  Create a new Transformer that calls two transformers, passing the result of the first into the second.

  Parameters:

  transformer1 - the first transformer

  transformer2 - the second transformer

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if either transformer is null

  See Also:

  ChainedTransformer

• chainedTransformer

  public static Transformer chainedTransformer​(Transformer[] transformers)

  Create a new Transformer that calls each transformer in turn, passing the result into the next transformer.

  Parameters:

  transformers - an array of transformers to chain

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the transformers array is null

  IllegalArgumentException - if any transformer in the array is null

  See Also:

  ChainedTransformer

• chainedTransformer

  public static Transformer chainedTransformer​(Collection transformers)

  Create a new Transformer that calls each transformer in turn, passing the result into the next transformer. The ordering is that of the iterator() method on the collection.

  Parameters:

  transformers - a collection of transformers to chain

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the transformers collection is null

  IllegalArgumentException - if any transformer in the collection is null

  See Also:

  ChainedTransformer

• switchTransformer

  public static Transformer switchTransformer​(Predicate predicate,
                                              Transformer trueTransformer,
                                              Transformer falseTransformer)

  Create a new Transformer that calls one of two transformers depending on the specified predicate.

  Parameters:

  predicate - the predicate to switch on

  trueTransformer - the transformer called if the predicate is true

  falseTransformer - the transformer called if the predicate is false

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the predicate is null

  IllegalArgumentException - if either transformer is null

  See Also:

  SwitchTransformer

• switchTransformer

  public static Transformer switchTransformer​(Predicate[] predicates,
                                              Transformer[] transformers)

  Create a new Transformer that calls one of the transformers depending on the predicates. The transformer at array location 0 is called if the predicate at array location 0 returned true. Each predicate is evaluated until one returns true. If no predicates evaluate to true, null is returned.

  Parameters:

  predicates - an array of predicates to check

  transformers - an array of transformers to call

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the either array is null

  IllegalArgumentException - if the either array has 0 elements

  IllegalArgumentException - if any element in the arrays is null

  IllegalArgumentException - if the arrays are different sizes

  See Also:

  SwitchTransformer

• switchTransformer

  public static Transformer switchTransformer​(Predicate[] predicates,
                                              Transformer[] transformers,
                                              Transformer defaultTransformer)

  Create a new Transformer that calls one of the transformers depending on the predicates. The transformer at array location 0 is called if the predicate at array location 0 returned true. Each predicate is evaluated until one returns true. If no predicates evaluate to true, the default transformer is called. If the default transformer is null, null is returned.

  Parameters:

  predicates - an array of predicates to check

  transformers - an array of transformers to call

  defaultTransformer - the default to call if no predicate matches, null means return null

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the either array is null

  IllegalArgumentException - if the either array has 0 elements

  IllegalArgumentException - if any element in the arrays is null

  IllegalArgumentException - if the arrays are different sizes

  See Also:

  SwitchTransformer

• switchTransformer

  public static Transformer switchTransformer​(Map predicatesAndTransformers)

  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. If no default transformer is set, null will be returned in a default case. The ordering is that of the iterator() method on the entryset collection of the map.

  Parameters:

  predicatesAndTransformers - a map of predicates to transformers

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the map is null

  IllegalArgumentException - if the map is empty

  IllegalArgumentException - if any transformer in the map is null

  ClassCastException - if the map elements are of the wrong type

  See Also:

  SwitchTransformer

• switchMapTransformer

  public static Transformer switchMapTransformer​(Map objectsAndTransformers)

  Create a new Transformer that uses the input object as a key to find the transformer to call.

  The Map consists of object keys and Transformer values. A transformer is called if the input object equals the key. If there is no match, the default transformer is called. The default transformer is set in the map using a null key. If no default is set, null will be returned in a default case.

  Parameters:

  objectsAndTransformers - a map of objects to transformers

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the map is null

  IllegalArgumentException - if the map is empty

  IllegalArgumentException - if any transformer in the map is null

  See Also:

  SwitchTransformer

• instantiateTransformer

  public static Transformer instantiateTransformer()

  Gets a Transformer that expects an input Class object that it will instantiate.

  Returns:

  the transformer

  See Also:

  InstantiateTransformer

• instantiateTransformer

  public static Transformer instantiateTransformer​(Class[] paramTypes,
                                                   Object[] args)

  Creates a Transformer that expects an input Class object that it will instantiate. The constructor used is determined by the arguments specified to this method.

  Parameters:

  paramTypes - parameter types for the constructor, can be null

  args - the arguments to pass to the constructor, can be null

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the paramTypes and args don't match

  See Also:

  InstantiateTransformer

• mapTransformer

  public static Transformer mapTransformer​(Map map)

  Creates a Transformer that uses the passed in Map to transform the input object (as a simple lookup).

  Parameters:

  map - the map to use to transform the objects

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the map is null

  See Also:

  MapTransformer

• invokerTransformer

  public static Transformer invokerTransformer​(String methodName)

  Gets a Transformer that invokes a method on the input object. The method must have no parameters. If the input object is null, null is returned.

  For example, TransformerUtils.invokerTransformer("getName"); will call the getName/code> method on the input object to determine the transformer result.

  Parameters:

  methodName - the method name to call on the input object, may not be null

  Returns:

  the transformer

  Throws:

  IllegalArgumentException - if the methodName is null.

  See Also:

  InvokerTransformer