Application: gvSIG desktop

package org.gvsig.fmap.dal.store.jdbc2.spi.operations;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import org.apache.commons.lang3.StringUtils;

import org.gvsig.fmap.dal.exception.DataException;

import org.gvsig.fmap.dal.store.jdbc2.JDBCHelper;

import org.gvsig.fmap.dal.store.jdbc2.spi.JDBCSQLBuilderBase;

import org.gvsig.fmap.dal.store.jdbc.exception.JDBCSQLException;

import org.gvsig.fmap.dal.store.jdbc2.JDBCUtils;

public class TableIsEmptyOperation extends AbstractConnectionOperation {

    private final String schemaName;

    private final String tableName;

    private final String subquery;

    private final String baseFilter;

    private final String filter;

    private final String dbName;

    public TableIsEmptyOperation(

            JDBCHelper helper

        ) {

        this(helper, null, null, null, null, null, null);

    }

    public TableIsEmptyOperation(

            JDBCHelper helper,

            String dbName,

            String schemaName,

            String tableName,

            String subquery,

            String baseFilter,

            String filter

        ) {

        super(helper);

        this.dbName = dbName;

        this.schemaName = schemaName;

        this.tableName = tableName;

        this.subquery = subquery;

        this.baseFilter = baseFilter;

        this.filter = filter;

    }

    @Override

    public final Object perform(Connection conn) throws DataException {

        return this.tableIsEmpty(conn,

                dbName, schemaName, tableName, subquery, baseFilter, filter);

    }

    public boolean tableIsEmpty(Connection conn,

            String database,

            String schema,

            String table,

            String subquery,

            String baseFilter,

            String filter) throws DataException {

        JDBCSQLBuilderBase sqlbuilder = this.createSQLBuilder();

        sqlbuilder.select().column().all();

        sqlbuilder.select().from().table().database(database).schema(schema).name(table);

        sqlbuilder.select().from().subquery(subquery);

        if (!StringUtils.isEmpty(baseFilter)) {

            sqlbuilder.select().where().set( sqlbuilder.custom(baseFilter) );

        }

        if (!StringUtils.isEmpty(filter)) {

            // El and() hace un set() si no hay un filtro previo

            sqlbuilder.select().where().and(sqlbuilder.custom(filter));

        }

        sqlbuilder.select().limit(1);

        String sql = sqlbuilder.select().toString();

        Statement st = null;

        ResultSet rs = null;

        try {

            st = conn.createStatement();

            rs = JDBCUtils.executeQuery(st, sql);

            return !rs.next();

        } catch (SQLException ex) {

            throw new JDBCSQLException(ex);

        } finally {

            JDBCUtils.closeQuietly(st);

            JDBCUtils.closeQuietly(rs);

        }

    }

}