org.apache.cayenne.access.jdbc
Class DistinctResultIterator<T>

java.lang.Object
  extended by org.apache.cayenne.access.jdbc.DistinctResultIterator<T>
All Implemented Interfaces:
Iterable<T>, ResultIterator<T>

public class DistinctResultIterator<T>
extends Object
implements ResultIterator<T>

A ResultIterator that does in-memory filtering of rows to return only distinct rows. Distinct comparison is done by comparing ObjectIds created from each row. Internally DistinctResultIterator wraps another ResultIterator that provides the actual rows.

Since:
3.0

Field Summary
protected  boolean compareFullRows
           
protected  DbEntity defaultEntity
           
protected  ResultIterator<T> delegate
           
protected  Set<Map<String,Object>> fetchedIds
           
protected  DataRow nextDataRow
           
 
Constructor Summary
DistinctResultIterator(ResultIterator<T> delegate, DbEntity defaultEntity, boolean compareFullRows)
          Creates new DistinctResultIterator wrapping another ResultIterator.
 
Method Summary
 List<T> allRows()
          Returns all yet unread rows from ResultSet without closing it.
 void close()
          CLoses underlying ResultIterator.
 boolean hasNextRow()
          Returns true if there is at least one more record that can be read from the iterator.
 Iterator<T> iterator()
           
 T nextRow()
          Returns the next result row that is, depending on the query, may be a scalar value, a DataRow, or an Object[] array containing a mix of scalars and DataRows.
 void skipRow()
          Goes past current row.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

delegate

protected ResultIterator<T> delegate

fetchedIds

protected Set<Map<String,Object>> fetchedIds

nextDataRow

protected DataRow nextDataRow

defaultEntity

protected DbEntity defaultEntity

compareFullRows

protected boolean compareFullRows
Constructor Detail

DistinctResultIterator

public DistinctResultIterator(ResultIterator<T> delegate,
                              DbEntity defaultEntity,
                              boolean compareFullRows)
Creates new DistinctResultIterator wrapping another ResultIterator.

Parameters:
wrappedIterator -
defaultEntity - an entity needed to build ObjectIds for distinct comparison.
Method Detail

iterator

public Iterator<T> iterator()
Specified by:
iterator in interface Iterable<T>
Since:
3.2

close

public void close()
CLoses underlying ResultIterator.

Specified by:
close in interface ResultIterator<T>

allRows

public List<T> allRows()
Description copied from interface: ResultIterator
Returns all yet unread rows from ResultSet without closing it.

Specified by:
allRows in interface ResultIterator<T>
Since:
3.0

hasNextRow

public boolean hasNextRow()
Description copied from interface: ResultIterator
Returns true if there is at least one more record that can be read from the iterator.

Specified by:
hasNextRow in interface ResultIterator<T>

nextRow

public T nextRow()
Description copied from interface: ResultIterator
Returns the next result row that is, depending on the query, may be a scalar value, a DataRow, or an Object[] array containing a mix of scalars and DataRows.

Specified by:
nextRow in interface ResultIterator<T>

skipRow

public void skipRow()
Description copied from interface: ResultIterator
Goes past current row. If the row is not needed, this may save some time on data conversion.

Specified by:
skipRow in interface ResultIterator<T>
Since:
3.0


Copyright © 2001-2013 Apache Cayenne. All Rights Reserved.