Package net.i2p

Class I2PAppContext

java.lang.Object
net.i2p.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 Details

    • _globalAppContext

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

    • _overrideProps

      protected final I2PProperties _overrideProps

    • _sessionKeyManager

      protected SessionKeyManager _sessionKeyManager

    • _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 Details

    • 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 Details

    • 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

    • getLibDir

      public File getLibDir()
      This is the library dir, which is usually $I2P/lib. It contains all the jars (i.e. the classpath). Most applications will not need this, and must treat this directory as read-only.
      Returns:
      dir constant for the life of the context
      Since:
      0.9.52

    • 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

    • hmac256

      public HMAC256Generator hmac256()
      Un-deprecated in 0.9.38

    • 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

    • removeShutdownTask

      public void removeShutdownTask(Runnable task)
      Since:
      0.9.53

    • 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:
      0.9.47