org.h2.index.Cursor Maven / Gradle / Ivy
/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.index;
import org.h2.result.Row;
import org.h2.result.SearchRow;
/**
* A cursor is a helper object to iterate through an index.
* For indexes are sorted (such as the b tree index), it can iterate
* to the very end of the index. For other indexes that don't support
* that (such as a hash index), only one row is returned.
* The cursor is initially positioned before the first row, that means
* next() must be called before accessing data.
*
*/
public interface Cursor {
/**
* Get the complete current row.
* All column are available.
*
* @return the complete row
*/
Row get();
/**
* Get the current row.
* Only the data for indexed columns is available in this row.
*
* @return the search row
*/
SearchRow getSearchRow();
/**
* Skip to the next row if one is available.
*
* @return true if another row is available
*/
boolean next();
/**
* Skip to the previous row if one is available.
* No filtering is made here.
*
* @return true if another row is available
*/
boolean previous();
}