Introduction to 'Contracts for Java' framework in the Java class library

Java Contracts is a framework for achieving design contracts in the Java program.The design contract is a kind of agreement, which contains a set of front conditions, rear conditions, and classes that must be complied with during the method call.Using a design contract, you can clarify the relationship between the input and output of the method, and help developers understand and maintain the code easier. Contracts for Java framework provides a set of annotations and APIs to define and apply design contracts in code.It allows developers to specify the front conditions on the method signature and specify the rear conditions in the method body.These contract conditions may include non -air inspections, scope inspections, abnormal conditions, and return value constraints of parameters.By defining these conditions in the code clearly, the readability, maintenance and reliability of the code can be improved. Here are some examples of using Contracts for Java framework: 1. Pre -conditions: @Requires("value >= 0") public void setValue(int value) { // method body } In this example, through the @Requires annotation, the front conditions of the method SetValue specify that the Value must be greater than or equal to 0.In the method body, developers can assume that the front conditions are met with confidence. 2. Rear conditions: @Ensures("result > 0") public int calculateSquare(int value) { int result = value * value; return result; } In this example, the rear condition of the method of Calculatersquare using the @ENSURES annotation specifies that the return value must be greater than 0.By clearing this rear condition, developers can verify correctness of the return value of the method. 3. Abnormal conditions: @Throws(RuntimeException.class) public void performOperation() { // method body } In the above example, the @throws annotation specifies the method Performoperation may throw Runtimeexception anomaly.In this way, the recipient of the method can understand the risk of calling the method and prepare for abnormal processing. The use of the Contracts for Java framework can help developers better consider the front conditions, rear conditions, and abnormal conditions of the method call during the encoding process, thereby improving the quality and reliability of the code.