StringUtils.java Source code

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Here is the source code for StringUtils.java

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/**
 * 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.
 */

import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.InetAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.text.DateFormat;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.StringTokenizer;
import java.util.Collection;

/**
 * General string utils
 */
public class StringUtils {

    final public static char COMMA = ',';
    final public static String COMMA_STR = ",";
    final public static char ESCAPE_CHAR = '\\';
    private static DecimalFormat oneDecimal = new DecimalFormat("0.0");

    /**
     * Format a percentage for presentation to the user.
     * @param done the percentage to format (0.0 to 1.0)
     * @param digits the number of digits past the decimal point
     * @return a string representation of the percentage
     */
    public static String formatPercent(double done, int digits) {
        DecimalFormat percentFormat = new DecimalFormat("0.00%");
        double scale = Math.pow(10.0, digits + 2);
        double rounded = Math.floor(done * scale);
        percentFormat.setDecimalSeparatorAlwaysShown(false);
        percentFormat.setMinimumFractionDigits(digits);
        percentFormat.setMaximumFractionDigits(digits);
        return percentFormat.format(rounded / scale);
    }
}