org.nakedobjects.object.value
Class AbstractNakedValue

java.lang.Object
  org.nakedobjects.object.value.AbstractNakedValue

All Implemented Interfaces:

Naked, NakedValue, java.io.Serializable

Direct Known Subclasses:

Currency, Logical, Magnitude, Option, TextString, URLString

public abstract class AbstractNakedValue

extends java.lang.Object

implements NakedValue

See Also:

Serialized Form

Constructor Summary

AbstractNakedValue()

Method Summary

About	about() Returns the objects About object.
void	addNakedValueListener(NakedValueListener l) Registers an object as a listener of this naked value.
protected void	checkCanOperate() Throws an exception if the ojbect is null
java.lang.String	contextualTitle()
AbstractNakedValue	deepCopy() Returns a deep copy of this object.
java.lang.String	dumpObject()
void	fireValueChanged() Overridden version of fireValueChanged(NakedValue) that passes null for the old value.
void	fireValueChanged(NakedValue oldValue) Allows subclasses (indeed any class) to notify listeners when they are about to change the state of the naked value.
java.lang.String	getClassName() Returns the class name without package details e.g., Transaction for the class accounts.Transaction
java.lang.String	getFullClassName() Returns the full class name including package details e.g., accounts.Transaction
protected org.apache.log4j.Logger	getLogger() subclasses can override (didn't make abstract so that existing subclasses won't break)
java.lang.String	getObjectHelpText() Returns a textual desctiption of the object - its contents and possible uses.
boolean	isNull() Deprecated.
boolean	isValid() Returns true if the object contains valid data
java.util.Enumeration	nakedValueListeners() Returns enumeration of all registered naked value listeners
void	removeNakedValueListener(NakedValueListener l) Removes an object as a listener of this naked value.
void	setAbout(About newAbout)
void	setNull() Deprecated.
void	setValidity(Validity strategy)
java.lang.String	summary() Returns a String summarising the state of the object.
java.lang.String	toString() Returns a string representation of this object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.nakedobjects.object.NakedValue

clear, parse, reset, restoreString, saveString

Methods inherited from interface org.nakedobjects.object.Naked

copyObject, isEmpty, isSameAs, title

Constructor Detail

AbstractNakedValue

public AbstractNakedValue()

Method Detail

getLogger

protected org.apache.log4j.Logger getLogger()

subclasses can override (didn't make abstract so that existing subclasses won't break)

about

public About about()

Returns the objects About object. If none is set up then it returns the default one, namely FieldAbout.READ_WRITE

Specified by:

about in interface Naked

checkCanOperate

protected void checkCanOperate()

Throws an exception if the ojbect is null

contextualTitle

public java.lang.String contextualTitle()

dumpObject

public java.lang.String dumpObject()

getClassName

public java.lang.String getClassName()

Description copied from interface: Naked

Returns the class name without package details e.g., Transaction for the class accounts.Transaction

Specified by:

getClassName in interface Naked

getFullClassName

public java.lang.String getFullClassName()

Description copied from interface: Naked

Returns the full class name including package details e.g., accounts.Transaction

Specified by:

getFullClassName in interface Naked

getObjectHelpText

public java.lang.String getObjectHelpText()

Description copied from interface: Naked

Returns a textual desctiption of the object - its contents and possible uses.

Specified by:

getObjectHelpText in interface Naked

isNull

public boolean isNull()

Deprecated.

Specified by:

isNull in interface NakedValue

See Also:

Naked.isEmpty()

isValid

public boolean isValid()

Description copied from interface: Naked

Returns true if the object contains valid data

Specified by:

isValid in interface Naked

setAbout

public void setAbout(About newAbout)

setNull

public void setNull()

Deprecated.

Specified by:

setNull in interface NakedValue

See Also:

NakedValue.clear()

setValidity

public void setValidity(Validity strategy)

summary

public java.lang.String summary()

Description copied from interface: Naked

Returns a String summarising the state of the object.

Specified by:

summary in interface Naked

toString

public java.lang.String toString()

Returns a string representation of this object.

The specification of this string representation is not fixed, but, at the time of writing, consists of title [shortNakedClassName]

Returns:

string representation of object.

addNakedValueListener

public final void addNakedValueListener(NakedValueListener l)

Registers an object as a listener of this naked value. Whenever the naked value's state changes, then all listeners will be notified.

CAVEAT: only objects that are resolved and instantiated will be notified. In general, this means that it is okay for the owning object of a naked value to register itself as a listener, but not for other objects unless it can be arranged for them to have already been resolved from the object store.

removeNakedValueListener

public final void removeNakedValueListener(NakedValueListener l)

Removes an object as a listener of this naked value. The listener will no longer be notified of changes to the naked value's state.

fireValueChanged

public final void fireValueChanged(NakedValue oldValue)

Allows subclasses (indeed any class) to notify listeners when they are about to change the state of the naked value. Typical usage is:

• call deepCopy() on self to obtain current (old) value
• modify self
• call notifyListenersChanged(NakedValue) passing the old value from first step.

See Also:

deepCopy()

fireValueChanged

public final void fireValueChanged()

Overridden version of fireValueChanged(NakedValue) that passes null for the old value.

This was added since it was noted that some value objects are not in fact serializable.

See Also:

fireValueChanged(NakedValue)

nakedValueListeners

public final java.util.Enumeration nakedValueListeners()

Returns enumeration of all registered naked value listeners

deepCopy

public final AbstractNakedValue deepCopy()

Returns a deep copy of this object.

Alternatively, could have implemented clone(). However, that is a much misunderstood method.

Implementation note: exploits fact that AbstractNakedValue is serializable. Serializes the object to a byte stream, and the deserializes.

See Also:

Serializable, Object.clone()