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/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
package com.sun.star.wizards.ui.event;
import java.util.Arrays;
/**
* DataAware objects are used to live-synchronize UI and DataModel/DataObject.
* It is used as listener on UI events, to keep the DataObject up to date.
* This class, as a base abstract class, sets a frame of functionality,
* delegating the data Object get/set methods to a Value object,
* and leaving the UI get/set methods abstract.
* Note that event listenning is *not* a part of this model.
* the updateData() or updateUI() methods should be porogramatically called.
* in child classes, the updateData() will be binded to UI event calls.
* <br><br>
* This class holds references to a Data Object and a Value object.
* The Value object "knows" how to get and set a value from the
* Data Object.
*/
public abstract class DataAware {
/**
* this is the data object.
*/
private Object dataObject;
/**
* A Value Object knows how to get/set a value
* from/to the data object.
*/
private Value value;
/**
* creates a DataAware object for the given data object and Value object.
* @param dataObject_
* @param value_
*/
protected DataAware(Object dataObject_, Value value_) {
dataObject = dataObject_;
value = value_;
}
/**
* returns the data object.
*/
private Object getDataObject() {
return dataObject;
}
/**
* Sets the given value to the data object.
* this method delegates the job to the
* Value object, but can be overwritten if
* another kind of Data is needed.
* @param newValue the new value to set to the DataObject.
*/
private void setToData(Object newValue) {
value.set(newValue,getDataObject());
}
/**
* gets the current value from the data object.
* this method delegates the job to
* the value object.
* @return the current value of the data object.
*/
private Object getFromData() {
return value.get(getDataObject());
}
/**
* sets the given value to the UI control
* @param newValue the value to set to the ui control.
*/
protected abstract void setToUI(Object newValue);
/**
* gets the current value from the UI control.
* @return the current value from the UI control.
*/
protected abstract Object getFromUI();
/**
* enables
* @param currentValue
*/
private void enableControls(Object currentValue) {
}
/**
* updates the DataObject according to
* the current state of the UI control.
*/
public void updateData() {
Object data = getFromData();
Object ui = getFromUI();
if (!equals(data, ui))
setToData(ui);
enableControls(ui);
}
public interface Listener {
void eventPerformed(Object event);
}
/**
* compares the two given objects.
* This method is null safe and returns true also if both are null...
* If both are arrays, treats them as array of short and compares them.
* @param a first object to compare
* @param b second object to compare.
* @return true if both are null or both are equal.
*/
private boolean equals(Object a, Object b) {
if (a == null && b == null)
return true;
if (a == null || b == null)
return false;
if (a.getClass().isArray()) {
if (b.getClass().isArray())
return Arrays.equals((short[]) a, (short[]) b);
else
return false;
}
return a.equals(b);
}
/**
* Value objects read and write a value from and
* to an object. Typically using reflection and JavaBeans properties
* or directly using member reflection API.
* DataAware delegates the handling of the DataObject
* to a Value object.
* 2 implementations currently exist: PropertyValue,
* using JavaBeans properties reflection, and DataAwareFields classes
* which implement different member types.
*/
public interface Value {
/**
* gets a value from the given object.
* @param target the object to get the value from.
* @return the value from the given object.
*/
Object get(Object target);
/**
* sets a value to the given object.
* @param value the value to set to the object.
* @param target the object to set the value to.
*/
void set(Object value, Object target);
}
}
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