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 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *    http://www.apache.org/licenses/LICENSE-2.0
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 *  KIND, either express or implied.  See the License for the
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package org.apache.cayenne.dba.mysql;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.apache.cayenne.access.OperationObserver;
import org.apache.cayenne.access.QueryLogger;
import org.apache.cayenne.access.jdbc.ProcedureAction;
import org.apache.cayenne.access.jdbc.RowDescriptor;
import org.apache.cayenne.access.trans.ProcedureTranslator;
import org.apache.cayenne.dba.DbAdapter;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.query.ProcedureQuery;

/**
 * @since 3.0
 * @author Andrus Adamchik
 */
class MySQLProcedureAction extends ProcedureAction {

    public MySQLProcedureAction(ProcedureQuery query, DbAdapter adapter,
            EntityResolver entityResolver) {
        super(query, adapter, entityResolver);
    }

    public void performAction(Connection connection, OperationObserver observer)
            throws SQLException, Exception {

        processedResultSets = 0;

        ProcedureTranslator transl = createTranslator(connection);
        CallableStatement statement = (CallableStatement) transl.createStatement();

        try {

            // this is one difference with super - we need to read the first result set
            // without calling 'getMoreResults' - which may actually be a good default
            // strategy?
            boolean firstResult = statement.execute();

            // read out parameters
            readProcedureOutParameters(statement, observer);

            // read first result
            if (firstResult) {
                processResultSet(statement, observer);
            }
            else if (!processUpdate(statement, observer)) {
                return;
            }

            // read the rest of the query
            while (true) {
                if (statement.getMoreResults()) {
                    processResultSet(statement, observer);
                }
                else if (!processUpdate(statement, observer)) {
                    break;
                }
            }
        }
        finally {
            try {
                statement.close();
            }
            catch (SQLException ex) {

            }
        }
    }

    private void processResultSet(CallableStatement statement, OperationObserver observer)
            throws Exception {
        ResultSet rs = statement.getResultSet();

        try {
            RowDescriptor descriptor = describeResultSet(rs, processedResultSets++);
            readResultSet(rs, descriptor, query, observer);
        }
        finally {
            try {
                rs.close();
            }
            catch (SQLException ex) {
            }
        }
    }

    private boolean processUpdate(CallableStatement statement, OperationObserver observer)
            throws Exception {
        int updateCount = statement.getUpdateCount();
        if (updateCount == -1) {
            return false;
        }
        QueryLogger.logUpdateCount(updateCount);
        observer.nextCount(query, updateCount);

        return true;
    }

    /**
     * Creates a translator that adds parenthesis to no-param queries.
     */
    // see CAY-750 for the problem description
    protected ProcedureTranslator createTranslator(Connection connection) {
        ProcedureTranslator translator = new MySQLProcedureTranslator();
        translator.setAdapter(getAdapter());
        translator.setQuery(query);
        translator.setEntityResolver(getEntityResolver());
        translator.setConnection(connection);
        return translator;
    }

    // same as postgres translator - should we make this the default?
    static class MySQLProcedureTranslator extends ProcedureTranslator {

        protected String createSqlString() {

            String sql = super.createSqlString();

            // add empty parameter parenthesis
            if (sql.endsWith("}") && !sql.endsWith(")}")) {
                sql = sql.substring(0, sql.length() - 1) + "()}";
            }

            return sql;
        }
    }
}
