https://github.com/brucewind/juao

🚄 fast cache much more than JVM heap memory in Android.(在安卓上利用更多的物理RAM,快速地存取巨量的Java对象)
https://github.com/brucewind/juao

android bitmap bitmap-cache cache-storage java memory-cache memory-hacking

Last synced: 7 months ago
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🚄 fast cache much more than JVM heap memory in Android.(在安卓上利用更多的物理RAM,快速地存取巨量的Java对象)

• Host: GitHub
• URL: https://github.com/brucewind/juao
• Owner: BruceWind
• License: apache-2.0
• Created: 2020-03-05T10:07:31.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2024-01-05T13:46:05.000Z (about 2 years ago)
• Last Synced: 2025-04-22T06:42:02.311Z (9 months ago)
• Topics: android, bitmap, bitmap-cache, cache-storage, java, memory-cache, memory-hacking
• Language: Java
• Homepage:
• Size: 1.35 MB
• Stars: 8
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

          
# Juao ![Build APK](https://github.com/BruceWind/Juao/workflows/Build%20APK/badge.svg?branch=master)![runUnitTest](https://github.com/BruceWind/Juao/workflows/runUnitTest/badge.svg)

[中文](https://github.com/BruceWind/Juao/blob/master/README_zh.md)

> [Juao](https://www.wikiwand.com/zh-cn/%E9%B3%8C) (巨鳌), a hugest animal in traditonal Chinese legend, looks like a tortoise could float up moutain or land from the ocean.

![](https://github.com/BruceWind/Juao/raw/master/image/juao.png)

In most Android devices, enven though the physical memory (RAM) is very large, but often the memory that app can use is not much more than [JVM heap size](https://developer.android.com/topic/performance/memory#CheckHowMuchMemory).

When you have a huge amount of memory that needs to calculate on Android, may you think your can't alloc enough memory.

So I made this library. (It is fact that just few people get in the situation.)

If you need to deal with super-large image on devices which is lower than Android 8.0, you must need this library.

While your memory is caching in **Juao**, both put and pop will be very fast.

I made an example of caching Bitmap in there. The bitmap put and get from cache is really fast. In the example, I divided a panoramic image into many images, and then merged those to display.

I don't recommend using this repo to cache bitmaps on devices higher than 8.0, because [bitmap pixel data was already stored in native heap when device higher than 8.0](https://developer.android.google.cn/topic/performance/graphics/manage-memory).

In addition, I would enable about 40% of the physical RAM.

Currently,caching for **Bitmap, Parcelable, and Serializable** are supported by **Juao**. It capable of supporting other types. 

I may develop caching byte[] in the future.

## How it work?

Use [DirectByteBuffer](https://chromium.googlesource.com/android_tools/+/2403/sdk/sources/android-22/java/nio/DirectByteBuffer.java) 

 to cache bytes on memory which is physical memory. If cache bytes over limitation that you set, bytes will be cached on disk.