Package wt.impact

Class WTEntryChunkedIterator

java.lang.Object
wt.impact.AbstractWTEntryChunkedIterator<WTKeyedMap.WTEntry>
wt.impact.WTEntryChunkedIterator
All Implemented Interfaces:
AutoCloseable, Iterator<WTKeyedMap.WTEntry>
public class WTEntryChunkedIterator extends AbstractWTEntryChunkedIterator<WTKeyedMap.WTEntry>
WTKeyedMap entry set iterator that inflates and deflates key references in chunks. This iterator keeps memory usage low when iterating over large, deflated maps.

This iterator can only be used in the method server.

It is recommended that this iterator be used as resource in a try-with-resources block to ensure that inflated key references are deflated if iteration terminates.

Examples: 

 WTKeyedMap wtMap;
     :
 // wtMap is created and populated with deflated key references
     :
 try (WTEntryChunkedIterator entryIter = new WTEntryChunkedIterator(wtMap, 1000)) {
     while ( entryIter.hasNext() ) {
         WTEntry entry = entryIter.next();  // Key references are inflated.
             :
     }
 }
 // All key references in the map that were originally deflated will be 
 // automatically deflated when the try-with-resources block exits.
 // All key references in the map that were originally inflated will remain so.
     :
If a try-with-resources block is not used then AbstractWTEntryChunkedIterator.close() should be called when the iterator is no longer needed: 
 WTKeyedMap wtMap;
     :
 // wtMap is created and populated with deflated key references
     :
 WTEntryChunkedIterator entryIter = new WTEntryChunkedIterator(wtMap, 1000);
 while ( entryIter.hasNext() ) {
     WTEntry entry = entryIter.next();  // Key references are inflated.
         :
 }
 entryIter.close(); // Deflate key references.
     :


Supported API: true

Extendable: false

  • Constructor Details

    • WTEntryChunkedIterator

      public WTEntryChunkedIterator(WTKeyedMap map, int chunkSize)
      Construct a new WTEntryChunkedIterator for all map entries. Inflates key references in chunks to keep memory usage low.

      This iterator can only be used in the method server.

      Supported API: true

      Parameters:
      map - WTKeyedMap with deflated key references.
      chunkSize - Number of entries that are inflated in a chunk.

    • WTEntryChunkedIterator

      public WTEntryChunkedIterator(WTKeyedMap map, int chunkSize, Class<? extends Persistable> keyFilter)
      Construct a new WTEntryChunkedIterator for map entries with filtered keys and all key sub-classes. Inflates key references in chunks to keep memory usage low.

      This iterator can only be used in the method server.

      Supported API: true

      Parameters:
      map - WTKeyedMap with deflated key references.
      chunkSize - Number of entries that are inflated in a chunk.
      keyFilter - Key class filter.

    • WTEntryChunkedIterator

      public WTEntryChunkedIterator(WTKeyedMap map, int chunkSize, Class<? extends Persistable> keyFilter, boolean includeSubclasses)
      Construct a new WTEntryChunkedIterator for map entries with filtered keys. Inflates key references in chunks to keep memory usage low.

      This iterator can only be used in the method server.

      Supported API: true

      Parameters:
      map - WTKeyedMap with deflated key references.
      chunkSize - Number of entries that are inflated in a chunk.
      keyFilter - Key class filter.
      includeSubclasses - True to iterated over the key filter objects and all of its sub-classes, or false to iterated over only the key filter objects.