org.xnap.util
Class AbstractPreferences

java.lang.Object
  org.xnap.util.AbstractPreferences

Direct Known Subclasses:

Preferences

public abstract class AbstractPreferences
extends java.lang.Object

This class provides a default implementation for a preferences framework. Methods are provided that can read and write native types, arrays and a few custom types.

Field Summary

static java.lang.String	ARRAY_SEPARATOR
protected boolean	changedFlag Determines if preferences need to be saved.
protected static org.apache.log4j.Logger	logger
protected java.lang.String	namespace The namespace is prefixed to each key.
protected int	oldVersion Version of database when read.
protected java.io.File	prefsFile Preferences database.
protected java.beans.PropertyChangeSupport	propertyChange
protected java.util.Properties	props Preferences.
protected int	version Version of database format.

Constructor Summary

AbstractPreferences(java.lang.String filename, int version, java.lang.String namespace)
Constructs a PreferencesSupport object.

Method Summary

void	addPropertyChangeListener(java.beans.PropertyChangeListener l) Adds a preferences listener.
void	addPropertyChangeListener(java.lang.String key, java.beans.PropertyChangeListener l) Adds a preferences listener for a specific key.
static boolean	areObjectsEqual(java.lang.Object[] obj1, java.lang.Object[] obj2) Determine if 2 arrays are equal, or both point to null.
static boolean	areObjectsEqual(java.lang.Object obj1, java.lang.Object obj2) Determine if 2 objects are equal, or both point to null.
abstract void	convert(int oldVersion) Invoked by read() to converts preferences from oldVersion to current version.
void	firePropertyChange(java.lang.String key, java.lang.Object oldValue, java.lang.Object newValue) Fires PropertyChangeEvent without namespace.
java.lang.String	get(java.lang.String key)
java.lang.String[]	getArray(java.lang.String key)
boolean	getBoolean(java.lang.String key)
java.awt.Color	getColor(java.lang.String key)
java.lang.String	getFilename() Returns the absolute path of the preferences file.
java.awt.Font	getFont(java.lang.String key) Always returns a valid font.
int	getInt(java.lang.String key) Reads an integer from the properties.
int[]	getIntArray(java.lang.String key)
javax.swing.KeyStroke	getKeyStroke(java.lang.String key) Reads a keystroke from the properties.
long	getLong(java.lang.String key)
int	getOldVersion() Returns the version of the preferences in the file at the point of the last read operation.
protected java.lang.String	getProperty(java.lang.String key, java.lang.String defaultValue) Returns a property.
int	getVersion() Returns the current version of the preferences.
void	read() Reads preferences from default preferences file.
void	read(java.io.File f) Reads preferences from f.
void	removeProperty(java.lang.String key) Ignores namespace.
void	removePropertyChangeListener(java.beans.PropertyChangeListener l) Removes a preferences listener.
void	removePropertyChangeListener(java.lang.String key, java.beans.PropertyChangeListener l)
void	renameProperty(java.lang.String oldKey, java.lang.String newKey) Renames a property, used for conversion of property file formats.
void	set(java.lang.String key, boolean newValue)
void	set(java.lang.String key, java.awt.Color newValue)
void	set(java.lang.String key, java.awt.Font newValue) Saves a font.
void	set(java.lang.String key, int newValue)
void	set(java.lang.String key, int[] newValue)
void	set(java.lang.String key, javax.swing.KeyStroke newValue)
void	set(java.lang.String key, long newValue)
void	set(java.lang.String key, java.lang.String newValue)
void	set(java.lang.String key, java.lang.String[] newValue)
void	setDefault(java.lang.String key, java.lang.String value) Sets a default property.
void	setDefault(java.lang.String key, java.lang.String value, Validator validator) Sets a default property.
protected void	setProperty(java.lang.String key, java.lang.String newValue) Sets a property.
protected void	setProperty(java.lang.String key, java.lang.String newValue, boolean validate) Sets a property.
static java.lang.String	toString(java.awt.Font font)
static java.lang.String	toString(javax.swing.KeyStroke keystroke)
boolean	write() Writes preferences to default preferences file.

Methods inherited from class java.lang.Object

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

Field Detail

ARRAY_SEPARATOR

public static final java.lang.String ARRAY_SEPARATOR

See Also:

Constant Field Values

logger

protected static org.apache.log4j.Logger logger

propertyChange

protected transient java.beans.PropertyChangeSupport propertyChange

changedFlag

protected boolean changedFlag

Determines if preferences need to be saved.

prefsFile

protected java.io.File prefsFile

Preferences database.

version

protected int version

Version of database format.

oldVersion

protected int oldVersion

Version of database when read.

namespace

protected java.lang.String namespace

The namespace is prefixed to each key.

props

protected java.util.Properties props

Preferences.

Constructor Detail

AbstractPreferences

public AbstractPreferences(java.lang.String filename,
                           int version,
                           java.lang.String namespace)

Constructs a PreferencesSupport object.

Parameters:

filename - the filename of the preferences file

version - the current version of the preferences, this version can be more recent than the version of the file

namespace - the namespace, used as a prefix for all keys

Method Detail

getFilename

public java.lang.String getFilename()

Returns the absolute path of the preferences file.

read

public void read(java.io.File f)

Reads preferences from f.

read

public void read()

Reads preferences from default preferences file.

write

public boolean write()

Writes preferences to default preferences file. If preferences have not changed since the last read or write operation, no action is taken.

Returns:

true, if file is written successfully or preferences were not changed; false, if an IOException has occured

getOldVersion

public int getOldVersion()

Returns the version of the preferences in the file at the point of the last read operation.

getVersion

public int getVersion()

Returns the current version of the preferences.

convert

public abstract void convert(int oldVersion)

Invoked by read() to converts preferences from oldVersion to current version.

addPropertyChangeListener

public void addPropertyChangeListener(java.beans.PropertyChangeListener l)

Adds a preferences listener.

addPropertyChangeListener

public void addPropertyChangeListener(java.lang.String key,
                                      java.beans.PropertyChangeListener l)

Adds a preferences listener for a specific key.

firePropertyChange

public void firePropertyChange(java.lang.String key,
                               java.lang.Object oldValue,
                               java.lang.Object newValue)

Fires PropertyChangeEvent without namespace.

removePropertyChangeListener

public void removePropertyChangeListener(java.beans.PropertyChangeListener l)

Removes a preferences listener.

removePropertyChangeListener

public void removePropertyChangeListener(java.lang.String key,
                                         java.beans.PropertyChangeListener l)

get

public java.lang.String get(java.lang.String key)

getArray

public java.lang.String[] getArray(java.lang.String key)

getBoolean

public boolean getBoolean(java.lang.String key)

getColor

public java.awt.Color getColor(java.lang.String key)

getFont

public java.awt.Font getFont(java.lang.String key)

Always returns a valid font.

getKeyStroke

public javax.swing.KeyStroke getKeyStroke(java.lang.String key)

Reads a keystroke from the properties.

Returns:

null, if key was not found or value is invalid

getInt

public int getInt(java.lang.String key)

Reads an integer from the properties.

Returns:

0, if conversion fails; the value, otherwise

getIntArray

public int[] getIntArray(java.lang.String key)

getLong

public long getLong(java.lang.String key)

set

public void set(java.lang.String key,
                java.lang.String newValue)

set

public void set(java.lang.String key,
                java.lang.String[] newValue)

set

public void set(java.lang.String key,
                boolean newValue)

set

public void set(java.lang.String key,
                java.awt.Color newValue)

set

public void set(java.lang.String key,
                java.awt.Font newValue)

Saves a font.

set

public void set(java.lang.String key,
                int newValue)

set

public void set(java.lang.String key,
                int[] newValue)

set

public void set(java.lang.String key,
                javax.swing.KeyStroke newValue)

set

public void set(java.lang.String key,
                long newValue)

setDefault

public void setDefault(java.lang.String key,
                       java.lang.String value,
                       Validator validator)

Sets a default property. If key already exists the value is not overwritten.

If a key already exists, the corresponding value is validated by validator and will replaced by value if the validation fails.

Parameters:

key - the key

value - the default value

validator - a validator that is invoked each time a value is set

setDefault

public void setDefault(java.lang.String key,
                       java.lang.String value)

Sets a default property. If key already exists the value is not overwritten.

Parameters:

key - the key

value - the default value

removeProperty

public void removeProperty(java.lang.String key)

Ignores namespace.

renameProperty

public void renameProperty(java.lang.String oldKey,
                           java.lang.String newKey)

Renames a property, used for conversion of property file formats. Ignores namespace. Does not fire change event.

getProperty

protected java.lang.String getProperty(java.lang.String key,
                                       java.lang.String defaultValue)

Returns a property.

setProperty

protected void setProperty(java.lang.String key,
                           java.lang.String newValue,
                           boolean validate)

Sets a property. newValue is validated if validate is set to true and a validator has been provided.

Parameters:

key - the key to set

newValue - the value to set

validate - if true, newValue will be validated

Throws:

java.lang.IllegalArgumentException - if newValue is not valid

setProperty

protected void setProperty(java.lang.String key,
                           java.lang.String newValue)

Sets a property. newValue is validated if a validator has been provided.

Parameters:

key - the key to set

newValue - the value to set

See Also:

setProperty(String, String, boolean)

areObjectsEqual

public static boolean areObjectsEqual(java.lang.Object obj1,
                                      java.lang.Object obj2)

Determine if 2 objects are equal, or both point to null.

areObjectsEqual

public static boolean areObjectsEqual(java.lang.Object[] obj1,
                                      java.lang.Object[] obj2)

Determine if 2 arrays are equal, or both point to null.

toString

public static java.lang.String toString(java.awt.Font font)

toString

public static java.lang.String toString(javax.swing.KeyStroke keystroke)