com.kohlschutter.util.SystemPropertyUtil Maven / Gradle / Ivy

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package com.kohlschutter.util;

/**
 * Helper methods to simplify working with system properties.
 * 
 * @author Christian Kohlschütter
 */
public final class SystemPropertyUtil {
  private SystemPropertyUtil() {
    throw new IllegalStateException("No instances");
  }

  /**
   * Retrieves an integer value stored as a system property.
   *
   * @param key The name of the system property.
   * @param defaultValue The default value, if no value has been set.
   * @return The value
   * @throws IllegalArgumentException if the default value could not be parsed
   */
  public static int getIntSystemProperty(String key, int defaultValue) {
    String v = System.getProperty(key, null);
    if (v == null || v.trim().isEmpty()) { // NOPMD
      return defaultValue;
    }
    try {
      if ("true".equalsIgnoreCase(v)) {
        return 1;
      } else if ("false".equalsIgnoreCase(v)) {
        return 0;
      }
      return Integer.parseInt(v);
    } catch (Exception e) {
      throw new IllegalArgumentException("Illegal value for system property " + key + ": " + v, e);
    }
  }

  /**
   * Retrieves a boolean value stored as a system property.
   *
   * @param key The name of the system property.
   * @param defaultValue The default value, if no value has been set.
   * @return The value
   * @throws IllegalArgumentException if the default value could not be parsed
   */
  public static boolean getBooleanSystemProperty(String key, boolean defaultValue) {
    String v = System.getProperty(key, null);
    if (v == null || v.trim().isEmpty()) { // NOPMD
      return defaultValue;
    }
    try {
      if ("1".equals(v)) {
        return true;
      } else if ("yes".equalsIgnoreCase(v)) {
        return true;
      } else if ("y".equalsIgnoreCase(v)) {
        return true;
      } else if ("on".equalsIgnoreCase(v)) {
        return true;
      }
      return Boolean.parseBoolean(v);
    } catch (Exception e) {
      throw new IllegalArgumentException("Illegal value for system property " + key + ": " + v, e);
    }
  }
}