org.apache.commons.math3.util

Class IntegerSequence.Incrementor

java.lang.Object

org.apache.commons.math3.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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	IntegerSequence.Incrementor.MaxCountExceededCallback Defines a method to be called at counter exhaustion.

Field Summary

Fields

Modifier and Type	Field and Description
private static IntegerSequence.Incrementor.MaxCountExceededCallback	CALLBACK Default callback.
private int	count Current count.
private int	increment Increment.
private int	init Initial value the counter.
private IntegerSequence.Incrementor.MaxCountExceededCallback	maxCountCallback Function called at counter exhaustion.
private int	maximalCount Upper limit for the counter.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	IntegerSequence.Incrementor(int start, int max, int step, IntegerSequence.Incrementor.MaxCountExceededCallback cb) Creates an incrementor.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canIncrement() Checks whether incrementing the counter nTimes is allowed.
boolean	canIncrement(int nTimes) Checks whether incrementing the counter several times is allowed.
static IntegerSequence.Incrementor	create() Factory method that creates a default instance.
int	getCount() Gets the current count.
int	getMaximalCount() Gets the upper limit of the counter.
boolean	hasNext()
void	increment() Adds the increment value to the current iteration count.
void	increment(int nTimes) Performs multiple increments.
java.lang.Integer	next()
void	remove() Not applicable.
IntegerSequence.Incrementor	withCallback(IntegerSequence.Incrementor.MaxCountExceededCallback cb) Creates a new instance with a given callback.
IntegerSequence.Incrementor	withIncrement(int step) Creates a new instance with a given increment.
IntegerSequence.Incrementor	withMaximalCount(int max) Creates a new instance with a given maximal count.
IntegerSequence.Incrementor	withStart(int start) Creates a new instance with a given initial value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CALLBACK

private static final IntegerSequence.Incrementor.MaxCountExceededCallback CALLBACK

Default callback.

init

private final int init

Initial value the counter.

maximalCount

private final int maximalCount

Upper limit for the counter.

increment

private final int increment

Increment.

maxCountCallback

private final IntegerSequence.Incrementor.MaxCountExceededCallback maxCountCallback

Function called at counter exhaustion.

count

private int count

Current count.

Constructor Detail

IntegerSequence.Incrementor

private IntegerSequence.Incrementor(int start,
                           int max,
                           int step,
                           IntegerSequence.Incrementor.MaxCountExceededCallback cb)
                             throws NullArgumentException

Creates an incrementor. The counter will be exhausted either when max is reached or when nTimes increments have been performed.

Parameters:

start - Initial value.

max - Maximal count.

step - Increment.

cb - Function to be called when the maximal count has been reached.

Throws:

NullArgumentException - if cb is null.

Method Detail

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 explicitly 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