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## com.tangosol.util.extractor
Class EntryExtractor

`java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.util.extractor.AbstractExtractor
com.tangosol.util.extractor.EntryExtractor`

All Implemented Interfaces:
  ExternalizableLite, PortableObject, QueryMapComparator, ValueExtractor, java.io.Serializable, java.util.Comparator

      public abstract class EntryExtractor

extends AbstractExtractor
implements PortableObject, ExternalizableLite

The EntryExtractor is a base abstract class for special purpose custom ValueExtractor implementations. It allows them to extract a desired value using all available information on the corresponding Map.Entry object and is intended to be used in advanced custom scenarios, when application code needs to look at both key and value at the same time or can make some very specific assumptions regarding to the implementation details of the underlying Entry object. As of Coherence 3.5, the same behavior can be achieved by subclasses of the AbstractExtractor by overriding the `AbstractExtractor.extractFromEntry()`.

Since:
  Coherence 3.4
Author:
  gg 2008.04.14

Field Summary

Fields inherited from class com.tangosol.util.extractor.AbstractExtractor
`KEY, m_nTarget, VALUE`

Constructor Summary
`EntryExtractor()` Default constructor (for backward compatibilty).
`EntryExtractor(int nTarget)` Construct an EntryExtractor based on the entry extraction target.

Method Summary
`void` | `readExternal(java.io.DataInput in)` Restore the contents of this object by loading the object's state from the passed DataInput object.
`void` | `readExternal(PofReader in)` Restore the contents of a user type instance by reading its state using the specified PofReader object.
`void` | `writeExternal(java.io.DataOutput out)` Save the contents of this object by storing the object's state into the passed DataOutput object.
`void` | `writeExternal(PofWriter out)` Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Methods inherited from class com.tangosol.util.extractor.AbstractExtractor
`compare, compareEntries, extract, extractFromEntry, extractOriginalFromEntry`

Methods inherited from class com.tangosol.util.BitHelper
`countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, rotateLeft, rotateLeft, rotateLeft, rotateRight, rotateRight, rotateRight, toBitString, toBitString, toBitString`

Methods inherited from interface com.tangosol.util.ValueExtractor
`equals, hashCode, toString`

Methods inherited from interface java.util.Comparator
`equals`

Constructor Detail

### EntryExtractor

    public EntryExtractor()

  Default constructor (for backward compatibilty).

### EntryExtractor

    public EntryExtractor(int nTarget)

  Construct an EntryExtractor based on the entry extraction target.
  Parameters:
    `nTarget` - one of the `AbstractExtractor.VALUE` or `AbstractExtractor.KEY` values
  Since:
    Coherence 3.5

Method Detail

### readExternal

    public void readExternal(java.io.DataInput in)
                      throws java.io.IOException

  Restore the contents of this object by loading the object's state from the passed DataInput object.
  Specified by:
    `readExternal` in interface `ExternalizableLite`
  Parameters:
    `in` - the DataInput stream to read data from in order to restore the state of this object
  Throws:
    `java.io.IOException` - if an I/O exception occurs
    `java.io.NotActiveException` - if the object is not in its initial state, and therefore cannot be deserialized into

### writeExternal

    public void writeExternal(java.io.DataOutput out)
                       throws java.io.IOException

  Save the contents of this object by storing the object's state into the passed DataOutput object.
  Specified by:
    `writeExternal` in interface `ExternalizableLite`
  Parameters:
    `out` - the DataOutput stream to write the state of this object to
  Throws:
    `java.io.IOException` - if an I/O exception occurs

### readExternal

    public void readExternal(PofReader in)
                      throws java.io.IOException

  Restore the contents of a user type instance by reading its state using the specified PofReader object.
  Specified by:
    `readExternal` in interface `PortableObject`
  Parameters:
    `in` - the PofReader from which to read the object's state
  Throws:
    `java.io.IOException` - if an I/O error occurs

### writeExternal

    public void writeExternal(PofWriter out)
                       throws java.io.IOException

  Save the contents of a POF user type instance by writing its state using the specified PofWriter object.
  Specified by:
    `writeExternal` in interface `PortableObject`
  Parameters:
    `out` - the PofWriter to which to write the object's state
  Throws:
    `java.io.IOException` - if an I/O error occurs

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