/*
* Bibliothek - DockingFrames
* Library built on Java/Swing, allows the user to "drag and drop"
* panels containing any Swing-Component the developer likes to add.
*
* Copyright (C) 2007 Benjamin Sigg
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Benjamin Sigg
* benjamin_sigg@gmx.ch
* CH - Switzerland
*/
package bibliothek.gui.dock.util;
import bibliothek.gui.DockTheme;
/**
* This container holds three versions of the same value, a default, theme and
* a client value. If asked for the value the value with the highest priority
* is returned. Other than {@link PriorityValue} this container also supports
* <code>null</code> as value.
* @author Benjamin Sigg
*
* @param <T> the kind of value stored in this {@link NullPriorityValue}
*/
public class NullPriorityValue<T> {
/** the default value */
private T valueDefault;
private boolean valueDefaultSet = false;
/** the value set by a {@link DockTheme} */
private T valueTheme;
private boolean valueThemeSet = false;
/** the value set by the client */
private T valueClient;
private boolean valueClientSet = false;
/**
* Sets the value for a given priority.
* @param priority the priority of <code>value</code>
* @param value the new value, can be <code>null</code>
* @return <code>true</code> if the result of {@link #get()}
* changes because of the call of this method
*/
public boolean set( Priority priority, T value ){
T old = get();
switch( priority ){
case DEFAULT:
valueDefault = value;
valueDefaultSet = true;
break;
case THEME:
valueTheme = value;
valueThemeSet = true;
break;
case CLIENT:
valueClient = value;
valueClientSet = true;
break;
}
return old != get();
}
/**
* Tells whether at least one version is set.
* @return <code>true</code> if at least some value is set
*/
public boolean isSomethingSet(){
return valueDefaultSet || valueThemeSet || valueClientSet;
}
/**
* Tells whether the value for <code>priority</code> is set.
* @param priority the priority to inquire
* @return <code>true</code> if the value is set
*/
public boolean isSet( Priority priority ){
switch( priority ){
case CLIENT: return valueClientSet;
case DEFAULT: return valueDefaultSet;
case THEME: return valueThemeSet;
default: throw new IllegalArgumentException( "unknown priority: " + priority );
}
}
/**
* Removes the value for <code>priority</code>.
* @param priority the priority to clean
* @return <code>true</code> if the result of {@link #get()}
* changes because of the call to this method
*/
public boolean unset( Priority priority ){
T old = get();
switch( priority ){
case CLIENT:
valueClient = null;
valueClientSet = false;
break;
case DEFAULT:
valueDefault = null;
valueDefaultSet = false;
break;
case THEME:
valueTheme = null;
valueThemeSet = false;
}
return old != get();
}
/**
* Gets the value for a given priority.
* @param priority the priority for which the value is requested
* @return the value that was {@link #set(Priority, Object)} for <code>priority</code>
*/
public T get( Priority priority ){
switch( priority ){
case CLIENT:
return valueClient;
case DEFAULT:
return valueDefault;
case THEME:
return valueTheme;
}
return null;
}
/**
* Gets the current value with the highest priority.
* @return the value or <code>null</code>
*/
public T get(){
if( valueClientSet )
return valueClient;
if( valueThemeSet )
return valueTheme;
if( valueDefaultSet )
return valueDefault;
return null;
}
}