illegal forware reference in java

case 1:  比較常見的
class Test {
  String s = "hello";

  class inner {
    inner () {
        String s = s;  // <- illegal forward reference
    }
  }
}


case 2:  比較特別的 即使sStr是static也會


class Test2 {
  static {
    System.out.println(sStr);  // <- illegal forward reference
  }

  private static String sStr = "hello World";
}

android emulator support

SMS
    - external/qemu/telephony/modem_driver.c
    see http://developer.android.com/guide/developing/tools/emulator.html#sms for usage

MMS
    - N/A

Geolocation/GPS
    - external/qemu/android/gps.[c|h]

    - how to set
        - ddms :
            Emulator Control -> Location Controls -> {Manual, GPX, KML}

        - shell:
            $>telnet localhost
            gps fix
      
Sensor
    emulator has defined 4 sensors
    - acceleration
    - magnetic_field
    - orientation
    - temperature
    only accelerometer is enable, others need to be tested
    see external/qemu/android/hw-sensors.[c|h]
        external/qemu/android/avd/hardware-properties.ini
    for the changing orientation in emulator( Ctrl + F11),
    Android framework computes the orientation by looking at the accelerometer
    see external/qemu/android/hw-sensors.c _hwSensors_setCoarseOrientation

    for the measure units, see hardware/libhardware/include/hardware/sensors.h
  
Camera
    it forks a preview thread, and keeps generating a YUV422 SurfaceView

    see
    - frameworks/base/camera/libcameraservice/FakeCameara.[cpp|h]
    - frameworks/base/camera/libcameraservice/CameraHardwareStub.[cpp|h]
    to modify it to generate different preview screen


Vibration
    not implemented in emulator
    external/qemu/android/hw-control.c # hw_control_do_query only handles power:light:brightness
    and see /sys/class/timed_output/vibrator/enable on device

Backlight
    - external/qemu/android/hw-control.c

    there are 3 kinds of backlight:
        - lcd_backlight
        - keyboard_backlight
        - button_backlight
    but 'Documents' says only lcd_backlight is supported
    see extenal/qemu/docs/ANDROID-QEMUD-SERVICES.TXT #hw-control services

    but actually even lcd_backlight can not work
    because hardware module 'LIGHTS_HARDWARE_MODULE_ID' is only available when
    TARGET_BOARD_PLATFORM is msm7k or qsd8k_dirs
    see hardware/
  
    also see /sys/class/leds on device

Battery Level
    the implementation is in external/qemu/hw/goldfish_battery.c
    - adb shell dumpsys battery

    also it will create a file /sys/class/power_supply/battery on device

Signal Strength
    the implementation is in external/qemu/telephony/android_modem.c
    see the line
    '{ "+CSQ", "+CSQ: 7,99", NULL },  /* XXX: TODO: implement variable signal strength and error rates */'
    modify 7 to change to signal strength

CPU frequency
    N/A
    but we can get cpu usage by issuing adb
    - adb shell dumpsys cpuinfo

    before cupcake, in Development.apk, there's a option for displaying cpu usage on screen,
    but this isn't supported anymore
    see frameworks/base/libs/surfaceflinger/SurfaceFlinger.cpp  #SurfaceFlinger::onTransact

在dalvik跟v8中把jit code印出來

dalvik
 mydroid/dalvik/vm/Init.c
   see gDvmJit.printMe = true;


v8
mydroid/external/v8/src/flag-definitions.h
print_code
print_builtin_code

android kernel qemu-armv7

http://groups.google.com/group/android-ndk/browse_thread/thread/a19fc6df3d661d79?hl=en

在mydroid build D8

這篇有問題  是錯的

後來發現 d8 中JS2C要的是
把d8.js 轉成d8-js.cc

原因是d8.cc裡面用的是NativesCollection
而這就在產生的d8-js.cc裡




# ===================================================
LOCAL_MODULE := d8
LOCAL_MODULE_CLASS := EXECUTABLES
intermediates := $(call local-intermediates-dir)

include $(LOCAL_PATH)/Android.v8common.mk
LOCAL_JS_LIBRARY_FILES := $(addprefix $(LOCAL_PATH)/,1 $(V8_LOCAL_JS_LIBRARY_FILES))

# Copy js2c.py to intermediates directory and invoke there to avoid generating
# jsmin.pyc in the source directory
JS2C_PY := $(intermediates)/js2c.py $(intermediates)/jsmin.py
$(JS2C_PY): $(intermediates)/%.py : $(LOCAL_PATH)/tools/%.py | $(ACP)
@echo "Copying $@"
$(copy-file-to-target)

# Generate libraries.cc
GEN3 := $(intermediates)/libraries-d8.cc $(intermediates)/libraries-d8-empty.cc
$(GEN3): SCRIPT := $(intermediates)/js2c.py
$(GEN3): $(LOCAL_JS_LIBRARY_FILES) $(JS2C_PY)
 @echo "Generating XXXX libraries.cc"
@mkdir -p $(dir $@)
python $(SCRIPT) $(GEN3) D8 $(LOCAL_JS_LIBRARY_FILES)
V8_GENERATED_LIBRARIES := $(intermediates)/libraries-d8-empty.cc
LOCAL_GENERATED_SOURCES += $(V8_GENERATED_LIBRARIES)

LOCAL_SRC_FILES := src/d8.cc src/d8-debug.cc src/d8-posix.cc
LOCAL_CFLAGS := -DENABLE_DEBUGGER_SUPPORT
ifeq ($(TARGET_ARCH),arm)
    LOCAL_CFLAGS += -DARM -DV8_TARGET_ARCH_ARM
endif


LOCAL_C_INCLUDES := bionic/libc/include $(LOCAL_PATH)/src $(LOCAL_PATH)/include
LOCAL_CPP_EXTENSION := .cc
LOCAL_STATIC_LIBRARIES := libv8
LOCAL_SHARED_LIBRARIES := libcutils

include $(BUILD_EXECUTABLE)

HTML5 Websocket 筆記 2010-07-06

Reply

12:23 pm

HTML5 Websocket 筆記 2010-07-06
Speaker - Chia-Liang Kao, clkao
http://clkao.vox.com/
Websocket API
http://dev.w3.org/html5/websockets/
Websocket protocol
http://www.whatwg.org/specs/web-socket-protocol/
WebSocket的應用
- plurk
- facebook
Websocket出現前 Server跟Client溝通的技術
- Ajax
- Comet (http://en.wikipedia.org/wiki/Comet_(programming))
(兩個名字來源其實都是美國知名的清潔劑品牌 像魔術靈之類的)
Websocket的URI
ws://XXXhost.com
wss://XXXhost.com (多個s代表用了SSL)
WebSocket目前不support傳送binary data
但即使能support binary , JavaScript如何來處理這些data也是一個問題
另外如果有作多個connection的話 也是要client自己來maintain這些connections
(Multiplexing)
WebSocket Server端的軟體
Web::Hippie:AnyEvent
http://clkao.vox.com/library/post/hippie---getting-started.html
講者自己寫的package
講一下而已 大概沒一個小時就講完了

add prebuild lib in apk under mydroid

在mydroid build中
有個LOCAL_JNI_SHARED_LIBRARY可以指定自己的jni

但是這前提是這jni lib也是在某個LOCAL_MODULE中編出來的

如果想直接把這lib包進apk中
看了看build/core/package.mk

可以使用下面的密技:
$(shell cp $(wildcard $(LOCAL_PATH)/libs/armeabi/*.so) $(TARGET_OUT_INTERMEDIATE_LIBRARIES))

LOCAL_JNI_SHARED_LIBRARIES:= your_prebuild_lib