    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.dbutils.wrappers;
    018
    019import java.lang.reflect.InvocationHandler;
    020import java.lang.reflect.Method;
    021import java.sql.ResultSet;
    022
    023import org.apache.commons.dbutils.ProxyFactory;
    024
    025/**
    026 * Wraps a {@code ResultSet} to trim strings returned by the
    027 * {@code getString()} and {@code getObject()} methods.
    028 *
    029 * <p>
    030 * Usage Example:
    031 * This example shows how to decorate ResultSets so processing continues as
    032 * normal but all Strings are trimmed before being returned from the
    033 * {@code ResultSet}.
    034 * </p>
    035 *
    036 * <pre>
    037 * ResultSet resultSet = // somehow get a ResultSet;
    038 *
    039 * // Substitute wrapped ResultSet with additional behavior for real ResultSet
    040 * resultSet = StringTrimmedResultSet.wrap(resultSet);
    041 *
    042 * // Pass wrapped ResultSet to processor
    043 * List list = new BasicRowProcessor().toBeanList(resultSet);
    044 * </pre>
    045 */
    046public class StringTrimmedResultSet implements InvocationHandler {
    047
    048    /**
    049     * Wraps the {@code ResultSet} in an instance of this class.  This is
    050     * equivalent to:
    051     * <pre>
    052     * ProxyFactory.instance().createResultSet(new StringTrimmedResultSet(resultSet));
    053     * </pre>
    054     *
    055     * @param resultSet The {@code ResultSet} to wrap.
    056     * @return wrapped ResultSet
    057     */
    058    public static ResultSet wrap(final ResultSet resultSet) {
    059        return ProxyFactory.instance().createResultSet(new StringTrimmedResultSet(resultSet));
    060    }
    061
    062    /**
    063     * The wrapped result.
    064     */
    065    private final ResultSet resultSet;
    066
    067    /**
    068     * Constructs a new instance of {@code StringTrimmedResultSet}
    069     * to wrap the specified {@code ResultSet}.
    070     * @param resultSet ResultSet to wrap
    071     */
    072    public StringTrimmedResultSet(final ResultSet resultSet) {
    073        this.resultSet = resultSet;
    074    }
    075
    076    /**
    077     * Intercept calls to the {@code getString()} and
    078     * {@code getObject()} methods and trim any Strings before they're
    079     * returned.
    080     *
    081     * @see java.lang.reflect.InvocationHandler#invoke(Object, java.lang.reflect.Method, Object[])
    082     * @param proxy Not used; all method calls go to the internal result set
    083     * @param method The method to invoke on the result set
    084     * @param args The arguments to pass to the result set
    085     * @return string trimmed result
    086     * @throws Throwable error
    087     */
    088    @Override
    089    public Object invoke(final Object proxy, final Method method, final Object[] args)
    090        throws Throwable {
    091
    092        Object result = method.invoke(this.resultSet, args);
    093
    094        if (result instanceof String
    095                && (method.getName().equals("getObject")
    096                || method.getName().equals("getString"))) {
    097            result = ((String) result).trim();
    098        }
    099
    100        return result;
    101    }
    102
    103}