Package org.mozilla.javascript.commonjs.module.provider

Class CachingModuleScriptProviderBase

java.lang.Object
org.mozilla.javascript.commonjs.module.provider.CachingModuleScriptProviderBase
All Implemented Interfaces:
Serializable, ModuleScriptProvider
Direct Known Subclasses:
SoftCachingModuleScriptProvider, StrongCachingModuleScriptProvider
public abstract class CachingModuleScriptProviderBase extends Object implements ModuleScriptProvider, Serializable
Abstract base class that implements caching of loaded module scripts. It uses a ModuleSourceProvider to obtain the source text of the scripts. It supports a cache revalidation mechanism based on validator objects returned from the ModuleSourceProvider. Instances of this class and its subclasses are thread safe (and written to perform decently under concurrent access).
Version:
$Id: CachingModuleScriptProviderBase.java,v 1.3 2011/04/07 20:26:12 hannes%helma.at Exp $
See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      See Also:

    • loadConcurrencyLevel

      private static final int loadConcurrencyLevel

    • loadLockShift

      private static final int loadLockShift

    • loadLockMask

      private static final int loadLockMask

    • loadLockCount

      private static final int loadLockCount

    • loadLocks

      private final Object[] loadLocks

    • moduleSourceProvider

      private final ModuleSourceProvider moduleSourceProvider

  • Constructor Details

    • CachingModuleScriptProviderBase

      protected CachingModuleScriptProviderBase(ModuleSourceProvider moduleSourceProvider)
      Creates a new module script provider with the specified source.
      Parameters:
      moduleSourceProvider - provider for modules' source code

  • Method Details

    • getModuleScript

      public ModuleScript getModuleScript(Context cx, String moduleId, URI moduleUri, URI baseUri, Scriptable paths) throws Exception
      Description copied from interface: ModuleScriptProvider
      Returns a module script. It should attempt to load the module script if it is not already available to it, or return an already loaded module script instance if it is available to it.
      Specified by:
      getModuleScript in interface ModuleScriptProvider
      Parameters:
      cx - current context. Can be used to compile module scripts.
      moduleId - the ID of the module. An implementation must only accept an absolute ID, starting with a term.
      moduleUri - the URI of the module. If this is not null, resolution of moduleId is bypassed and the script is directly loaded from moduleUri
      baseUri - the module path base URI from which moduleUri was derived.
      paths - the value of the require() function's "paths" attribute. If the require() function is sandboxed, it will be null, otherwise it will be a JavaScript Array object. It is up to the provider implementation whether and how it wants to honor the contents of the array.
      Returns:
      a module script representing the compiled code of the module. Null should be returned if the script could not found.
      Throws:
      Exception - if there was an unrecoverable problem obtaining the script

    • putLoadedModule

      protected abstract void putLoadedModule(String moduleId, ModuleScript moduleScript, Object validator)
      Store a loaded module script for later retrieval using getLoadedModule(String).
      Parameters:
      moduleId - the ID of the module
      moduleScript - the module script
      validator - the validator for the module's source text entity

    • getLoadedModule

      protected abstract CachingModuleScriptProviderBase.CachedModuleScript getLoadedModule(String moduleId)
      Retrieves an already loaded moduleScript stored using putLoadedModule(String, ModuleScript, Object).
      Parameters:
      moduleId - the ID of the module
      Returns:
      a cached module script, or null if the module is not loaded.

    • getValidator

      private static Object getValidator(CachingModuleScriptProviderBase.CachedModuleScript cachedModule)

    • equal

      private static boolean equal(Object o1, Object o2)

    • getConcurrencyLevel

      protected static int getConcurrencyLevel()
      Returns the internal concurrency level utilized by caches in this JVM.
      Returns:
      the internal concurrency level utilized by caches in this JVM.