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HSQLDB - Lightweight 100% Java SQL Database Engine
/* Copyright (c) 2001-2019, 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.navigator;
import org.hsqldb.HsqlException;
import org.hsqldb.Row;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.result.ResultMetaData;
import org.hsqldb.rowio.RowInputInterface;
import org.hsqldb.rowio.RowOutputInterface;
/*
* All-in-memory implementation of RowSetNavigator for client side, or for
* transferring a slice of the result to the client or server using a subset of
* a server-side row set.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.3.5
* @since 1.9.0
*/
public class RowSetNavigatorClient extends RowSetNavigator {
public static final Object[][] emptyTable = new Object[0][];
//
int currentOffset;
int baseBlockSize;
//
Object[][] table;
//
public RowSetNavigatorClient() {
table = emptyTable;
}
public RowSetNavigatorClient(int blockSize) {
table = new Object[blockSize][];
}
public RowSetNavigatorClient(RowSetNavigator source, int offset,
int blockSize) {
this.size = source.size;
this.baseBlockSize = blockSize;
this.currentOffset = offset;
table = new Object[blockSize][];
source.absolute(offset);
for (int count = 0; count < blockSize; count++) {
table[count] = source.getCurrent();
source.next();
}
source.beforeFirst();
}
/**
* For communication of small results such as BATCHEXECRESPONSE
*/
public void setData(Object[][] table) {
this.table = table;
this.size = table.length;
}
public void setData(int index, Object[] data) {
table[index] = data;
}
public Object[] getData(int index) {
return table[index];
}
/**
* Returns the current row object. Type of object is implementation defined.
*/
public Object[] getCurrent() {
if (currentPos < 0 || currentPos >= size) {
return null;
}
if (currentPos >= currentOffset + table.length) {
getBlock(currentOffset + table.length);
}
return table[currentPos - currentOffset];
}
public Row getCurrentRow() {
throw Error.runtimeError(ErrorCode.U_S0500, "RowSetNavigatorClient");
}
/**
* Only for navigators for INSERT
*/
public void removeCurrent() {
System.arraycopy(table, currentPos + 1, table, currentPos,
size - currentPos - 1);
table[size - 1] = null;
currentPos--;
size--;
}
public void add(Object[] data) {
ensureCapacity();
table[size] = data;
size++;
}
public boolean addRow(Row row) {
throw Error.runtimeError(ErrorCode.U_S0500, "RowSetNavigatorClient");
}
public void clear() {
setData(emptyTable);
size = 0;
reset();
}
public void release() {
setData(emptyTable);
reset();
isClosed = true;
}
public boolean absolute(int position) {
if (position < 0) {
position += size;
}
if (position < 0) {
beforeFirst();
return false;
}
if (position >= size) {
afterLast();
return false;
}
if (size == 0) {
return false;
}
currentPos = position;
return true;
}
public void readSimple(RowInputInterface in, ResultMetaData meta) {
size = in.readInt();
if (table.length < size) {
table = new Object[size][];
}
for (int i = 0; i < size; i++) {
table[i] = in.readData(meta.columnTypes);
}
}
public void writeSimple(RowOutputInterface out, ResultMetaData meta) {
out.writeInt(size);
for (int i = 0; i < size; i++) {
Object[] data = table[i];
out.writeData(meta.getColumnCount(), meta.columnTypes, data, null,
null);
}
}
public void read(RowInputInterface in, ResultMetaData meta) {
id = in.readLong();
size = in.readInt();
currentOffset = in.readInt();
baseBlockSize = in.readInt();
if (table.length < baseBlockSize) {
table = new Object[baseBlockSize][];
}
for (int i = 0; i < baseBlockSize; i++) {
table[i] = in.readData(meta.columnTypes);
}
}
public void write(RowOutputInterface out, ResultMetaData meta) {
int limit = size - currentOffset;
if (limit > table.length) {
limit = table.length;
}
out.writeLong(id);
out.writeInt(size);
out.writeInt(currentOffset);
out.writeInt(limit);
for (int i = 0; i < limit; i++) {
Object[] data = table[i];
out.writeData(meta.getColumnCount(), meta.columnTypes, data, null,
null);
}
}
/**
* baseBlockSize remains unchanged.
*/
void getBlock(int offset) {
try {
RowSetNavigatorClient source = session.getRows(id, offset,
baseBlockSize);
table = source.table;
currentOffset = source.currentOffset;
} catch (HsqlException e) {}
}
private void ensureCapacity() {
if (size == table.length) {
int newSize = size == 0 ? 4
: size * 2;
Object[][] newTable = new Object[newSize][];
System.arraycopy(table, 0, newTable, 0, size);
table = newTable;
}
}
}