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/*
Copyright (c) 2007 Health Market Science, Inc.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA
You can contact Health Market Science at info@healthmarketscience.com
or at the following address:
Health Market Science
2700 Horizon Drive
Suite 200
King of Prussia, PA 19406
*/
package com.healthmarketscience.jackcess;
import org.apache.commons.lang.builder.CompareToBuilder;
/**
* Uniquely identifies a row of data within the access database.
*
* @author James Ahlborn
*/
public class RowId implements Comparable<RowId>
{
/** special page number which will sort before any other valid page
number */
public static final int FIRST_PAGE_NUMBER = -1;
/** special page number which will sort after any other valid page
number */
public static final int LAST_PAGE_NUMBER = -2;
/** special row number representing an invalid row number */
public static final int INVALID_ROW_NUMBER = -1;
/** type attributes for RowIds which simplify comparisons */
public enum Type {
/** comparable type indicating this RowId should always compare less than
normal RowIds */
ALWAYS_FIRST,
/** comparable type indicating this RowId should always compare
normally */
NORMAL,
/** comparable type indicating this RowId should always compare greater
than normal RowIds */
ALWAYS_LAST;
}
/** special rowId which will sort before any other valid rowId */
public static final RowId FIRST_ROW_ID = new RowId(
FIRST_PAGE_NUMBER, INVALID_ROW_NUMBER);
/** special rowId which will sort after any other valid rowId */
public static final RowId LAST_ROW_ID = new RowId(
LAST_PAGE_NUMBER, INVALID_ROW_NUMBER);
private final int _pageNumber;
private final int _rowNumber;
private final Type _type;
/**
* Creates a new <code>RowId</code> instance.
*
*/
public RowId(int pageNumber,int rowNumber) {
_pageNumber = pageNumber;
_rowNumber = rowNumber;
_type = ((_pageNumber == FIRST_PAGE_NUMBER) ? Type.ALWAYS_FIRST :
((_pageNumber == LAST_PAGE_NUMBER) ? Type.ALWAYS_LAST :
Type.NORMAL));
}
public int getPageNumber() {
return _pageNumber;
}
public int getRowNumber() {
return _rowNumber;
}
/**
* Returns {@code true} if this rowId potentially represents an actual row
* of data, {@code false} otherwise.
*/
public boolean isValid() {
return((getRowNumber() >= 0) && (getPageNumber() >= 0));
}
public Type getType() {
return _type;
}
public int compareTo(RowId other) {
return new CompareToBuilder()
.append(getType(), other.getType())
.append(getPageNumber(), other.getPageNumber())
.append(getRowNumber(), other.getRowNumber())
.toComparison();
}
@Override
public int hashCode() {
return getPageNumber() ^ getRowNumber();
}
@Override
public boolean equals(Object o) {
return ((this == o) ||
((o != null) && (getClass() == o.getClass()) &&
(getPageNumber() == ((RowId)o).getPageNumber()) &&
(getRowNumber() == ((RowId)o).getRowNumber())));
}
@Override
public String toString() {
return getPageNumber() + ":" + getRowNumber();
}
}
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