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HSQLDB example source code file (CachedDataRow.java)
The HSQLDB CachedDataRow.java source code/* Copyright (c) 2001-2008, The HSQL Development Group * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the HSQL Development Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package org.hsqldb; import java.io.IOException; import org.hsqldb.rowio.RowInputInterface; import org.hsqldb.rowio.RowOutputInterface; // fredt@users 20021205 - path 1.7.2 - enhancements // fredt@users 20021215 - doc 1.7.2 - javadoc comments /** * Implementation of rows for tables with memory resident indexes and * disk-based data, such as TEXT tables. * * @version 1.7.2 */ class CachedDataRow extends CachedRow { /** * Constructor for new rows. */ CachedDataRow(Table t, Object[] o) throws HsqlException { super(t, o); hasDataChanged = true; } /** * Constructor when read from the disk into the Cache. The link with * the Nodes is made separetly. */ CachedDataRow(Table t, RowInputInterface in) throws IOException, HsqlException { tTable = t; iPos = in.getPos(); storageSize = in.getSize(); oData = in.readData(tTable.getColumnTypes()); hasDataChanged = false; } /** * As the indexes are in-memory, this passes the existing primary node * for the construction of the new Row */ Row getUpdatedRow() throws HsqlException { return tTable.getRow(iPos, nPrimaryNode); } /** * Used when data is read from the disk into the Cache the first time. * New Nodes are created which are then indexed. */ void setNewNodes() { int index = tTable.getIndexCount(); nPrimaryNode = Node.newNode(this, 0, tTable); Node n = nPrimaryNode; for (int i = 1; i < index; i++) { n.nNext = Node.newNode(this, i, tTable); n = n.nNext; } } /** * Used when data is re-read from the disk into the Cache. The Row is * already indexed so it is linked with the Node in the primary index. * the Nodes is made separetly. */ void setPrimaryNode(Node primary) { nPrimaryNode = primary; } /** * returned size does not include the row size written at the beginning */ public int getRealSize(RowOutputInterface out) { return out.getSize(this); } /** * Writes the data to disk. Unlike CachedRow, hasChanged is never set * to true when changes are made to the Nodes. (Nodes are in-memory). * The only time this is used is when a new Row is added to the Caches. */ public void write(RowOutputInterface out) { out.writeSize(storageSize); out.writeData(oData, tTable); out.writeEnd(); hasDataChanged = false; } public boolean hasChanged() { return hasDataChanged; } /** * Sets the file position for the row and registers the row with * the table. * * @param pos position in data file */ public void setPos(int pos) { iPos = pos; Node n = nPrimaryNode; while (n != null) { ((PointerNode) n).iData = iPos; n = n.nNext; } } /** * With the current implementation of TEXT table updates and inserts, * the lifetime scope of this method extends until redefinition of table * data source or shutdown. * * @param obj the reference object with which to compare. * @return <code>true if this object is the same as the obj argument; * <code>false otherwise. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (obj instanceof CachedDataRow) { return ((CachedDataRow) obj).iPos == iPos && ((CachedDataRow) obj).tTable == tTable; } return false; } } Other HSQLDB examples (source code examples)Here is a short list of links related to this HSQLDB CachedDataRow.java source code file: |
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