/*
* Copyright (c) 2008, 2010, Oracle 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. Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores
* CA 94065 USA or visit www.oracle.com if you need additional information or
* have any questions.
*/
package com.codename1.components;
import com.codename1.ui.Display;
import com.codename1.ui.EncodedImage;
import com.codename1.ui.Image;
import com.codename1.io.FileSystemStorage;
import com.codename1.io.Log;
import com.codename1.io.Util;
import java.io.InputStream;
import java.util.Vector;
/**
* This class is identical to FileEncodedImage with the difference of using
* asynchronous loading for files (and the animation framework) which will
* not work for all cases (e.g. renderers) but could improve some performance/RAM
* aspects.
*
* @author Shai Almog
*/
public class FileEncodedImageAsync extends EncodedImage {
private String fileName;
private boolean changePending;
private boolean imageCreated;
private byte[] imageData;
private byte[] placeholder;
private Image placeholderImage;
private boolean queued;
private static final Object LOCK = new Object();
private FileEncodedImageAsync(String fileName, byte[] placeholder, int w, int h) {
super(w, h);
this.fileName = fileName;
this.placeholder = placeholder;
}
private FileEncodedImageAsync(String fileName, Image placeholderImage) {
super(placeholderImage.getWidth(), placeholderImage.getHeight());
this.fileName = fileName;
this.placeholderImage = placeholderImage;
}
/**
* {@inheritDoc}
*/
protected void resetCache() {
super.resetCache();
}
/**
* {@inheritDoc}
*/
protected Image getInternal() {
if(imageData == null) {
if(!queued) {
getImageData();
}
return placeholderImage;
}
imageCreated = true;
return super.getInternal();
}
/**
* {@inheritDoc}
*/
public byte[] getImageData() {
if(imageData != null) {
return imageData;
}
synchronized(LOCK) {
if(queued) {
return placeholder;
}
queued = true;
Display.getInstance().scheduleBackgroundTask(new Runnable() {
public void run() {
InputStream i = null;
try {
final byte[] imageDataLocal = new byte[(int) FileSystemStorage.getInstance().getLength(fileName)];
i = FileSystemStorage.getInstance().openInputStream(fileName);
Util.readFully(i, imageDataLocal);
i.close();
// we need to change the image on the EDT to avoid potential race conditions
Display.getInstance().callSerially(new Runnable() {
public void run() {
imageData = imageDataLocal;
resetCache();
changePending = true;
imageCreated = false;
}
});
} catch (Throwable ex) {
Log.e(ex);
} finally {
queued = false;
Util.cleanup(i);
}
}
});
}
if(placeholderImage != null) {
return null;
}
return placeholder;
}
/**
* {@inheritDoc}
*/
public boolean animate() {
if(changePending) {
if(imageCreated) {
changePending = false;
}
return true;
}
return false;
}
/**
* {@inheritDoc}
*/
public boolean isAnimation() {
return true;
}
/**
* Creates an encoded image that maps to a local file thus allowing to
* seamlessly fetch files as needed. This only works reasonably well for very small
* files.
*
* @param fileName the name of the file
* @param placeholder a placeholder image until the actual image loads
* @param width the width of the file or -1 if unknown (notice that this will improve performance)
* @param height the height of the file or -1 if unknown (notice that this will improve performance)
* @return image that will load the file seamlessly
* @deprecated use the version that accepts a name and a placeholderImage
*/
public static FileEncodedImageAsync create(String fileName, byte[] placeholder, int width, int height) {
return new FileEncodedImageAsync(fileName, placeholder, width, height);
}
/**
* Creates an encoded image that maps to a local file thus allowing to
* seamlessly fetch files as needed. This only works reasonably well for very small
* files.
*
* @param fileName the name of the file
* @param placeholder an image that will occupy the space
* @return image that will load the file seamlessly
*/
public static FileEncodedImageAsync create(String fileName, Image placeholder) {
return new FileEncodedImageAsync(fileName, placeholder);
}
}