com.cloudera.sqoop.util.ResultSetPrinter.java Source code

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Here is the source code for com.cloudera.sqoop.util.ResultSetPrinter.java

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/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. 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 com.cloudera.sqoop.util;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.util.StringUtils;

/**
 * Utility methods to format and print ResultSet objects.
 */
public class ResultSetPrinter {

    public static final Log LOG = LogFactory.getLog(ResultSetPrinter.class.getName());

    // max output width to allocate to any column of the printed results.
    private static final int MAX_COL_WIDTH = 20;

    /**
     * Print 'str' to the string builder, padded to 'width' chars.
     */
    private static void printPadded(StringBuilder sb, String str, int width) {
        int numPad;
        if (null == str) {
            sb.append("(null)");
            numPad = width - "(null)".length();
        } else {
            sb.append(str);
            numPad = width - str.length();
        }

        for (int i = 0; i < numPad; i++) {
            sb.append(' ');
        }
    }

    private static final String COL_SEPARATOR = " | ";
    private static final String LEFT_BORDER = "| ";

    /**
     * Format the contents of the ResultSet into something that could be printed
     * neatly; the results are appended to the supplied StringBuilder.
     */
    public final void printResultSet(PrintWriter pw, ResultSet results) throws IOException {
        try {
            StringBuilder sbNames = new StringBuilder();
            int cols = results.getMetaData().getColumnCount();

            int[] colWidths = new int[cols];
            ResultSetMetaData metadata = results.getMetaData();
            sbNames.append(LEFT_BORDER);
            for (int i = 1; i < cols + 1; i++) {
                String colName = metadata.getColumnName(i);
                colWidths[i - 1] = Math.min(metadata.getColumnDisplaySize(i), MAX_COL_WIDTH);
                if (colName == null || colName.equals("")) {
                    colName = metadata.getColumnLabel(i) + "*";
                }
                printPadded(sbNames, colName, colWidths[i - 1]);
                sbNames.append(COL_SEPARATOR);
            }
            sbNames.append('\n');

            StringBuilder sbPad = new StringBuilder();
            for (int i = 0; i < cols; i++) {
                for (int j = 0; j < COL_SEPARATOR.length() + colWidths[i]; j++) {
                    sbPad.append('-');
                }
            }
            sbPad.append('-');
            sbPad.append('\n');

            pw.print(sbPad.toString());
            pw.print(sbNames.toString());
            pw.print(sbPad.toString());

            while (results.next()) {
                StringBuilder sb = new StringBuilder();
                sb.append(LEFT_BORDER);
                for (int i = 1; i < cols + 1; i++) {
                    printPadded(sb, results.getString(i), colWidths[i - 1]);
                    sb.append(COL_SEPARATOR);
                }
                sb.append('\n');
                pw.print(sb.toString());
            }

            pw.print(sbPad.toString());
        } catch (SQLException sqlException) {
            LOG.error("Error reading from database: " + StringUtils.stringifyException(sqlException));
        }
    }

}