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// This Source Code is in the Public Domain per: http://litesoft.org/License.txt package org.litesoft.orsup.nonpublic; import java.util.*; import org.litesoft.orsup.base.*; public abstract class AbstractPOKeyIterator extends POKeyIterator { private POKeyQueryFilter mPOKeyQueryFilter; private PersistenceHelperRowSource mRowSource; private Object mPreFetchedKey = null; protected AbstractPOKeyIterator( POKeyQueryFilter pPOKeyQueryFilter, PersistenceHelperRowSource pRowSource ) { mPOKeyQueryFilter = pPOKeyQueryFilter; mRowSource = PersistenceHelperRowSource.NULL.deNull( pRowSource ); try { if ( POQueryFilter.TYPE.NoneAcceptable.equals( pPOKeyQueryFilter.getType() ) ) { releaseRowSource(); return; } mRowSource = mRowSource.prepareForGetNextRow(); mPreFetchedKey = preFetchKey(); } catch ( RuntimeException e ) { releaseResources(); throw e; } } private void releaseRowSource() { mRowSource.dispose(); mRowSource = PersistenceHelperRowSource.NULL.INSTANCE; } private Object preFetchKey() { for ( Object[] row; null != (row = mRowSource.getNextRow()); ) { Object zKey = row[0]; if ( mPOKeyQueryFilter.isPO_KeyAcceptable( zKey ) ) { return zKey; } } releaseRowSource(); return null; } @Override public void releaseResources() { releaseRowSource(); super.releaseResources(); } @Override public final boolean hasNext() { return (mPreFetchedKey != null); } @Override public final Object next() { if ( !hasNext() ) { throw new NoSuchElementException(); } try { Object rv = mPreFetchedKey; mPreFetchedKey = preFetchKey(); return rv; } catch ( RuntimeException e ) { releaseResources(); throw e; } } } |