/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.dialect.pagination;

import java.util.Locale;

import org.hibernate.engine.spi.RowSelection;


Author:Brett Meyer
/** * @author Brett Meyer */
public class TopLimitHandler extends AbstractLimitHandler { private final boolean supportsVariableLimit; private final boolean bindLimitParametersFirst; public TopLimitHandler(boolean supportsVariableLimit, boolean bindLimitParametersFirst) { this.supportsVariableLimit = supportsVariableLimit; this.bindLimitParametersFirst = bindLimitParametersFirst; } @Override public boolean supportsLimit() { return true; } @Override public boolean useMaxForLimit() { return true; } @Override public boolean supportsLimitOffset() { return supportsVariableLimit; } @Override public boolean supportsVariableLimit() { return supportsVariableLimit; } @Override public boolean bindLimitParametersFirst() { return bindLimitParametersFirst; } @Override public String processSql(String sql, RowSelection selection) { if (LimitHelper.hasFirstRow( selection )) { throw new UnsupportedOperationException( "query result offset is not supported" ); } final int selectIndex = sql.toLowerCase(Locale.ROOT).indexOf( "select" ); final int selectDistinctIndex = sql.toLowerCase(Locale.ROOT).indexOf( "select distinct" ); final int insertionPoint = selectIndex + (selectDistinctIndex == selectIndex ? 15 : 6); StringBuilder sb = new StringBuilder( sql.length() + 8 ) .append( sql ); if ( supportsVariableLimit ) { sb.insert( insertionPoint, " TOP ? " ); } else { sb.insert( insertionPoint, " TOP " + getMaxOrLimit( selection ) + " " ); } return sb.toString(); } }