/*
* Copyright (c) 2007, 2009, 2011, 2012 Eike Stepper (Berlin, Germany) and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Eike Stepper - initial API and implementation
*/
package org.eclipse.net4j.internal.util.om.pref;
import org.eclipse.net4j.util.ObjectUtil;
import org.eclipse.net4j.util.om.pref.OMPreference;
/**
* @author Eike Stepper
*/
public abstract class Preference<T> implements OMPreference<T>
{
private Preferences preferences;
private String name;
private T defaultValue;
private T value;
public Preference(Preferences preferences, String name, T defaultValue)
{
if (defaultValue == null)
{
throw new IllegalArgumentException("defaultValue == null"); //$NON-NLS-1$
}
this.preferences = preferences;
this.name = name;
this.defaultValue = defaultValue;
}
public Preferences getPreferences()
{
return preferences;
}
public String getName()
{
return name;
}
public T getDefaultValue()
{
return defaultValue;
}
public T getValue()
{
load();
return value;
}
public T setValue(T value)
{
if (value == null)
{
throw new IllegalArgumentException("value == null"); //$NON-NLS-1$
}
load();
T oldValue = this.value;
if (!equals(oldValue, value))
{
if (equals(defaultValue, value))
{
value = defaultValue;
}
this.value = value;
preferences.fireChangeEvent(this, oldValue, value);
return oldValue;
}
return null;
}
public boolean isSet()
{
return !equals(defaultValue, value);
}
public T unSet()
{
return setValue(defaultValue);
}
@Override
public String toString()
{
return getName() + " = " + getValue();
}
protected boolean equals(T v1, T v2)
{
return ObjectUtil.equals(v1, v2);
}
protected void init(String value)
{
if (value == null)
{
this.value = defaultValue;
}
else
{
this.value = convert(value);
}
}
protected abstract T convert(String value);
protected abstract String getString();
private void load()
{
preferences.load();
}
}