Class UpdaterProcessor<K,V,T>

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.processor.AbstractProcessor<K,V,Boolean>
com.tangosol.util.processor.UpdaterProcessor<K,V,T>
All Implemented Interfaces:
ExternalizableLite, PortableObject, InvocableMap.EntryProcessor<K,V,Boolean>, Serializable
public class UpdaterProcessor<K,V,T> extends AbstractProcessor<K,V,Boolean> implements ExternalizableLite, PortableObject
UpdaterProcessor is an EntryProcessor implementations that updates an attribute of an object cached in an InvocableMap. A common usage pattern is: 
  cache.invoke(oKey, new UpdaterProcessor(updater, value));
which is functionally equivalent to the following operation: 
  V target = cache.get(key);
  updater.update(target, value);
  cache.put(key, target);
The major difference is that for clustered caches using the UpdaterProcessor allows avoiding explicit concurrency control and could significantly reduce the amount of network traffic.
Author:
gg 2006.07.25
See Also:

  • Field Details

    • m_updater

      protected ValueUpdater<V,T> m_updater
      The underlying ValueUpdater.

    • m_value

      protected T m_value
      A value to update the entry's value with.

  • Constructor Details

    • UpdaterProcessor

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

    • UpdaterProcessor

      public UpdaterProcessor(ValueUpdater<V,T> updater, T value)
      Construct an UpdaterProcessor based on the specified ValueUpdater.
      Parameters:
      updater - a ValueUpdater object; passing null will simpy replace the entry's value with the specified one instead of updating it
      value - the value to update the target entry with

    • UpdaterProcessor

      public UpdaterProcessor(String sMethod, T value)
      Construct an UpdaterProcessor for a given method name. The method must have a single parameter of a Java type compatible with the specified value type.
      Parameters:
      sMethod - a method name to make a ReflectionUpdater for; this parameter can also be a dot-delimited sequence of method names which would result in using a CompositeUpdater
      value - the value to update the target entry with

  • Method Details

    • process

      public Boolean 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(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

    • getValueUpdater

      public ValueUpdater<V,T> getValueUpdater()
      Return the nested value updater used by this processor.
      Returns:
      the nested value updater

    • equals

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

    • hashCode

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

    • toString

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

    • 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