Examples with ResultIterator org.apache.cayenne.ResultIterator used on opensource projects

Example 6 with ResultIterator

use of org.apache.cayenne.ResultIterator in project cayenne by apache.

the class SelectAction method performAction.

@SuppressWarnings({ "unchecked", "rawtypes", "resource" })
@Override
public void performAction(Connection connection, OperationObserver observer) throws SQLException, Exception {
    final long t1 = System.currentTimeMillis();
    JdbcEventLogger logger = dataNode.getJdbcEventLogger();
    SelectTranslator translator = dataNode.selectTranslator(query);
    final String sql = translator.getSql();
    final DbAttributeBinding[] bindings = translator.getBindings();
    logger.logQuery(sql, bindings);
    PreparedStatement statement = connection.prepareStatement(sql);
    bind(dataNode.getAdapter(), statement, bindings);
    int fetchSize = queryMetadata.getStatementFetchSize();
    if (fetchSize != 0) {
        statement.setFetchSize(fetchSize);
    }
    ResultSet rs;
    // exception happens
    try {
        rs = statement.executeQuery();
    } catch (Exception ex) {
        statement.close();
        throw ex;
    }
    RowDescriptor descriptor = new RowDescriptorBuilder().setColumns(translator.getResultColumns()).getDescriptor(dataNode.getAdapter().getExtendedTypes());
    RowReader<?> rowReader = dataNode.rowReader(descriptor, queryMetadata, translator.getAttributeOverrides());
    ResultIterator it = new JDBCResultIterator(statement, rs, rowReader);
    it = forIteratedResult(it, observer, connection, t1, sql);
    it = forSuppressedDistinct(it, translator);
    it = forFetchLimit(it, translator);
    if (observer.isIteratedResult()) {
        try {
            observer.nextRows(query, it);
        } catch (Exception ex) {
            it.close();
            throw ex;
        }
    } else {
        List<DataRow> resultRows;
        try {
            resultRows = it.allRows();
        } finally {
            it.close();
        }
        dataNode.getJdbcEventLogger().logSelectCount(resultRows.size(), System.currentTimeMillis() - t1, sql);
        observer.nextRows(query, resultRows);
    }
}