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docs/execute-en.adoc

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+:toc:
+
+= Expression Execution
+
+This section describes the different ways to execute expressions in QLExpress4.
+
+== Use Map as the context
+
+- `execute(String, Map<String,Object>, QLOptions)`
+- Description: According to the method comments, use a `Map` as the context; the keys in the `Map` are the variable names used in the script, and the values are the corresponding variable values.
+- Typical scenario: Build a `Map` from external business data and pass it in so the script can access variables directly by name.
+
+[source,java,indent=0]
+----
+        Express4Runner express4Runner = new Express4Runner(InitOptions.DEFAULT_OPTIONS);
+        Map<String, Object> context = new HashMap<>();
+        context.put("a", 1);
+        context.put("b", 2);
+        context.put("c", 3);
+        Object result = express4Runner.execute("a + b * c", context, QLOptions.DEFAULT_OPTIONS).getResult();
+        assertEquals(7, result);
+----
+
+== Use object fields as the context
+
+- `execute(String, Object, QLOptions)`
+- Description: Use a plain Java object as the context; variable names in the script correspond to the object's field names (or accessible getters).
+- Typical scenario: When you already have a DTO/POJO that carries the context data, pass the object directly so the script can read its fields.
+
+// Note: This references the test code for execution with an object context.
+[source,java,indent=0]
+----
+        MyObj myObj = new MyObj();
+        myObj.a = 1;
+        myObj.b = "test";
+        
+        Express4Runner express4Runner = new Express4Runner(InitOptions.DEFAULT_OPTIONS);
+        Object result = express4Runner.execute("a+b", myObj, QLOptions.DEFAULT_OPTIONS).getResult();
+        assertEquals("1test", result);
+----
+
+== Use a set of aliased objects
+
+- `executeWithAliasObjects(String, QLOptions, Object...)`
+- Description: Pass objects annotated with `@QLAlias`; the annotation value becomes the variable name in the context. Objects without the annotation are ignored.
+- Typical scenario: Expose object properties/methods with Chinese (or domain-specific) aliases so rule authors can write scripts more intuitively.
+
+[source,java,indent=0]
+----
+        Order order = new Order();
+        order.setOrderNum("OR123455");
+        order.setAmount(100);
+        
+        User user = new User();
+        user.setName("jack");
+        user.setVip(true);
+        
+        // Calculate the Final Order Amount
+        Express4Runner express4Runner =
+            new Express4Runner(InitOptions.builder().securityStrategy(QLSecurityStrategy.open()).build());
+        Number result = (Number)express4Runner
+            .executeWithAliasObjects("用户.是vip? 订单.金额 * 0.8 : 订单.金额", QLOptions.DEFAULT_OPTIONS, order, user)
+            .getResult();
+        assertEquals(80, result.intValue());
+----
+
+== Use a custom `ExpressContext`
+
+- `execute(String, ExpressContext, QLOptions)`
+- Description: This overload allows passing a custom context that implements `ExpressContext` (for example, a dynamic variable context). The other `execute` overloads ultimately delegate to this method.
+- Typical scenario: When you need on-demand, by-name evaluation of variable values, read/write isolation, or integration with external storage, a custom context is the most flexible choice.
+
+[source,java,indent=0]
+----
+        Express4Runner express4Runner = new Express4Runner(InitOptions.DEFAULT_OPTIONS);
+        
+        Map<String, Object> staticContext = new HashMap<>();
+        staticContext.put("语文", 88);
+        staticContext.put("数学", 99);
+        staticContext.put("英语", 95);
+        
+        QLOptions defaultOptions = QLOptions.DEFAULT_OPTIONS;
+        DynamicVariableContext dynamicContext =
+            new DynamicVariableContext(express4Runner, staticContext, defaultOptions);
+        dynamicContext.put("平均成绩", "(语文+数学+英语)/3.0");
+        dynamicContext.put("是否优秀", "平均成绩>90");
+        
+        // dynamic var
+        assertTrue((Boolean)express4Runner.execute("是否优秀", dynamicContext, defaultOptions).getResult());
+        assertEquals(94,
+            ((Number)express4Runner.execute("平均成绩", dynamicContext, defaultOptions).getResult()).intValue());
+        // static var
+        assertEquals(187,
+            ((Number)express4Runner.execute("语文+数学", dynamicContext, defaultOptions).getResult()).intValue());
+----