SpinnerNumberModelpublic class SpinnerNumberModel extends AbstractSpinnerModel implements SerializableA SpinnerModel for sequences of numbers.
The upper and lower bounds of the sequence are defined
by properties called minimum and
maximum. The size of the increase or decrease
computed by the nextValue and
previousValue methods is defined by a property called
stepSize. The minimum and
maximum properties can be null
to indicate that the sequence has no lower or upper limit.
All of the properties in this class are defined in terms of two
generic types: Number and
Comparable, so that all Java numeric types
may be accommodated. Internally, there's only support for
values whose type is one of the primitive Number types:
Double, Float, Long,
Integer, Short, or Byte.
To create a SpinnerNumberModel for the integer
range zero to one hundred, with
fifty as the initial value, one could write:
Integer value = new Integer(50);
Integer min = new Integer(0);
Integer max = new Integer(100);
Integer step = new Integer(1);
SpinnerNumberModel model = new SpinnerNumberModel(value, min, max, step);
int fifty = model.getNumber().intValue();
Spinners for integers and doubles are common, so special constructors
for these cases are provided. For example to create the model in
the previous example, one could also write:
SpinnerNumberModel model = new SpinnerNumberModel(50, 0, 100, 1);
This model inherits a ChangeListener.
The ChangeListeners are notified
whenever the model's value, stepSize,
minimum, or maximum properties changes. |
| Fields Summary |
|---|
| private Number | stepSize | | private Number | value | | private Comparable | minimum | | private Comparable | maximum |
| Constructors Summary |
|---|
public SpinnerNumberModel(Number value, Comparable minimum, Comparable maximum, Number stepSize)Constructs a SpinnerModel that represents
a closed sequence of
numbers from minimum to maximum. The
nextValue and previousValue methods
compute elements of the sequence by adding or subtracting
stepSize respectively. All of the parameters
must be mutually Comparable, value
and stepSize must be instances of Integer
Long, Float, or Double.
The minimum and maximum parameters
can be null to indicate that the range doesn't
have an upper or lower bound.
If value or stepSize is null,
or if both minimum and maximum
are specified and mininum > maximum then an
IllegalArgumentException is thrown.
Similarly if (minimum <= value <= maximum) is false,
an IllegalArgumentException is thrown.
if ((value == null) || (stepSize == null)) {
throw new IllegalArgumentException("value and stepSize must be non-null");
}
if (!(((minimum == null) || (minimum.compareTo(value) <= 0)) &&
((maximum == null) || (maximum.compareTo(value) >= 0)))) {
throw new IllegalArgumentException("(minimum <= value <= maximum) is false");
}
this.value = value;
this.minimum = minimum;
this.maximum = maximum;
this.stepSize = stepSize;
| public SpinnerNumberModel(int value, int minimum, int maximum, int stepSize)Constructs a SpinnerNumberModel with the specified
value, minimum/maximum bounds,
and stepSize.
this(new Integer(value), new Integer(minimum), new Integer(maximum), new Integer(stepSize));
| public SpinnerNumberModel(double value, double minimum, double maximum, double stepSize)Constructs a SpinnerNumberModel with the specified
value, minimum/maximum bounds,
and stepSize.
this(new Double(value), new Double(minimum), new Double(maximum), new Double(stepSize));
| public SpinnerNumberModel()Constructs a SpinnerNumberModel with no
minimum or maximum value,
stepSize equal to one, and an initial value of zero.
this(new Integer(0), null, null, new Integer(1));
|
| Methods Summary |
|---|
| public java.lang.Comparable | getMaximum()Returns the last number in the sequence.
return maximum;
| | public java.lang.Comparable | getMinimum()Returns the first number in this sequence.
return minimum;
| | public java.lang.Object | getNextValue()Returns the next number in the sequence.
return incrValue(+1);
| | public java.lang.Number | getNumber()Returns the value of the current element of the sequence.
return value;
| | public java.lang.Object | getPreviousValue()Returns the previous number in the sequence.
return incrValue(-1);
| | public java.lang.Number | getStepSize()Returns the size of the value change computed by the
getNextValue
and getPreviousValue methods.
return stepSize;
| | public java.lang.Object | getValue()Returns the value of the current element of the sequence.
return value;
| | private java.lang.Number | incrValue(int dir)
Number newValue;
if ((value instanceof Float) || (value instanceof Double)) {
double v = value.doubleValue() + (stepSize.doubleValue() * (double)dir);
if (value instanceof Double) {
newValue = new Double(v);
}
else {
newValue = new Float(v);
}
}
else {
long v = value.longValue() + (stepSize.longValue() * (long)dir);
if (value instanceof Long) {
newValue = new Long(v);
}
else if (value instanceof Integer) {
newValue = new Integer((int)v);
}
else if (value instanceof Short) {
newValue = new Short((short)v);
}
else {
newValue = new Byte((byte)v);
}
}
if ((maximum != null) && (maximum.compareTo(newValue) < 0)) {
return null;
}
if ((minimum != null) && (minimum.compareTo(newValue) > 0)) {
return null;
}
else {
return newValue;
}
| | public void | setMaximum(java.lang.Comparable maximum)Changes the upper bound for numbers in this sequence.
If maximum is null, then there
is no upper bound. No bounds checking is done here; the new
maximum value may invalidate the
(minimum <= value < maximum)
invariant enforced by the constructors. This is to simplify updating
the model, naturally one should ensure that the invariant is true
before calling the next, previous,
or setValue methods.
Typically this property is a Number of the same type
as the value however it's possible to use any
Comparable with a compareTo
method for a Number with the same type as the value.
See
setMinimum for an example.
This method fires a ChangeEvent if the
maximum has changed.
if ((maximum == null) ? (this.maximum != null) : !maximum.equals(this.maximum)) {
this.maximum = maximum;
fireStateChanged();
}
| | public void | setMinimum(java.lang.Comparable minimum)Changes the lower bound for numbers in this sequence.
If minimum is null,
then there is no lower bound. No bounds checking is done here;
the new minimum value may invalidate the
(minimum <= value <= maximum)
invariant enforced by the constructors. This is to simplify updating
the model, naturally one should ensure that the invariant is true
before calling the getNextValue,
getPreviousValue, or setValue methods.
Typically this property is a Number of the same type
as the value however it's possible to use any
Comparable with a compareTo
method for a Number with the same type as the value.
For example if value was a Long,
minimum might be a Date subclass defined like this:
MyDate extends Date { // Date already implements Comparable
public int compareTo(Long o) {
long t = getTime();
return (t < o.longValue() ? -1 : (t == o.longValue() ? 0 : 1));
}
}
This method fires a ChangeEvent
if the minimum has changed.
if ((minimum == null) ? (this.minimum != null) : !minimum.equals(this.minimum)) {
this.minimum = minimum;
fireStateChanged();
}
| | public void | setStepSize(java.lang.Number stepSize)Changes the size of the value change computed by the
getNextValue and getPreviousValue
methods. An IllegalArgumentException
is thrown if stepSize is null.
This method fires a ChangeEvent if the
stepSize has changed.
if (stepSize == null) {
throw new IllegalArgumentException("null stepSize");
}
if (!stepSize.equals(this.stepSize)) {
this.stepSize = stepSize;
fireStateChanged();
}
| | public void | setValue(java.lang.Object value)Sets the current value for this sequence. If value is
null, or not a Number, an
IllegalArgumentException is thrown. No
bounds checking is done here; the new value may invalidate the
(minimum <= value <= maximum)
invariant enforced by the constructors. It's also possible to set
the value to be something that wouldn't naturally occur in the sequence,
i.e. a value that's not modulo the stepSize.
This is to simplify updating the model, and to accommodate
spinners that don't want to restrict values that have been
directly entered by the user. Naturally, one should ensure that the
(minimum <= value <= maximum) invariant is true
before calling the next, previous, or
setValue methods.
This method fires a ChangeEvent if the value has changed.
if ((value == null) || !(value instanceof Number)) {
throw new IllegalArgumentException("illegal value");
}
if (!value.equals(this.value)) {
this.value = (Number)value;
fireStateChanged();
}
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