TransformerMap (Apache Commons Math 3.3 API)

org.apache.commons.math3.util

## Class TransformerMap

- java.lang.Object
- - org.apache.commons.math3.util.TransformerMap

- All Implemented Interfaces:
    Serializable, NumberTransformer

      public class TransformerMap
      extends Object
      implements NumberTransformer, Serializable

  This TansformerMap automates the transformation of mixed object types. It provides a means to set NumberTransformers that will be selected based on the Class of the object handed to the Maps `double transform(Object o)` method.
  Version:
    $Id: TransformerMap.java 1416643 2012-12-03 19:37:14Z tn $
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `TransformerMap()` Build a map containing only the default transformer.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Set<Class<?>>` | `classes()` Returns the Set of Classes used as keys in the map.
    `void` | `clear()` Clears all the Class to Transformer mappings.
    `boolean` | `containsClass(Class<?> key)` Tests if a Class is present in the TransformerMap.
    `boolean` | `containsTransformer(NumberTransformer value)` Tests if a NumberTransformer is present in the TransformerMap.
    `boolean` | `equals(Object other)`
    `NumberTransformer` | `getTransformer(Class<?> key)` Returns the Transformer that is mapped to a class if mapping is not present, this returns null.
    `int` | `hashCode()`
    `NumberTransformer` | `putTransformer(Class<?> key, NumberTransformer transformer)` Sets a Class to Transformer Mapping in the Map.
    `NumberTransformer` | `removeTransformer(Class<?> key)` Removes a Class to Transformer Mapping in the Map.
    `double` | `transform(Object o)` Attempts to transform the Object against the map of NumberTransformers.
    `Collection<NumberTransformer>` | `transformers()` Returns the Set of NumberTransformers used as values in the map.

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### TransformerMap

          public TransformerMap()

      Build a map containing only the default transformer.

  - ### Method Detail

    - #### containsClass

          public boolean containsClass(Class<?> key)

      Tests if a Class is present in the TransformerMap.
      Parameters:
        `key` - Class to check
      Returns:
        true|false

    - #### containsTransformer

          public boolean containsTransformer(NumberTransformer value)

      Tests if a NumberTransformer is present in the TransformerMap.
      Parameters:
        `value` - NumberTransformer to check
      Returns:
        true|false

    - #### getTransformer

          public NumberTransformer getTransformer(Class<?> key)

      Returns the Transformer that is mapped to a class if mapping is not present, this returns null.
      Parameters:
        `key` - The Class of the object
      Returns:
        the mapped NumberTransformer or null.

    - #### putTransformer

          public NumberTransformer putTransformer(Class<?> key,
                                         NumberTransformer transformer)

      Sets a Class to Transformer Mapping in the Map. If the Class is already present, this overwrites that mapping.
      Parameters:
        `key` - The Class
        `transformer` - The NumberTransformer
      Returns:
        the replaced transformer if one is present

    - #### removeTransformer

          public NumberTransformer removeTransformer(Class<?> key)

      Removes a Class to Transformer Mapping in the Map.
      Parameters:
        `key` - The Class
      Returns:
        the removed transformer if one is present or null if none was present.

    - #### clear

          public void clear()

      Clears all the Class to Transformer mappings.

    - #### classes

          public Set<Class<?>> classes()

      Returns the Set of Classes used as keys in the map.
      Returns:
        Set of Classes

    - #### transformers

          public Collection<NumberTransformer> transformers()

      Returns the Set of NumberTransformers used as values in the map.
      Returns:
        Set of NumberTransformers

    - #### transform

          public double transform(Object o)
                           throws MathIllegalArgumentException

      Attempts to transform the Object against the map of NumberTransformers. Otherwise it returns Double.NaN.
      Specified by:
        `transform` in interface `NumberTransformer`
      Parameters:
        `o` - the Object to be transformed.
      Returns:
        the double value of the Object.
      Throws:
        `MathIllegalArgumentException` - if the Object can not be transformed into a Double.
      See Also:
        `NumberTransformer.transform(java.lang.Object)`

    - #### equals

          public boolean equals(Object other)

      Overrides:
        `equals` in class `Object`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `Object`

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