samoa-api/src/main/java/org/apache/samoa/moa/core/StringUtils.java

/*
 * 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.samoa.moa.core;

import java.text.DecimalFormat;

/**
 * Class implementing some string utility methods.
 * 
 * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz)
 * @version $Revision: 7 $
 */
public class StringUtils {

  public static final String newline = System.getProperty("line.separator");

  public static String doubleToString(double value, int fractionDigits) {
    return doubleToString(value, 0, fractionDigits);
  }

  public static String doubleToString(double value, int minFractionDigits,
      int maxFractionDigits) {
    DecimalFormat numberFormat = new DecimalFormat();
    numberFormat.setMinimumFractionDigits(minFractionDigits);
    numberFormat.setMaximumFractionDigits(maxFractionDigits);
    return numberFormat.format(value);
  }

  public static void appendNewline(StringBuilder out) {
    out.append(newline);
  }

  public static void appendIndent(StringBuilder out, int indent) {
    for (int i = 0; i < indent; i++) {
      out.append(' ');
    }
  }

  public static void appendIndented(StringBuilder out, int indent, String s) {
    appendIndent(out, indent);
    out.append(s);
  }

  public static void appendNewlineIndented(StringBuilder out, int indent,
      String s) {
    appendNewline(out);
    appendIndented(out, indent, s);
  }

  public static String secondsToDHMSString(double seconds) {
    if (seconds < 60) {
      return doubleToString(seconds, 2, 2) + 's';
    }
    long secs = (int) (seconds);
    long mins = secs / 60;
    long hours = mins / 60;
    long days = hours / 24;
    secs %= 60;
    mins %= 60;
    hours %= 24;
    StringBuilder result = new StringBuilder();
    if (days > 0) {
      result.append(days);
      result.append('d');
    }
    if ((hours > 0) || (days > 0)) {
      result.append(hours);
      result.append('h');
    }
    if ((hours > 0) || (days > 0) || (mins > 0)) {
      result.append(mins);
      result.append('m');
    }
    result.append(secs);
    result.append('s');
    return result.toString();
  }
}