org.eobjects.metamodel.jdbc.dialects.PostgresqlQueryRewriter Maven / Gradle / Ivy

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/**
 * eobjects.org MetaModel
 * Copyright (C) 2010 eobjects.org
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program 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 distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */

package org.eobjects.metamodel.jdbc.dialects;

import org.eobjects.metamodel.jdbc.JdbcDataContext;
import org.eobjects.metamodel.query.FromItem;
import org.eobjects.metamodel.query.Query;
import org.eobjects.metamodel.schema.Schema;
import org.eobjects.metamodel.schema.Table;

public class PostgresqlQueryRewriter extends DefaultQueryRewriter implements
		IQueryRewriter {

	public PostgresqlQueryRewriter(JdbcDataContext dataContext) {
		super(dataContext);
	}

	@Override
	public boolean isFirstRowSupported() {
		return true;
	}

	@Override
	public boolean isMaxRowsSupported() {
		return true;
	}

	/**
	 * If the Max rows and/or First row property of the query is set, then we
	 * will use PostgreSQLs LIMIT and OFFSET functions.
	 */
	@Override
	public String rewriteQuery(Query query) {
		String queryString = super.rewriteQuery(query);
		final Integer maxRows = query.getMaxRows();
		if (maxRows != null) {
			queryString = queryString + " LIMIT " + maxRows;
		}

		final Integer firstRow = query.getFirstRow();
		if (firstRow != null) {
			queryString = queryString + " OFFSET " + firstRow;
		}
		return queryString;
	}

	@Override
	protected String rewriteFromItem(JdbcDataContext strategy, Query query,
			FromItem item) {
		String result = super.rewriteFromItem(strategy, query, item);
		Table table = item.getTable();
		if (table != null) {
			Schema schema = table.getSchema();
			if (schema != null) {
				String schemaName = schema.getName();
				if (schemaName != null) {
					result = result.replaceFirst(schemaName,
							'\"' + schema.getName() + '\"');
				}
			}
		}
		return result;
	}
}