com.insidecoding.updatr.model.Version Maven / Gradle / Ivy

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package com.insidecoding.updatr.model;

/**
 * Abstracts the representation of a (software) version in format X.X.X.X...
 * 
 * @author ludovicianul
 * 
 */
public final class Version implements Comparable {

  private Integer[] items;

  private Version(String[] itms) {
    if (itms == null) {
      throw new IllegalArgumentException("must provide non-null items array");
    }

    if (itms.length == 0) {
      throw new IllegalArgumentException("At least one component required");
    }

    this.items = new Integer[itms.length];

    for (int i = 0; i < itms.length; i++) {
      this.items[i] = Integer.valueOf(itms[i]);
      if (this.items[i] < 0) {
        throw new IllegalArgumentException("must only use positive numbers; offending value "
            + itms[i]);
      }
    }

  }

  /**
   * It creates a version object from a given String representation.
   * 
   * @param versionSpec
   *          version in format X.X.X.
   * @return a Version representation of the given String.
   */
  public static Version fromString(String versionSpec) {

    return new Version(parse(versionSpec));
  }

  @Override
  public int compareTo(Version otheVersion) {

    if (this == otheVersion) {
      return 0;
    }
    int result = 0;
    int length = Math.min(items.length, otheVersion.items.length);
    int idx = 0;

    while (result == 0 && idx < length) {
      int current = items[idx].compareTo(otheVersion.items[idx]);

      if (current != 0) {
        result = current;
      }

      idx++;
    }

    if (result == 0) {
      if (idx < items.length) {
        result = items[idx];
      } else if (idx < otheVersion.items.length) {
        result = -otheVersion.items[idx];
      }
    }

    return result;
  }

  private static String[] parse(String versionStr) {
    if (versionStr == null) {
      return null;
    }

    final String[] items = versionStr.replaceAll("[^\\d.]", "").split("\\.");

    for (int i = 0; i < items.length; i++) {
      items[i] = items[i].trim();
    }

    return items;
  }

  @Override
  public String toString() {
    StringBuilder builder = new StringBuilder(items[0].toString());

    if (items.length >= 1) {
      for (int i = 1; i < items.length; i++) {
        builder.append('.').append(items[i]);
      }
    }
    return builder.toString();
  }

}