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org.eclipse.core.runtime.spi

Class RegistryStrategy

    • Constructor Detail

      • RegistryStrategy

        public RegistryStrategy(File[] storageDirs,
                                boolean[] cacheReadOnly)
        Constructor for this default registry strategy.

        The strategy sequentially checks the array of storage directories to discover the location of the registry cache formed by previous invocations of the extension registry. Once found, the location is used to store registry cache. If this value is null then caching of the registry content is disabled.

        The cache read-only array is an array the same length as the storage directory array. It contains boolean values indicating whether or not each storage directory is read-only. If the value at an index is true then the location at the corresponding index in the storage directories array is read-only; if false then the cache location is read-write. The array can be null if the storageDirs parameter is null.

        Parameters:
        storageDirs - array of file system directories, or null
        cacheReadOnly - array of read only attributes, or null
    • Method Detail

      • getLocationsLength

        public final int getLocationsLength()
        Returns the number of possible cache locations for this registry.
        Returns:
        number of possible cache locations for this registry
      • getStorage

        public final File getStorage(int index)
        Returns the possible registry cache location identified by the index.
        Parameters:
        index - index of the possible registry location
        Returns:
        potential registry cache location
      • isCacheReadOnly

        public final boolean isCacheReadOnly(int index)
        Returns the read-only status of the registry cache location.
        Parameters:
        index - the index of the possible registry location
        Returns:
        true if the location is read only and false if the location is read/write
      • log

        public void log(IStatus status)
        Override this method to provide customized logging functionality to the registry. The method adds a log entry based on the supplied status.

        This method writes a message to System.out in the following format:

         [Error|Warning|Log]: Main error message
         [Error|Warning|Log]: Child error message 1
                ...
         [Error|Warning|Log]: Child error message N
         

        Parameters:
        status - the status to log
      • translate

        public String translate(String key,
                                ResourceBundle resources)
        Translates key using the supplied resource bundle. The resource bundle is optional and might be null.

        The default translation routine assumes that keys are prefixed with '%'. If no resource bundle is present, the key itself (without leading '%') is returned. There is no decoding for the leading '%%'.

        Parameters:
        key - message key to be translated
        resources - resource bundle, or null
        Returns:
        the translated string, must not be null
      • onStart

        public void onStart(IExtensionRegistry registry)
        Override this method to provide additional processing performed when the registry is created and started. Overrides should call super.onStart() at the beginning of the processing.

        NOTE: Avoid placing duplicate functionality in this method and onStart(IExtensionRegistry, boolean) as both methods will be called on the registry startup.

        Parameters:
        registry - the extension registry being started
      • onStart

        public void onStart(IExtensionRegistry registry,
                            boolean loadedFromCache)
        Override this method to provide additional processing performed when the registry is created and started. Overrides should call super.onStart() at the beginning of the processing.
        Parameters:
        registry - the extension registry being started
        loadedFromCache - true is registry contents was loaded from cache when the registry was created
        Since:
        3.4
      • onStop

        public void onStop(IExtensionRegistry registry)
        Override this method to provide additional processing to be performed just before the registry is stopped. Overrides should call super.onStop() at the end of the processing.
        Parameters:
        registry - the extension registry being stopped
      • createExecutableExtension

        public Object createExecutableExtension(RegistryContributor contributor,
                                                String className,
                                                String overridenContributorName)
                                         throws CoreException
        Creates an executable extension. Override this method to supply an alternative processing for the creation of executable extensions.

        This method receives the contributor of the executable extension and, possibly, an optional contributor name if specified by the executable extension. The overridden contributor name might be null.

        In this implementation registry attempts to instantiate the class specified via the class name (must not be null) using standard Java reflection mechanism. This method assumes that such class has a default constructor with no arguments.

        Parameters:
        contributor - the contributor of this executable extension
        className - the name of the class to be instantiated
        overridenContributorName - the contributor to be used, or null if not specified
        Returns:
        the object created, or null
        Throws:
        CoreException - if there was a problem creating the executable extension
        See Also:
        IConfigurationElement.createExecutableExtension(String), IExecutableExtension
      • scheduleChangeEvent

        public void scheduleChangeEvent(Object[] listeners,
                                        Map deltas,
                                        Object registry)
        Override this method to customize scheduling of an extension registry event. Note that this method must make the following call to actually process the event:

        
                RegistryStrategy.processChangeEvent(listeners, deltas, registry);
         

        In the default implementation, the method registry events are executed in a queue on a separate thread (i.e. asynchronously, sequentially).

        Parameters:
        listeners - the list of active listeners (thread safe); may not be null
        deltas - the registry deltas (thread safe); may not be null
        registry - the extension registry (NOT thread safe); may not be null
      • processChangeEvent

        public static final IStatus processChangeEvent(Object[] listeners,
                                                       Map deltas,
                                                       Object registry)
        This method performs actual processing of the registry change event. It should only be used by overrides of the RegistryStrategy.scheduleChangeEvent. It will return null if an unexpected registry type was encountered.
        Parameters:
        listeners - the list of active listeners; may not be null
        deltas - the extension registry deltas; may not be null
        registry - the extension registry; may not be null
        Returns:
        status of the operation or null
      • debug

        public boolean debug()
        Override this method to specify debug requirements to the registry. In the default implementation this method returns false indicating that debug functionality is turned off.

        Note that in a general case the extension registry plug-in doesn't depend on OSGI and therefore cannot use Eclipse .options files to discover debug options.

        Returns:
        true if debug logging and validation should be performed and false otherwise
      • debugRegistryEvents

        public boolean debugRegistryEvents()
        Override this method to specify debug requirements for the registry event processing. In the default implementation this method returns false indicating that debug of the registry events is turned off.

        Note that in a general case the extension registry plug-in doesn't depend on OSGI and therefore cannot use Eclipse .options files to discover debug options.

        Returns:
        true if debug logging and validation of the registry events should be performed and false otherwise
      • cacheUse

        public boolean cacheUse()
        Specifies if the extension registry should use cache to store registry data between invocations.

        The default implementation enables caching returning true.

        Returns:
        true if the cache should be used and false otherwise
      • cacheLazyLoading

        public boolean cacheLazyLoading()
        Specifies if lazy cache loading is used.

        The default implementation specifies that lazy cache loading is going to be used and therefore returns true.

        Returns:
        true if lazy cache loading is used and false otherwise
      • getContainerTimestamp

        public long getContainerTimestamp()
        This method is called as a part of the registry cache validation. The cache is valid on the registry startup if the pair {container time stamp, contributors time stamp} supplied by the registry strategy is the same as the {container time stamp, contributors time stamp} stored in the registry cache. The goal of the validation is to be able to catch modifications made to the original data contributed into the registry and not reflected in the registry cache.

        The method produces a number that corresponds to the current state of the data stored by the container. Increment the stamp if the data stored in the container has been updated so that the data cached by the registry is no longer valid. For instance, in Eclipse addition or removal of a bundle results in the number returned by this method being incremented. As a result, if a bundle that contributed plugin.xml into the extension registry was modified, the state doesn't match the state stored in the registry cache. In this case the cache content becomes invalid and the registry needs to be re-created from the original data.

        Generally, treat this number as a hash code for the data stored in the registry. It stays the same as long as the registry content is not changing. It becomes a different number as the registry content gets modified.

        Return 0 to indicate that state verification is not required.

        Returns:
        number indicating state of the application data
      • getContributionsTimestamp

        public long getContributionsTimestamp()
        This method is called as a part of the registry cache validation. The method calculates a number describing the time when the originating contributions (i.e., plugin.xml files in case of the Eclipse registry) were last modified.

        The value returned by the method is compared with the timestamp tracked by the registry. If contributions changed since they have been added to the registry (i.e., plugin.xml file was modified since the last run), the value of the getContributionsTimestamp() will change and no longer will be the same as the value tracked by the registry. In this case the cache is considered to be invalid and the registry is going to be re-populated form scratch.

        (The word "timestamp" is used very loosely here. In this context, "timestamp" is more likely to be a hash value aggregating a number of actual timestamps from the contributions.)

        This method may return 0 to indicate that no time stamp verification is required.

        Returns:
        a value corresponding to the last modification time of contributions contained in the registry
      • translate

        public String[] translate(String[] nonTranslated,
                                  IContributor contributor,
                                  String locale)
        Translates array of keys supplied by the contributor to the requested locale.

        This method is intended to be overridden by specialized registry strategies that know translation conventions for the contributors, for instance, the agreed upon locations of the translated keys for bundle contributors. The base implementation simply returns the array of non-translated keys.

        This method is only used if multi-language support is enabled.

        Parameters:
        nonTranslated - message keys to be translated
        contributor - the contributor of the keys to be translated
        locale - the requested locale for the keys
        Returns:
        the arrays of translated strings
        Since:
        org.eclipse.equinox.registry 3.5
        See Also:
        IExtensionRegistry.isMultiLanguage()
      • getLocale

        public String getLocale()
        Returns the current locale for the extension registry with enabled multi-language support.

        The default implementation assumes that there is a single system wide locale, equivalent to Locale.getDefault().

        The result of this method should not be retained or passed to other threads. The current locale can change any time and may be different for each thread.

        This method can be overridden by subclasses that wish to provide a way to change the default locale.

        This method is only used if multi-language support is enabled.

        Returns:
        the default locale
        Since:
        org.eclipse.equinox.registry 3.5
        See Also:
        IExtensionRegistry.isMultiLanguage()


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