JAKARTA expression language API performance optimization and adjustment skills

Jakarta expression language (Jexl) is a dynamic script language for performing and evaluating expressions in Java applications.Optimization and tuning JEXL code is an important step to ensure that the performance of the application is efficient.This article will introduce the performance optimization and adjustment skills of some Jakarta expression language API, and provide relevant programming code and configuration description. 1. Use cache: When using Jexl parsing expression, you can consider creating an expression instance at runtime and cache it to avoid re -analysis of the expression each time.This can improve code execution efficiency.The following is an example code: JexlEngine jexl = new JexlBuilder().cache(512).create(); Expression expression = jexl.createExpression("your_expression"); JexlContext context = new MapContext(); ... Object result = expression.evaluate(context); In this example, we use Jexlbuilder to create a JexLengine instance, and use the cache method to specify the cache size.Then, we used the CreateexPression method to create an Expression instance and cached it.Finally, the expression expression is evaluated in a given context through the Evaluate method. 2. Avoid repeatedly compiling expressions in the cycle: if you use expressions in the cycle, avoid re -compiling expressions at each iteration.Instead, pre -compilation of expression can be compiled before the cycle and reused in the cycle.The following is an example code: JexlEngine jexl = new JexlBuilder().create(); JexlExpression expression = jexl.createExpression("your_expression"); JexlContext context = new MapContext(); ... for (...) { // Update context Object result = expression.evaluate(context); // Execute other operations } In this example, we use the CreateexPression method to compile the expression in advance and use it in a loop.This can avoid repeated compilation of performance losses. 3. Use the right context: Jexl uses JexlContext to provide context information for variables and methods.In terms of performance optimization, the use of suitable context can improve code execution efficiency.The default JexlContext implementation of MapContext is based on MAP, but if you have a more special context, you can consider using it.The following is an example code: JexlEngine jexl = new JexlBuilder().create(); Expression expression = jexl.createExpression("your_expression"); YourCustomContext context = new YourCustomContext(); ... Object result = expression.evaluate(context); In this example, we use YORCUSTOMCONTEX as the context to evaluate the expression.If you have some specific context needs, you can achieve your own context to improve performance. 4. Estimated and optimized expression: During the application development process, you can calculate and optimize expressions in advance to improve code performance.For example, calculate some fixed calculation steps in advance and save them into variables, and then use these variables in the expression.This can reduce the number of expressions of expression and improve code execution efficiency.The following is an example code: JexlEngine jexl = new JexlBuilder().create(); Expression expression = jexl.createExpression("your_expression"); JexlContext context = new MapContext(); ... // Calculate some values in advance Object value1 = calculateValue1(); Object value2 = calculateValue2(); ... // Set the context variable context.set("variable1", value1); context.set("variable2", value2); ... Object result = expression.evaluate(context); In this example, we calculate some values in advance, then save them into the context variables, and then use these variables in the expression.This can reduce the number of expressions of expression and improve code performance. Summarize: Optimizing and tuning Jakarta expression language API code is an important step to ensure the efficiency of code execution.By using cache, avoiding repeated compilation of expressions, using appropriate contexts and expected calculations and optimization expressions, the performance of the program can be improved.The above example code provides some specific implementation details, which can be adjusted and optimized according to actual needs.