ehcache

net.sf.ehcache.search
Class NullResults

java.lang.Object
  extended by net.sf.ehcache.search.NullResults
All Implemented Interfaces:
Results

public class NullResults
extends Object
implements Results

An empty result instance

Author:
teck

Field Summary
static NullResults INSTANCE
          A global instance that can be freely shared with the world since this type has no state
 
Constructor Summary
NullResults()
           
 
Method Summary
 List<Result> all()
          Retrieve all of the cache results in one shot.
 void discard()
          Discard this query result.
 boolean hasAggregators()
          Whether the results contains aggregates
 boolean hasAttributes()
          Whether the Results have cache attributes included.
 boolean hasKeys()
          Whether the Results have cache keys included.
 boolean hasValues()
          Whether the Results have cache values included.
 List<Result> range(int start, int count)
          Retrieve a subset of the cache results.
 int size()
          Results size
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

INSTANCE

public static final NullResults INSTANCE
A global instance that can be freely shared with the world since this type has no state

Constructor Detail

NullResults

public NullResults()
Method Detail

discard

public void discard()
Discard this query result. This call is not mandatory but is recommended after the caller is done with results. It can allow the cache, which may be distributed, to immediately free any resources associated with this result.

Multiple calls are ignored. Attempting to read results from this instance after this method has been called will produce SearchException

Specified by:
discard in interface Results

all

public List<Result> all()
                 throws SearchException
Retrieve all of the cache results in one shot. For large result sets this might consume large amount of memory

Specified by:
all in interface Results
Returns:
a List of all the matching cache entries
Throws:
SearchException

range

public List<Result> range(int start,
                          int count)
                   throws SearchException,
                          IndexOutOfBoundsException
Retrieve a subset of the cache results. This method is useful when showing "paged" results in a user interface or simply to keep memory overhead fixed

Specified by:
range in interface Results
Parameters:
start - starting index to access
count - the number of results to return
Returns:
a List of the given size. This list will be smaller than the requested size if no more results are available. If there are no more results an empty list will be returned.
Throws:
SearchException
IndexOutOfBoundsException

size

public int size()
Results size

Specified by:
size in interface Results
Returns:
number of results present

hasKeys

public boolean hasKeys()
Whether the Results have cache keys included. If so these can be extracted from the Result object.

Specified by:
hasKeys in interface Results
Returns:
true if keys are included

hasValues

public boolean hasValues()
Whether the Results have cache values included. If so these can be extracted from the Result object.

Specified by:
hasValues in interface Results
Returns:
true if values are included

hasAttributes

public boolean hasAttributes()
Whether the Results have cache attributes included. If so these can be extracted from the Result object.

Specified by:
hasAttributes in interface Results
Returns:
true if attributes are included

hasAggregators

public boolean hasAggregators()
Whether the results contains aggregates

Specified by:
hasAggregators in interface Results
Returns:
true if this is an aggregate

ehcache

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