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Oracle® Coherence Java API Reference
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## com.tangosol.util
Interface ValueExtractor

All Known Implementing Classes:
  AbstractCompositeExtractor, AbstractExtractor, ChainedExtractor, ComparisonValueExtractor, EntryExtractor, IdentityExtractor, KeyExtractor, MultiExtractor, NullImplementation.NullValueExtractor, PofExtractor, ReflectionExtractor

    public interface ValueExtractor

ValueExtractor is used to both extract values (for example, for sorting or filtering) from an object, and to provide an identity for that extraction.

Important Note: all classes that implement ValueExtractor interface must explicitly implement the `hashCode()` and `equals()` methods in a way that is based solely on the object's serializable state.

Author:
  cp/gg 2002.10.31

Method Summary
`boolean` | `equals(java.lang.Object o)` Compare the ValueExtractor with another object to determine equality.
`java.lang.Object` | `extract(java.lang.Object oTarget)` Extract the value from the passed object.
`int` | `hashCode()` Determine a hash value for the ValueExtractor object according to the general `Object.hashCode()` contract.
`java.lang.String` | `toString()` Provide a human-readable description of this ValueExtractor object.

Method Detail

### extract

    java.lang.Object extract(java.lang.Object oTarget)

  Extract the value from the passed object. The returned value may be null. For intrinsic types, the returned value is expected to be a standard wrapper type in the same manner that reflection works; for example, `int` would be returned as a `java.lang.Integer`.

  Parameters:
    `oTarget` - an Object to retrieve the value from
  Returns:
    the extracted value as an Object; null is an acceptable value
  Throws:
    `java.lang.ClassCastException` - if this ValueExtractor is incompatible with the passed object to extract a value from and the implementation requires the passed object to be of a certain type
    `WrapperException` - if this ValueExtractor encounters an exception in the course of extracting the value
    `java.lang.IllegalArgumentException` - if this ValueExtractor cannot handle the passed object for any other reason; an implementor should include a descriptive message

### equals

    boolean equals(java.lang.Object o)

  Compare the ValueExtractor with another object to determine equality. Two ValueExtractor objects, ve1 and ve2 are considered equal iff `ve1.extract(o)` equals `ve2.extract(o)` for all values of `o`.

  Parameters:
    `o` - the reference object with which to compare
  Returns:
    true iff this ValueExtractor and the passed object are equivalent ValueExtractors

### hashCode

    int hashCode()

  Determine a hash value for the ValueExtractor object according to the general `Object.hashCode()` contract.

  Returns:
    an integer hash value for this ValueExtractor object

### toString

    java.lang.String toString()

  Provide a human-readable description of this ValueExtractor object.

  Returns:
    a human-readable description of this ValueExtractor object

Overview | Package | Class | Tree | Index | Help

Oracle® Coherence Java API Reference
v3.5.3
E15583-01
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