alibaba/QLExpress
QLExpress
QLExpress ist eine dynamische Skript-Engine und Ausdruckssprache für die Java-Plattform. Sie fungiert als Laufzeit-Ausdrucksauswerter und Business-Rule-Engine, die es Anwendungen ermöglicht, Skripte auszuführen und Geschäftslogik auszuwerten, ohne dass eine System-Neukompilierung erforderlich ist.
Die Engine zeichnet sich durch eine sichere Skript-Sandbox aus, die Sicherheitsrichtlinien via Class-Whitelisting und Ausführungs-Timeouts durchsetzt. Sie unterstützt hochpräzise Mathematik, um Rundungsfehler zu vermeiden, und bietet Unterstützung für Sprach-Aliase, um domänenspezifische Sprachen zu erstellen, die natürlicher Sprache ähneln. Zusätzliche Funktionen umfassen einen Makro-basierten Fragment-Replay-Mechanismus und die Möglichkeit, bestehende Java-Klassen durch das Injizieren neuer Member-Methoden zu erweitern, die nur innerhalb der Skriptumgebung zugänglich sind.
Das System deckt ein breites Spektrum an Funktionen ab, einschließlich Bytecode-basierter Kompilierung mit Skript-Caching, Auswertung abstrakter Syntaxbäume und dynamischer String-Interpolation. Es bietet zudem Observability durch knotenbasierte Ausführungsverfolgung für die Ursachenanalyse sowie Skript-Syntaxvalidierung und Unterstützung komplexer Datenstrukturen unter Verwendung von JSON-Syntax.
Features
- Business Rule Engines - Functions as a business rule engine allowing complex operational logic to be changed at runtime without recompilation.
- Expression Evaluators - Functions as a general-purpose engine for processing mathematical and logical expressions during runtime.
- Embeddable Scripting Engines - Provides an embeddable scripting engine for Java applications to support flexible logic updates and DSLs.
- Expression Parsing - Uses a formal grammar to decompose text into mathematical and logical operators for deterministic evaluation.
- Bytecode Compilation - Translates scripts into an internal binary format to improve execution speed and avoid repeated parsing.
- Dynamic Expression Languages - Serves as a dynamic expression language for the Java platform to evaluate business rules at runtime.
- Dynamic Script Execution - Evaluates expressions and runs scripts within an application to change business logic without requiring a full recompile.
- External Variable Mapping - Extracts required external variables and functions from scripts to prepare the necessary execution context.
- Expression Tree Evaluators - Implements a recursive visitor pattern to evaluate logical operations within a generated expression tree.
- Sandbox Permissions - Enforces security policies via class whitelisting and execution timeouts within a controlled scripting sandbox.
- Scripting Sandboxes - Restricts access to class fields and methods using configurable security policies like whitelists or isolation.
- Secure Sandboxing - Provides an execution environment that enforces security policies through class whitelisting and execution timeouts.
- Runtime Variable Mappings - Provides a mechanism to map script variables to external Java objects during the runtime execution phase.
- Scripted Function Definitions - Allows defining and invoking reusable named or anonymous functions within the scripting environment.
- Runtime Expression Evaluation - Calculates dynamic values and executes scripts on the fly using external variables and custom functions.
- Script Validators - Validates script syntax and security constraints before execution to prevent runtime errors and unauthorized access.
- Syntax Validation - Checks for syntax errors and enforces operator restrictions without executing the script to ensure correctness.
- Compiled Caches - Stores compiled expressions in memory or as serializable objects to eliminate redundant parsing overhead.
- Script Execution Timeouts - The project interrupts script execution after a specified duration to prevent infinite loops from consuming system resources.
- Runtime Method Injection - Adds new member methods to existing Java classes that remain accessible exclusively within the script environment.
- Complex Data Structure Support - Provides JSON-based syntax for defining maps, lists, and complex objects within scripts.
- Domain Specific Languages - Supports the creation of simplified, natural language syntax to allow non-technical users to write business logic.
- Dynamic Variable Injection - Supports nested dependencies by defining variables as expressions that depend on other variables.
- Language Alias Support - Allows assigning custom names to keywords and functions to make scripts read more like natural language.
- Macro-Based Fragment Replay - Encapsulates script fragments for reuse through a replay mechanism that shares the caller's scope.
- Macro Replay Mechanisms - Implements a macro-based fragment replay mechanism to encapsulate and reuse script segments.
- String Interpolation - Embeds expression results directly into strings using template syntax for flexible text generation.
- High Precision Mathematics - Uses high-precision decimal types for numbers that cannot be represented exactly by doubles to prevent rounding errors.
- Dynamic Class Extensions - Enables the extension of existing Java classes by injecting new member methods accessible only within the script environment.
- Method Logic Injection - Allows attaching new behaviors to existing Java classes at runtime via proxies accessible within scripts.
- Execution Tracing - Records intermediate values of every node during evaluation to provide a detailed tree for root cause analysis.
- Step-Level Tracing - Records the result of every single operation in the syntax tree to enable detailed debugging and root cause analysis.
