Package net.i2p

Class I2PAppContext

  • Direct Known Subclasses:
    RouterContext
    public class I2PAppContext
extends Object

    Provide a base scope for accessing singletons that I2P exposes. Rather than using the traditional singleton, where any component can access the component in question directly, all of those I2P related singletons are exposed through a particular I2PAppContext. This helps not only with understanding their use and the components I2P exposes, but it also allows multiple isolated environments to operate concurrently within the same JVM - particularly useful for stubbing out implementations of the rooted components and simulating the software's interaction between multiple instances.

    As a simplification, there is also a global context - if some component needs access to one of the singletons but doesn't have its own context from which to root itself, it binds to the I2PAppContext's globalAppContext(), which is the first context that was created within the JVM, or a new one if no context existed already. This functionality is often used within the I2P core for logging - e.g. 
         private static final Log _log = new Log(someClass.class);
    It is for this reason that applications that care about working with multiple contexts should build their own context as soon as possible (within the main(..)) so that any referenced components will latch on to that context instead of instantiating a new one. However, there are situations in which both can be relevant.

    • Field Detail

      • _globalAppContext

        protected static volatile I2PAppContext _globalAppContext
        the context that components without explicit root are bound

      • _clock

        protected Clock _clock

      • _keyRing

        protected KeyRing _keyRing

      • _sessionKeyManagerInitialized

        protected volatile boolean _sessionKeyManagerInitialized

      • _clockInitialized

        protected volatile boolean _clockInitialized

      • _keyRingInitialized

        protected volatile boolean _keyRingInitialized

      • _shutdownTasks

        protected final Set<Runnable> _shutdownTasks

    • Constructor Detail

      • I2PAppContext

        public I2PAppContext()
        Create a brand new context. WARNING: In almost all cases, you should use getGlobalContext() instead, to avoid creating additional contexts, which may spawn numerous additional resources and threads, and may be the cause of logging problems or hard-to-isolate bugs.

      • I2PAppContext

        public I2PAppContext​(Properties envProps)
        Create a brand new context. WARNING: In almost all cases, you should use getGlobalContext() instead, to avoid creating additional contexts, which may spawn numerous additional resources and threads, and may be the cause of logging problems or hard-to-isolate bugs.

      • I2PAppContext

        protected I2PAppContext​(boolean doInit,
                        Properties envProps)
        Create a brand new context. WARNING: In almost all cases, you should use getGlobalContext() instead, to avoid creating additional contexts, which may spawn numerous additional resources and threads, and may be the cause of logging problems or hard-to-isolate bugs. NOT a public API, for use by RouterContext only, NOT for external use.
        Parameters:
        doInit - should this context be used as the global one (if necessary)? Will only apply if there is no global context now.
        Since:
        protected since 0.9.33, NOT for external use

    • Method Detail

      • getGlobalContext

        public static I2PAppContext getGlobalContext()
        Pull the default context, creating a new one if necessary, else using the first one created. Warning - do not save the returned value, or the value of any methods below, in a static field, or you will get the old context if a new router is started in the same JVM after the first is shut down, e.g. on Android.

      • setGlobalContext

        protected static boolean setGlobalContext​(I2PAppContext ctx)
        Sets the default context, unless there is one already. NOT a public API, for use by RouterContext only, NOT for external use.
        Parameters:
        ctx - context constructed with doInit = false
        Returns:
        success (false if previously set)
        Since:
        0.9.33

      • getCurrentContext

        public static I2PAppContext getCurrentContext()
        Pull the default context, WITHOUT creating a new one. Use this in static methods used early in router initialization, where creating a context messes things up.
        Returns:
        context or null
        Since:
        0.8.2

      • getBaseDir

        public File getBaseDir()
        This is the installation dir, often referred to as $I2P. Applilcations should consider this directory read-only and never attempt to write to it. It may actually be read-only on a multi-user installation. The config files in this directory are templates for user installations and should not be accessed by applications. The only thing that may be useful in here is the lib/ dir containing the .jars.
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • getConfigDir

        public File getConfigDir()
        The base dir for config files. Applications may use this to access router configuration files if necessary. Usually ~/.i2p on Linux and %APPDIR%\I2P on Windows. In installations originally installed with 0.7.5 or earlier, and in "portable" installations, this will be the same as the base dir.
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • getRouterDir

        public File getRouterDir()
        Where the router keeps its files. Applications should not use this. The same as the config dir for now.
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • getPIDDir

        public File getPIDDir()
        Where router.ping goes. Applications should not use this. The same as the router dir by default as of 0.8.12 Was the same as the system temp dir prior to that. Which was a problem for multi-user installations.
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • getLogDir

        public File getLogDir()
        Where the router keeps its log directory. Applications should not use this. The same as the config dir for now. (i.e. ~/.i2p, NOT ~/.i2p/logs)
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • getAppDir

        public File getAppDir()
        Where applications may store data. The same as the config dir for now, but may change in the future. Apps should be careful not to overwrite router files.
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • getTempDir

        public File getTempDir()
        Where anybody may store temporary data. This is a directory created in the system temp dir on the first call in this context, and is deleted on JVM exit. Applications should create their own directory inside this directory to avoid collisions with other apps.
        Returns:
        dir constant for the life of the context
        Since:
        0.7.6

      • deleteTempDir

        public void deleteTempDir()
        don't rely on deleteOnExit()

      • getProperty

        public String getProperty​(String propName)
        Access the configuration attributes of this context, using properties provided during the context construction, or falling back on System.getProperty if no properties were provided during construction (or the specified prop wasn't included).

      • getProperty

        public String getProperty​(String propName,
                          String defaultValue)
        Access the configuration attributes of this context, using properties provided during the context construction, or falling back on System.getProperty if no properties were provided during construction (or the specified prop wasn't included).

      • getProperty

        public int getProperty​(String propName,
                       int defaultVal)
        Return an int with an int default

      • getProperty

        public long getProperty​(String propName,
                        long defaultVal)
        Return a long with a long default
        Since:
        0.9.4

      • getProperty

        public boolean getProperty​(String propName,
                           boolean defaultVal)
        Return a boolean with a boolean default
        Since:
        0.7.12

      • getBooleanProperty

        public boolean getBooleanProperty​(String propName)
        Default false
        Since:
        0.7.12

      • getBooleanPropertyDefaultTrue

        public boolean getBooleanPropertyDefaultTrue​(String propName)
        Since:
        0.7.12

      • getPropertyNames

        public Set<String> getPropertyNames()
        Access the configuration attributes of this context, listing the properties provided during the context construction, as well as the ones included in System.getProperties. WARNING - not overridden in RouterContext, doesn't contain router config settings, use getProperties() instead.
        Returns:
        set of Strings containing the names of defined system properties

      • getProperties

        public Properties getProperties()
        Access the configuration attributes of this context, listing the properties provided during the context construction, as well as the ones included in System.getProperties.
        Returns:
        new Properties with system and context properties
        Since:
        0.8.4

      • addPropertyCallback

        public void addPropertyCallback​(I2PProperties.I2PPropertyCallback callback)
        Add a callback, which will fire upon changes in the property given in the specific callback. Unimplemented in I2PAppContext: this only makes sense in a router context.
        Parameters:
        callback - The implementation of the callback.

      • statManager

        public StatManager statManager()
        The statistics component with which we can track various events over time.

      • sessionKeyManager

        public SessionKeyManager sessionKeyManager()
        The session key manager which coordinates the sessionKey / sessionTag data. This component allows transparent operation of the ElGamal/AES+SessionTag algorithm, and contains all of the session tags for one particular application. This is deprecated for client use, it should be used only by the router as its own key manager. Not that clients are doing end-to-end crypto anyway. For client crypto within the router, use RouterContext.clientManager.getClientSessionKeyManager(dest) As of 0.9.15, this returns a dummy SessionKeyManager in I2PAppContext. The dummy SKM does NOT handle session tags. Overridden in RouterContext to return the full TransientSessionKeyManager.

      • initializeSessionKeyManager

        protected void initializeSessionKeyManager()

      • namingService

        public NamingService namingService()
        Pull up the naming service used in this context. The naming service itself works by querying the context's properties, so those props should be specified to customize the naming service exposed.

      • elGamalEngine

        public ElGamalEngine elGamalEngine()
        This is the ElGamal engine used within this context. While it doesn't really have anything substantial that is context specific (the algorithm just does the algorithm), it does transparently use the context for logging its performance and activity. In addition, the engine can be swapped with the context's properties (though only someone really crazy should mess with it ;)

      • aes

        public AESEngine aes()
        Ok, I'll admit it. there is no good reason for having a context specific AES engine. We dont really keep stats on it, since its just too fast to matter. Though for the crazy people out there, we do expose a way to disable it.

      • logManager

        public LogManager logManager()
        Query the log manager for this context, which may in turn have its own set of configuration settings (loaded from the context's properties). Each context's logManager keeps its own isolated set of Log instances with their own log levels, output locations, and rotation configuration.

      • setLogManager

        public void setLogManager​(LogManager logManager)
        Overwrites the LogManager instance to be used by the router. This should only be called after the Router is instantiated but before it is started. Calling this at any other time can have unpredictable side effects.
        Since:
        0.9.41

      • sha

        public SHA256Generator sha()
        Our SHA256 instance (see the hmac discussion for why its context specific)

      • dsa

        public DSAEngine dsa()
        Our DSA engine (see HMAC and SHA above)

      • keyGenerator

        public KeyGenerator keyGenerator()
        Component to generate ElGamal, DSA, and Session keys. For why it is in the appContext, see the DSA, HMAC, and SHA comments above.

      • clock

        public Clock clock()
        The context's synchronized clock, which is kept context specific only to enable simulators to play with clock skew among different instances.

      • initializeClock

        protected void initializeClock()

      • routingKeyGenerator

        public RoutingKeyGenerator routingKeyGenerator()
        Determine how much do we want to mess with the keys to turn them into something we can route. This is context specific because we may want to test out how things react when peers don't agree on how to skew. As of 0.9.16, returns null in I2PAppContext. You must be in RouterContext to get a generator.
        Returns:
        null always

      • keyRing

        public KeyRing keyRing()
        Basic hash map

      • initializeKeyRing

        protected void initializeKeyRing()

      • random

        public RandomSource random()
        [insert snarky comment here]

      • addShutdownTask

        public void addShutdownTask​(Runnable task)
        WARNING - Shutdown tasks are not executed in an I2PAppContext. You must be in a RouterContext for the tasks to be executed at shutdown. This method moved from Router in 0.7.1 so that clients may use it without depending on router.jar.
        Since:
        0.7.1

      • getShutdownTasks

        public Set<Runnable> getShutdownTasks()
        Returns:
        an unmodifiable Set
        Since:
        0.7.1

      • isRouterContext

        public boolean isRouterContext()
        Use this instead of context instanceof RouterContext
        Since:
        0.7.9

      • internalClientManager

        public InternalClientManager internalClientManager()
        Use this to connect to the router in the same JVM.
        Returns:
        always null in I2PAppContext, the client manager if in RouterContext
        Since:
        0.8.3

      • hasWrapper

        public boolean hasWrapper()
        Is the wrapper present?
        Since:
        0.8.8

      • portMapper

        public PortMapper portMapper()
        Basic mapping from service names to ports
        Since:
        0.8.12

      • simpleScheduler

        @Deprecated
public SimpleScheduler simpleScheduler()
        Deprecated.
        in 0.9.20, use simpleTimer2()
        Use instead of SimpleScheduler.getInstance()
        Since:
        0.9 to replace static instance in the class

      • simpleTimer

        @Deprecated
public SimpleTimer simpleTimer()
        Deprecated.
        use SimpleTimer2
        Use instead of SimpleTimer.getInstance()
        Since:
        0.9 to replace static instance in the class

      • simpleTimer2

        public SimpleTimer2 simpleTimer2()
        Use instead of SimpleTimer2.getInstance()
        Since:
        0.9 to replace static instance in the class

      • clientAppManager

        public ClientAppManager clientAppManager()
        As of 0.9.30, returns non-null in I2PAppContext, null in RouterContext. Prior to that, returned null always. Overridden in RouterContext to return the RouterAppManager.
        Returns:
        As of 0.9.30, returns non-null in I2PAppContext, null in RouterContext
        Since:
        0.9.11, in RouterContext since 0.9.4

      • getEstimatedDowntime

        public long getEstimatedDowntime()
        How long this router was down before it started, or 0 if unknown. This may be used for a determination of whether to regenerate keys, for example. We use the timestamp of the previous ping file left behind on crash, as set by isOnlyRouterRunning(), if present. Otherwise, the last STOPPED entry in the event log. May take a while to run the first time, if it has to go through the event log. Once called, the result is cached.
        Returns:
        0 always in app context
        Since:
        0.0.47