net.lucidviews.util
Class VariableNumber

java.lang.Object
  java.lang.Number
      net.lucidviews.util.VariableNumber

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

VariableDouble, VariableLong

public abstract class VariableNumber
extends Number

An abstract base class for Numbers that can change their value.

The mandate of a VariableNumber is to provide a number object that can change value, thereby removing the need to instantiate a new object each time the underlying value is changed.
However, it is important to respect the immutability of an object for encapsulation purposes.
When a software module has created a variable number (using its variable nature to alter its value during some processing algorithm, say) it may want to expose that number externally. At this point the number needs to lose its variability, to prevent other software modules changing its value.
It is for this reason the variable number class provides the functionality to secure the number, closing the object to any further change. Effectively making it read-only.

Since:

1.1

Version:

$Revision: 1.1 $

Author:

Stephen Battey

See Also:

Serialized Form

Field Summary

private boolean

secure Flag set once the value has been fixed, effectively making the number immutable.

Constructor Summary

VariableNumber()

Method Summary

boolean	isSecure() Check if the value of this number has been secured.
void	secure() Secure the value of this number.
void	setValue(byte value) Set the value of this number.
void	setValue(double value) Set the value of this number.
void	setValue(float value) Set the value of this number.
void	setValue(int value) Set the value of this number.
void	setValue(long value) Set the value of this number.
void	setValue(short value) Set the value of this number.
protected void	setValueInternal(byte value) An internal set command.
protected abstract void	setValueInternal(double value) An internal set command.
protected abstract void	setValueInternal(float value) An internal set command.
protected abstract void	setValueInternal(int value) An internal set command.
protected abstract void	setValueInternal(long value) An internal set command.
protected void	setValueInternal(short value) An internal set command.
protected void	verifyNotSecure() Check the secure flag, throwing an exception if the number is not in a variable state.

Methods inherited from class java.lang.Number

byteValue, doubleValue, floatValue, intValue, longValue, shortValue

Methods inherited from class java.lang.Object

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

Field Detail

secure

private boolean secure

Flag set once the value has been fixed, effectively making the number immutable.

Constructor Detail

VariableNumber

public VariableNumber()

Method Detail

secure

public void secure()

Secure the value of this number.
Once this method has been called, the value is fixed. Calls to the setValue methods will cause an exception.

See Also:

setValue(int), setValue(long), setValue(float), setValue(double), setValue(short), setValue(byte)

isSecure

public boolean isSecure()

Check if the value of this number has been secured.
This method can be used to guard against exceptions being thrown by the setValue methods.

Returns:

true if the value of this number can no longer be changed

See Also:

setValue(int), setValue(long), setValue(float), setValue(double), setValue(short), setValue(byte)

verifyNotSecure

protected void verifyNotSecure()

Check the secure flag, throwing an exception if the number is not in a variable state.

Throws:

IllegalStateException - if this number is no longer in a variable state

setValue

public final void setValue(int value)

Set the value of this number.
If the number is secure an exception will be thrown.

Parameters:

value - the new value for this number

Throws:

IllegalStateException - if this number is no longer in a variable state

See Also:

secure, secure()

setValue

public final void setValue(long value)

Set the value of this number.
If the number is secure an exception will be thrown.

Parameters:

value - the new value for this number

Throws:

IllegalStateException - if this number is no longer in a variable state

See Also:

secure, secure()

setValue

public final void setValue(float value)

Set the value of this number.
If the number is secure an exception will be thrown.

Parameters:

value - the new value for this number

Throws:

IllegalStateException - if this number is no longer in a variable state

See Also:

secure, secure()

setValue

public final void setValue(double value)

Set the value of this number.
If the number is secure an exception will be thrown.

Parameters:

value - the new value for this number

Throws:

IllegalStateException - if this number is no longer in a variable state

See Also:

secure, secure()

setValue

public final void setValue(short value)

Set the value of this number.
If the number is secure an exception will be thrown.

Parameters:

value - the new value for this number

Throws:

IllegalStateException - if this number is no longer in a variable state

See Also:

secure, secure()

setValue

public final void setValue(byte value)

Set the value of this number.
If the number is secure an exception will be thrown.

Parameters:

value - the new value for this number

Throws:

IllegalStateException - if this number is no longer in a variable state

See Also:

secure, secure()

setValueInternal

protected abstract void setValueInternal(int value)

An internal set command.
This function will only be called if the number is still in a variable state.

Parameters:

value - the new value for this number

setValueInternal

protected abstract void setValueInternal(long value)

An internal set command.
This function will only be called if the number is still in a variable state.

Parameters:

value - the new value for this number

setValueInternal

protected abstract void setValueInternal(float value)

An internal set command.
This function will only be called if the number is still in a variable state.

Parameters:

value - the new value for this number

setValueInternal

protected abstract void setValueInternal(double value)

An internal set command.
This function will only be called if the number is still in a variable state.

Parameters:

value - the new value for this number

setValueInternal

protected void setValueInternal(short value)

An internal set command.
This function will only be called if the number is still in a variable state.

Parameters:

value - the new value for this number

setValueInternal

protected void setValueInternal(byte value)

An internal set command.
This function will only be called if the number is still in a variable state.

Parameters:

value - the new value for this number