/* * JBoss, Home of Professional Open Source. * See the COPYRIGHT.txt file distributed with this work for information * regarding copyright ownership. Some portions may be licensed * to Red Hat, Inc. under one or more contributor license agreements. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301 USA. */ package org.teiid.common.buffer; import java.util.List; import org.teiid.core.TeiidComponentException; import org.teiid.core.TeiidProcessingException; public abstract class AbstractTupleSource implements IndexedTupleSource { private long currentRow = 1; private long mark = 1; protected List<?> currentTuple; protected TupleBatch batch; @Override public long getCurrentIndex() { return this.currentRow; } @Override public List<?> nextTuple() throws TeiidComponentException, TeiidProcessingException{ List<?> result = null; if (currentTuple != null){ result = currentTuple; currentTuple = null; } else { result = getCurrentTuple(); } if (result != null) { currentRow++; } return result; } protected List<?> getCurrentTuple() throws TeiidComponentException, BlockedException, TeiidProcessingException { if (available() > 0) { //if (forwardOnly) { long row = getCurrentIndex(); if (batch == null || !batch.containsRow(row)) { batch = getBatch(row); } return batch.getTuple(row); //} //TODO: determine if we should directly hold a soft reference here //return getRow(currentRow); } batch = null; return finalRow(); } protected abstract List<?> finalRow() throws BlockedException, TeiidComponentException, TeiidProcessingException; protected abstract TupleBatch getBatch(long row) throws TeiidComponentException, TeiidProcessingException; protected abstract long available(); @Override public void closeSource() { batch = null; mark = 1; reset(); } @Override public boolean hasNext() throws TeiidComponentException, TeiidProcessingException { if (this.currentTuple != null) { return true; } this.currentTuple = getCurrentTuple(); return this.currentTuple != null; } @Override public void reset() { this.setPosition(mark); this.mark = 1; } @Override public void mark() throws TeiidComponentException { this.mark = currentRow; } @Override public void setPosition(long position) { if (this.currentRow != position) { this.currentRow = position; this.currentTuple = null; } } }