Architecture

ActivityContext Build Process: An In-Depth Analysis

ActivityContext, the heart of an Aspectran application, is created through a systematic process by the ActivityContextBuilder. This build process is largely divided into four stages: Configuration, Parsing, Creation, and Initialization, and the entire process is led by the com.aspectran.core.context.builder.HybridActivityContextBuilder class.

1. Builder Creation & Configuration

Everything starts with creating an instance of ActivityContextBuilder. After the builder is created, the developer provides the core information needed to configure the context through various setter methods.

  • setBasePath(String basePath): Specifies the root directory of the application. It serves as the base point for relative paths.
  • setContextRules(String[] contextRules): Passes the paths of Aspectran’s core configuration files (in XML or APON format) as an array. This allows for managing multiple configuration files like modules.
  • setBasePackages(String... basePackages): Specifies the packages to be used for annotation-based component scanning. The builder finds annotations like @Component, @Bean, and @Aspect under these packages and automatically generates rules.
  • setActiveProfiles(String... activeProfiles): Specifies the application’s execution environment profiles (e.g., dev, prod). Only configurations that match the specified profiles are activated.
  • setResourceLocations(String... resourceLocations): Allows for dynamically adding resource paths to be included in the classpath.
  • setAponWriter(AponWriter aponWriter): Used for debugging by outputting the parsed rules in APON format.

2. Build & Parsing

Once the configuration is complete, the build() method is called to start the actual build process. The substantive work of this stage is handled by com.aspectran.core.context.rule.parser.HybridActivityContextRuleParser.

  1. Parser Initialization: HybridActivityContextRuleParser internally creates a core helper object called RuleParsingContext. RuleParsingContext temporarily stores all parsed rules (*Rule objects), sets up relationships between rules, and is ultimately responsible for configuring the registries.

  2. Rule Parsing: The parser performs its work based on the configured contextRules and basePackages.
    • File-based Parsing: It iterates through the configuration files specified in contextRules and parses their content using XmlActivityContextParser or AponActivityContextParser depending on the file extension. The parsed result is converted into a tree of rule objects defined in the com.aspectran.core.context.rule package, such as AspectRule, BeanRule, and TransletRule.
    • Annotation-based Parsing: It scans the package paths specified in basePackages to find classes annotated with @Component, @Bean, @Aspect, etc. AnnotatedClassParser analyzes these classes and creates equivalent BeanRule and AspectRule objects.
  3. Rule Registration: All created *Rule objects are added to the appropriate internal collections by RuleParsingContext. At this point, the rules are only loaded into memory; no actual instances have been created yet.

3. Context Creation

This is the stage where the actual ActivityContext instance is created based on the parsed rules.

  1. DefaultActivityContext Creation: The createActivityContext() method creates an instance of com.aspectran.core.context.DefaultActivityContext.

  2. Registry Injection: RuleParsingContext categorizes all the temporarily stored rules and creates final registry objects like AspectRuleRegistry, BeanRuleRegistry, and TransletRuleRegistry, which are then injected into DefaultActivityContext.

  3. Validation: The validity of the rules is checked to ensure that the context can operate correctly.

    • BeanReferenceInspector: It tracks all relationships that reference other beans from @Autowired or configuration files and checks for errors such as referencing a non-existent bean or circular references.
    • AspectRuleValidator: It verifies whether the AOP rules are valid, for example, whether the bean and method specified by the advice actually exist.

4. Initialization & Completion

This is the final stage of activating the created context so that it can be used by the application.

  1. ActivityContext.initialize() Call: When this method is called, the initialization of the context begins.
    • Singleton Bean Instantiation: All singleton-scoped beans registered in the BeanRegistry are actually instantiated. During this process, constructor injection occurs, and dependency injection for fields and methods annotated with @Autowired is completed.
    • Initialization Callback Execution: The initialization methods of beans that are annotated with @Initialize or implement the InitializableBean interface are called.

  2. Auto-Reloading Activation (Optional): If the autoReload setting is enabled, ContextReloadingTimer is started. This timer monitors the configuration files for changes at a specified interval (scanInterval), and if a change is detected, it calls serviceLifeCycle.restart() to perform the build process described above from the beginning. This allows for dynamically reflecting configuration changes without restarting the application.

  3. Context Return: After all processes are successfully completed, the fully activated ActivityContext object is provided as the final return value of the build() method.