/* Copyright (c) 2001-2010, 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
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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package org.hsqldb.navigator;
import java.io.IOException;
import java.util.NoSuchElementException;
import org.hsqldb.Row;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.HsqlLinkedList;
import org.hsqldb.lib.HsqlLinkedList.Node;
import org.hsqldb.result.ResultMetaData;
import org.hsqldb.rowio.RowInputInterface;
import org.hsqldb.rowio.RowOutputInterface;
/*
* All-in-memory implementation of RowSetNavigator for simple client or server
* side result sets. These are the result sets used for batch or other internal
* operations.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 1.9.0
* @since 1.9.0
*/
public class RowSetNavigatorLinkedList extends RowSetNavigator {
HsqlLinkedList list;
final Node root;
Node previous;
Node current;
public RowSetNavigatorLinkedList() {
list = new HsqlLinkedList();
root = list.getHeadNode();
current = root;
}
/**
* Returns the current row object.
*/
public Object[] getCurrent() {
return ((Row) current.data).getData();
}
public Row getCurrentRow() {
return (Row) current.data;
}
public Row getNextRow() {
return next() ? (Row) current.data
: null;
}
public void remove() {
// avoid consecutive removes without next()
if (previous == null) {
throw new NoSuchElementException();
}
if (currentPos < size && currentPos != -1) {
list.removeAfter(previous);
current = previous;
size--;
currentPos--;
return;
}
throw new NoSuchElementException();
}
public boolean next() {
boolean result = super.next();
if (result) {
previous = current;
current = current.next;
}
return result;
}
public void reset() {
super.reset();
current = root;
previous = null;
}
// reading and writing
public void write(RowOutputInterface out,
ResultMetaData meta) throws IOException {
beforeFirst();
out.writeLong(id);
out.writeInt(size);
out.writeInt(0); // offset
out.writeInt(size);
while (hasNext()) {
Object[] data = getNext();
out.writeData(meta.getColumnCount(), meta.columnTypes, data, null,
null);
}
beforeFirst();
}
public void read(RowInputInterface in,
ResultMetaData meta) throws IOException {
id = in.readLong();
int count = in.readInt();
in.readInt(); // offset
in.readInt(); // size again
while (count-- > 0) {
add(in.readData(meta.columnTypes));
}
}
public void clear() {
reset();
list.clear();
size = 0;
}
/**
* Method declaration
*
* @param d
*/
public void add(Object[] d) {
throw Error.runtimeError(ErrorCode.U_S0500, "RowSetNavigatorClient");
}
public boolean addRow(Row row) {
list.add(row);
size++;
return true;
}
}