Package com.tangosol.util.processor

Class ExtractorProcessor<K,V,T,E>

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.processor.AbstractProcessor<K,V,E>
com.tangosol.util.processor.ExtractorProcessor<K,V,T,E>
All Implemented Interfaces:
ExternalizableLite, PortableObject, InvocableMap.EntryProcessor<K,V,E>, Serializable
public class ExtractorProcessor<K,V,T,E> extends AbstractProcessor<K,V,E> implements ExternalizableLite, PortableObject
ExtractorProcessor is an EntryProcessor implementations that extracts a value from an object cached in an InvocableMap. A common usage pattern is: 
   cache.invoke(oKey, new ExtractorProcessor(extractor));
which is functionally equivalent to the following operation: 
   extractor.extract(cache.get(oKey));
The major difference is that for clustered caches using the ExtractorProcessor could significantly reduce the amount of network traffic.

An alternative (and superior) approach would be to use the ReducerAggregator

Author:
gg 2005.11.30
See Also:

  • Field Details

    • m_extractor

      protected ValueExtractor<? super T,? extends E> m_extractor
      The underlying value extractor.

  • Constructor Details

    • ExtractorProcessor

      public ExtractorProcessor()
      Default constructor (necessary for the ExternalizableLite interface).

    • ExtractorProcessor

      public ExtractorProcessor(ValueExtractor<? super T,? extends E> extractor)
      Construct an ExtractorProcessor based on the specified ValueExtractor.
      Parameters:
      extractor - a ValueExtractor object; passing null is equivalent to using the IdentityExtractor

    • ExtractorProcessor

      public ExtractorProcessor(String sMethod)
      Construct an ExtractorProcessor for a given method name.
      Parameters:
      sMethod - a method name to make a ReflectionExtractor for; this parameter can also be a dot-delimited sequence of method names which would result in an ExtractorProcessor based on the ChainedExtractor that is based on an array of corresponding ReflectionExtractor objects

  • Method Details

    • process

      public E process(InvocableMap.Entry<K,V> entry)
      Process a Map.Entry object.

      Note: if this method throws an exception, all modifications to the supplied entry or any other entries retrieved via the BackingMapContext.getBackingMapEntry(java.lang.Object) API will be rolled back leaving all underlying values unchanged.

      Specified by:
      process in interface InvocableMap.EntryProcessor<K,V,T>
      Parameters:
      entry - the Entry to process
      Returns:
      the result of the processing, if any

    • equals

      public boolean equals(Object o)
      Compare the ExtractorProcessor with another object to determine equality.
      Overrides:
      equals in class Object
      Returns:
      true iff this ExtractorProcessor and the passed object are equivalent ExtractorProcessor objects

    • hashCode

      public int hashCode()
      Determine a hash value for the ExtractorProcessor object according to the general Object.hashCode() contract.
      Overrides:
      hashCode in class Object
      Returns:
      an integer hash value for this ExtractorProcessor object

    • toString

      public String toString()
      Return a human-readable description for this ExtractorProcessor.
      Overrides:
      toString in class Object
      Returns:
      a String description of the ExtractorProcessor

    • readExternal

      public void readExternal(DataInput in) throws 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:
      IOException - if an I/O exception occurs

    • writeExternal

      public void writeExternal(DataOutput out) throws 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:
      IOException - if an I/O exception occurs

    • readExternal

      public void readExternal(PofReader in) throws 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:
      IOException - if an I/O error occurs

    • writeExternal

      public void writeExternal(PofWriter out) throws 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:
      IOException - if an I/O error occurs