LatchingValue.java

package indrora.atomic.utils;

/**
 * LatchingValue: A simple trippable value.
 * <p/>
 * Latching Values have 2 states: Default and Latched. Whenever the "current" value is read,
 * the state becomes "latched", thus changing the value.
 * <p/>
 * Latched values however can be "un-tripped" (reset) to their default value, in case something does need
 * to reset this "trap"
 *
 * @param <E>
 * @author indrora
 */
public class LatchingValue<E> {
  E currentValue;
  final E defaultValue;
  final E latchedValue;

  /**
   * Default constructor.
   *
   * @param defaultValue Default value of the latch
   * @param latchedValue Tripped value of the latch
   */
  public LatchingValue(E defaultValue, E latchedValue) {
    this.defaultValue = defaultValue;
    this.currentValue = this.defaultValue;
    this.latchedValue = latchedValue;
  }

  /**
   * Resets the latch state.
   */
  public void reset() {
    this.currentValue = this.defaultValue;
  }

  /**
   * Gets the current value of the latch.
   * <p/>
   * This will trip the latch.
   *
   * @return The value of the latch.
   */
  public E getValue() {
    E tmp = this.currentValue;
    this.currentValue = this.latchedValue;
    return tmp;
  }
}