/*
* Copyright (c) 2012, Codename One and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Codename One designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Codename One through http://www.codenameone.com/ if you
* need additional information or have any questions.
*/
package com.codename1.properties;
import java.util.ArrayList;
import java.util.List;
/**
* Base class for property types
*
* @author Shai Almog
*/
public class PropertyBase<T, K> {
private final String name;
private Class genericType;
private ArrayList<PropertyChangeListener<T, K>> listeners;
PropertyIndex parent;
private static PropertyChangeListener lastChangeListener;
/**
* All properties must have a name
* @param name the name of the property
*/
protected PropertyBase(String name) {
this.name = name;
}
/**
* Provides the internal list of listeners
* @return internal list of listeners
*/
List<PropertyChangeListener<T, K>> getListeners() {
return listeners;
}
/**
* All properties must have a name, a generic type is helpful
* @param name the name of the property
* @param genericType the property type to workaround issues with erasure
*/
protected PropertyBase(String name, Class genericType) {
this.name = name;
this.genericType = genericType;
}
/**
* The property name is immutable and can't be changed after creation it should match the parent field name by convention
* @return the property name;
*/
public String getName() {
return name;
}
/**
* Delivers the property change event to listeners if applicable
*/
protected void firePropertyChanged() {
if(listeners != null) {
for(PropertyChangeListener pl : listeners) {
lastChangeListener = pl;
pl.propertyChanged(this);
lastChangeListener = null;
}
}
}
/**
* This method will work when invoked from a propertyChanged callback and should be similar to
* {@code removePropertyChangeListener(this)}. It's useful for lambda's where {@code this}
* means the base class and not the listener so {@code removePropertyChangeListener(this)}
* won't do what we want unless we convert to an inner class
*/
public void stopListening() {
removeChangeListener(lastChangeListener);
}
/**
* Fires a notification that a property value changed to the given listener
* @param pl the listener
*/
public void addChangeListener(PropertyChangeListener<T, K> pl) {
if(listeners == null) {
listeners = new ArrayList<PropertyChangeListener<T, K>>();
}
listeners.add(pl);
}
/**
* Removes the property change listener from the list of listeners
* @param pl the change listener
*/
public void removeChangeListener(PropertyChangeListener<T, K> pl) {
if(listeners != null) {
listeners.remove(pl);
if(listeners.size() == 0) {
listeners = null;
}
}
}
/**
* Places a property that will apply statically to all instances of this property
* @param key the key to put
* @param o the value object
*/
public void putClientProperty(String key, Object o) {
parent.putMetaDataOfClass("cn1$field" + name + "-" + key, o);
}
/**
* Returns the client property set to this property name
* @param key the key of the property
* @return the value that was previously placed with put client property
*/
public Object getClientProperty(String key) {
return parent.getMetaDataOfClass("cn1$field" + name + "-" + key);
}
/**
* Compares this property to another property
* @param obj the other property
* @return true if they are equal in name and value
*/
@Override
public boolean equals(Object obj) {
if(obj != null && obj.getClass() == getClass()) {
PropertyBase other = (PropertyBase)obj;
if(other.getName().equals(name)) {
return true;
}
}
return false;
}
T get() {
return null;
}
void setImpl(Object val) {
}
/**
* Default toString that provides easier debug information
* @return a formatted representation of the property for debugging
*/
public String toString() {
T o = get();
if(o == null) {
return getName() + " = null";
}
return getName() + " = '" + o + "' : " +o.getClass().getName();
}
/**
* Returns the generic type of this property if it is known or null
* @return the generic type
*/
public Class getGenericType() {
return genericType;
}
/**
* The label of the property defaults to its name but can be changed to anything, it can be used
* when binding a property to UI elements
* @param label the new label value
*/
public void setLabel(String label) {
putClientProperty("cn1PropertyLabel", label);
}
/**
* The label of the property defaults to its name but can be changed to anything
*
* @return the label for the property
*/
public String getLabel() {
String l = (String)getClientProperty("cn1PropertyLabel");
if(l == null) {
return getName();
}
return l;
}
}