StringUtils.java

package org.apache.samoa.moa.core;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * Licensed 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.
 * #L%
 */

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();
  }
}