Package com.tangosol.util.processor

Class PreloadRequest<K,V>

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.processor.AbstractProcessor<K,V,V>
com.tangosol.util.processor.PreloadRequest<K,V>
All Implemented Interfaces:
ExternalizableLite, PortableObject, InvocableMap.EntryProcessor<K,V,V>, Serializable
public class PreloadRequest<K,V> extends AbstractProcessor<K,V,V> implements ExternalizableLite, PortableObject
PreloadRequest is a simple EntryProcessor that performs a Entry.getValue call. No results are reported back to the caller.

The PreloadRequest process provides a means to "pre-load" an entry or a collection of entries into the cache using the cache loader without incurring the cost of sending the value(s) over the network. If the corresponding entry (or entries) already exists in the cache, or if the cache does not have a loader, then invoking this EntryProcessor has no effect.

Since:
Coherence 3.2
Author:
gg 2006.04.28
See Also:

  • Field Details

    • INSTANCE

      public static final PreloadRequest INSTANCE
      An instance of the PreloadRequest processor.

  • Constructor Details

    • PreloadRequest

      public PreloadRequest()
      Construct the PreloadRequest processor.

  • Method Details

    • process

      public V 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,V>
      Parameters:
      entry - the Entry to process
      Returns:
      the result of the processing, if any

    • processAll

      public Map<K,V> processAll(Set<? extends InvocableMap.Entry<K,V>> setEntries)
      Process a Set of InvocableMap.Entry objects. This method is semantically equivalent to: 
         Map mapResults = new ListMap();
   for (Iterator iter = setEntries.iterator(); iter.hasNext(); )
       {
       Entry entry = (Entry) iter.next();
       mapResults.put(entry.getKey(), process(entry));
       }
   return mapResults;

      Note: if processAll() call throws an exception, only the entries that were removed from the setEntries would be considered successfully processed and the corresponding changes made to the underlying Map; changes made to the remaining entries or any other entries obtained from BackingMapContext.getBackingMapEntry(java.lang.Object) will not be processed. Note: As of Coherence 12.2.1, this method simply delegates to the default processAll implementation in InvocableMap.EntryProcessor.

      Specified by:
      processAll in interface InvocableMap.EntryProcessor<K,V,V>
      Overrides:
      processAll in class AbstractProcessor<K,V,V>
      Parameters:
      setEntries - a Set of InvocableMap.Entry objects to process
      Returns:
      a Map containing the results of the processing, up to one entry for each InvocableMap.Entry that was processed, keyed by the keys of the Map that were processed, with a corresponding value being the result of the processing for each key

    • equals

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

    • hashCode

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

    • toString

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

    • 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

    • INSTANCE

      public static <K, V> PreloadRequest<K,V> INSTANCE()
      Return an instance of the PreloadRequest processor.
      Type Parameters:
      K - the key type
      V - the value type
      Returns:
      a PreloadRequest