Package org.apache.commons.math4.util

Class IntegerSequence.Incrementor

java.lang.Object
org.apache.commons.math4.util.IntegerSequence.Incrementor
All Implemented Interfaces:
java.util.Iterator<java.lang.Integer>
Enclosing class:
IntegerSequence
public static class IntegerSequence.Incrementor
extends java.lang.Object
implements java.util.Iterator<java.lang.Integer>
Utility that increments a counter until a maximum is reached, at which point, the instance will by default throw a MaxCountExceededException. However, the user is able to override this behaviour by defining a custom callback, in order to e.g. select which exception must be thrown.

  • Method Details

    • create

      public static IntegerSequence.Incrementor create()
      Factory method that creates a default instance. The initial and maximal values are set to 0. For the new instance to be useful, the maximal count must be set by calling withMaximalCount.
      Returns:
      an new instance.

    • withStart

      public IntegerSequence.Incrementor withStart​(int start)
      Creates a new instance with a given initial value. The counter is reset to the initial value.
      Parameters:
      start - Initial value of the counter.
      Returns:
      a new instance.

    • withMaximalCount

      public IntegerSequence.Incrementor withMaximalCount​(int max)
      Creates a new instance with a given maximal count. The counter is reset to the initial value.
      Parameters:
      max - Maximal count.
      Returns:
      a new instance.

    • withIncrement

      public IntegerSequence.Incrementor withIncrement​(int step)
      Creates a new instance with a given increment. The counter is reset to the initial value.
      Parameters:
      step - Increment.
      Returns:
      a new instance.

    • withCallback

      public IntegerSequence.Incrementor withCallback​(IntegerSequence.Incrementor.MaxCountExceededCallback cb)
      Creates a new instance with a given callback. The counter is reset to the initial value.
      Parameters:
      cb - Callback to be called at counter exhaustion.
      Returns:
      a new instance.

    • getMaximalCount

      public int getMaximalCount()
      Gets the upper limit of the counter.
      Returns:
      the counter upper limit.

    • getCount

      public int getCount()
      Gets the current count.
      Returns:
      the current count.

    • canIncrement

      public boolean canIncrement()
      Checks whether incrementing the counter nTimes is allowed.
      Returns:
      false if calling increment() will trigger a MaxCountExceededException, true otherwise.

    • canIncrement

      public boolean canIncrement​(int nTimes)
      Checks whether incrementing the counter several times is allowed.
      Parameters:
      nTimes - Number of increments.
      Returns:
      false if calling increment(nTimes) would call the callback true otherwise.

    • increment

      public void increment​(int nTimes) throws MaxCountExceededException
      Performs multiple increments.
      Parameters:
      nTimes - Number of increments.
      Throws:
      MaxCountExceededException - at counter exhaustion.
      NotStrictlyPositiveException - if nTimes <= 0.
      See Also:
      increment()

    • increment

      public void increment() throws MaxCountExceededException
      Adds the increment value to the current iteration count. At counter exhaustion, this method will call the trigger method of the callback object passed to the withCallback(MaxCountExceededCallback) method. If not explictly set, a default callback is used that will throw a MaxCountExceededException.
      Throws:
      MaxCountExceededException - at counter exhaustion, unless a custom callback has been set.
      See Also:
      increment(int)

    • hasNext

      public boolean hasNext()
      Specified by:
      hasNext in interface java.util.Iterator<java.lang.Integer>

    • next

      public java.lang.Integer next()
      Specified by:
      next in interface java.util.Iterator<java.lang.Integer>

    • remove

      public void remove()
      Not applicable.
      Specified by:
      remove in interface java.util.Iterator<java.lang.Integer>
      Throws:
      MathUnsupportedOperationException - always