/* | |
* Licensed to the Apache Software Foundation (ASF) under one or more | |
* contributor license agreements. See the NOTICE file distributed with | |
* this work for additional information 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 with | |
* the License. You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
package org.apache.commons.dbutils.handlers; | |
import java.sql.ResultSet; | |
import java.sql.SQLException; | |
/** | |
* {@code ResultSetHandler} implementation that converts one | |
* {@code ResultSet} column into a {@code List} of | |
* {@code Object}s. This class is thread safe. | |
* | |
* @param <T> The type of the column. | |
* @see org.apache.commons.dbutils.ResultSetHandler | |
* @since 1.1 | |
*/ | |
public class ColumnListHandler<T> extends AbstractListHandler<T> { | |
/** | |
* The column number to retrieve. | |
*/ | |
private final int columnIndex; | |
/** | |
* The column name to retrieve. Either columnName or columnIndex | |
* will be used but never both. | |
*/ | |
private final String columnName; | |
/** | |
* Creates a new instance of ColumnListHandler. The first column of each | |
* row will be returned from {@code handle()}. | |
*/ | |
public ColumnListHandler() { | |
this(1, null); | |
} | |
/** | |
* Creates a new instance of ColumnListHandler. | |
* | |
* @param columnIndex The index of the column to retrieve from the | |
* {@code ResultSet}. | |
*/ | |
public ColumnListHandler(final int columnIndex) { | |
this(columnIndex, null); | |
} | |
/** Private Helper | |
* @param columnIndex The index of the column to retrieve from the | |
* {@code ResultSet}. | |
* @param columnName The name of the column to retrieve from the | |
* {@code ResultSet}. | |
*/ | |
private ColumnListHandler(final int columnIndex, final String columnName) { | |
this.columnIndex = columnIndex; | |
this.columnName = columnName; | |
} | |
/** | |
* Creates a new instance of ColumnListHandler. | |
* | |
* @param columnName The name of the column to retrieve from the | |
* {@code ResultSet}. | |
*/ | |
public ColumnListHandler(final String columnName) { | |
this(1, columnName); | |
} | |
/** | |
* Returns one {@code ResultSet} column value as {@code Object}. | |
* @param resultSet {@code ResultSet} to process. | |
* @return {@code Object}, never {@code null}. | |
* | |
* @throws SQLException if a database access error occurs | |
* @throws ClassCastException if the class datatype does not match the column type | |
* | |
* @see org.apache.commons.dbutils.handlers.AbstractListHandler#handle(ResultSet) | |
*/ | |
// We assume that the user has picked the correct type to match the column | |
// so getObject will return the appropriate type and the cast will succeed. | |
@SuppressWarnings("unchecked") | |
@Override | |
protected T handleRow(final ResultSet resultSet) throws SQLException { | |
if (this.columnName == null) { | |
return (T) resultSet.getObject(this.columnIndex); | |
} | |
return (T) resultSet.getObject(this.columnName); | |
} | |
} |