LocationCacheAspect.java
/*
** Module : LocationCacheAspect.java
** Abstract : An aspect which intercepts APIs related to screen location cache.
**
** Copyright (c) 2018-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 CA 20180208 Created initial version.
** 002 CA 20180209 A fix - iajc compiler requires absolute names in the aspect definition.
** 003 HC 20240806 Added support for displaying frame widget in an overlay window.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
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** attribution required in this license.
*/
package com.goldencode.p2j.aspects.ui;
import org.aspectj.lang.*;
import org.aspectj.lang.annotation.*;
import com.goldencode.p2j.ui.client.*;
import com.goldencode.p2j.ui.client.widget.*;
/**
* This aspects takes care of intercepting the APIs which require to either cache the screen
* location values or disable the caching for them. This includes:
* <ul>
* <li>disabling and/or reseting the cached values when layout is performed.</li>
* <li>caching these values (as appropriate) when the {@link Widget#screenLocation()} and
* {@link Widget#screenPhysicalLocation()} APIs are executed.</li>
* </ul>
*/
@Aspect()
public class LocationCacheAspect
{
/**
* Tracks the depth of layout-related nested API calls. When is zero, it will force the
* {@link AbstractWidget#reflectLocationChanged() cached values to be reset.}
*/
private static int layoutDepth = 0;
/**
* Executed around the {@link com.goldencode.p2j.ui.client.layout.LayoutManager} APIs, keeping
* track of the nested depth via {@link #layoutDepth}.
* <p>
* Before executing the API, it will reset any cached location values.
*
* @param thisJoinPoint
* A join point reference.
* @param container
* The container parameter instance.
*
* @return The value of the join point method.
*
* @throws Throwable
* Any exceptions are untouched propagated out.
*/
@Around("args(container) " +
" && execution(public void com.goldencode.p2j.ui.client.layout.LayoutManager+.*(..))")
public Object disableLocationCacheForLayout(ProceedingJoinPoint thisJoinPoint,
Container<?> container)
throws Throwable
{
AbstractWidget<?> widget = (AbstractWidget<?>) container;
if (layoutDepth == 0)
{
// ensure nothing is cached
widget.reflectLocationChanged();
}
layoutDepth += 1;
try
{
return thisJoinPoint.proceed();
}
finally
{
// no need to reflectLocationChange, as nothing gets cached while the depth is non-zero
layoutDepth -= 1;
}
}
/**
* Executed around the {@link Container#doLayout()} and related APIs, keeping track of the
* nested depth via {@link #layoutDepth}.
* <p>
* Before executing the API, it will reset any cached location values.
*
* @param thisJoinPoint
* A join point reference.
*
* @return The value of the join point method.
*
* @throws Throwable
* Any exceptions are untouched propagated out.
*/
@Around("execution(public void com.goldencode.p2j.ui.client.widget.Container+.doLayout()) " +
" || execution(protected void com.goldencode.p2j.ui.client.Frame+.doLayoutWorker(boolean))")
public Object disableLocationCacheInContainer(ProceedingJoinPoint thisJoinPoint)
throws Throwable
{
AbstractWidget<?> widget = (AbstractWidget<?>) thisJoinPoint.getThis();
if (layoutDepth == 0)
{
// ensure nothing is cached
widget.reflectLocationChanged();
}
layoutDepth += 1;
try
{
return thisJoinPoint.proceed();
}
finally
{
// no need to reflectLocationChange, as nothing gets cached while the depth is non-zero
layoutDepth -= 1;
}
}
/**
* Executed around the {@link Widget#screenLocation()} API. If the widget has an already
* cached value and the {@link #layoutDepth} is zero, it will use it. Otherwise, it will
* compute it and cache it (if {@link #layoutDepth} is zero).
*
* @param thisJoinPoint
* A join point reference.
*
* @return The value of the join point method.
*
* @throws Throwable
* Any exceptions are untouched propagated out.
*/
@Around("execution(public com.goldencode.p2j.ui.client.Point " +
"com.goldencode.p2j.ui.client.widget.Widget+.screenLocation())")
public Object cacheScreenLocation(ProceedingJoinPoint thisJoinPoint)
throws Throwable
{
AbstractWidget<?> widget = (AbstractWidget<?>) thisJoinPoint.getThis();
if (layoutDepth == 0)
{
Point cached = widget.getCachedScreenLocation();
if (cached != null)
{
return cached;
}
}
Point location = (Point) thisJoinPoint.proceed();
if (layoutDepth == 0)
{
widget.setCachedScreenLocation(location);
}
return location;
}
/**
* Executed around the {@link Widget#screenPhysicalLocation()} API. If the widget has an already
* cached value and the {@link #layoutDepth} is zero, it will use it. Otherwise, it will
* compute it and cache it (if {@link #layoutDepth} is zero).
*
* @param thisJoinPoint
* A join point reference.
*
* @return The value of the join point method.
*
* @throws Throwable
* Any exceptions are untouched propagated out.
*/
@Around("execution(public com.goldencode.p2j.ui.client.NativePoint " +
"com.goldencode.p2j.ui.client.widget.Widget+.screenPhysicalLocation())")
public Object cacheScreenPhysicalLocation(ProceedingJoinPoint thisJoinPoint)
throws Throwable
{
AbstractWidget<?> widget = (AbstractWidget<?>) thisJoinPoint.getThis();
if (layoutDepth == 0)
{
NativePoint cached = widget.getCachedScreenPhysicalLocation();
if (cached != null)
{
return cached;
}
}
NativePoint location = (NativePoint) thisJoinPoint.proceed();
if (layoutDepth == 0)
{
widget.setCachedScreenPhysicalLocation(location);
}
return location;
}
}