CHE CORE :: Commons :: Annotations framework in the java class library (in-design analysis of the check :: commands :: Annotation in java class libraries))
CHE CORE :: Commons :: Annotations framework in the java class library
introduction:
Che Core :: Commons :: Annotations framework is an important annotation framework in the Java class library.It provides a simple and flexible way to use annotations in the Java code.This article will conduct in -depth analysis of the framework, including its basic use, functional characteristics and common cases, and provide some Java code examples to help readers better understand and apply the framework.
1 Introduction
Che Core :: Commons :: Annotations framework is an open source Java annotation framework, which aims to simplify the process of developers' use of annotations.It provides some basic annotations that allow developers to achieve some specific functions by adding annotations to the code.
2. Basic use
The basic use of che.Developers only need to introduce the corresponding annotations in the Java code and apply the annotation to the right place.
For example, using @DepRecated annotation indicates that a certain method or class is outdated:
@Deprecated
public class OldClass {
// The implementation of the class ...
}
@Deprecated
public void oldMethod() {
// The implementation of the method ...
}
3. Functional characteristics
Chens :: Commons :: Annotations framework provides some functional characteristics, so that developers can use annotations more flexibly.
3.1 Custom annotation
Developers can customize their own annotations based on the annotations provided by the CHE CORE :: Commons :: Annotations framework.In this way, developers can define suitable annotations and use them in the code according to the project needs.
For example, define a customized annotation @Myannotation:
import org.eclipse.che.api.core.annotations.Nullable;
public @interface MyAnnotation {
// The attribute of the annotation ...
String value() default "";
int count() default 0;
Class<?> type() default Object.class;
Nullable nullable() default Nullable.NULLABLE;
}
4. Common cases
Cheers :: Commons :: Annotations framework has many common cases in actual project development.
4.1 Configuration parameter annotation
Developers can define the configuration parameters with the annotations provided by che. :: Commons :: Annotations :: Annotations. The configuration is performed in the code, so that the program can perform different logic according to the different configuration parameters during runtime.
For example, define an annotation for configured database connections @DataSource:
import org.eclipse.che.api.core.annotations.Nullable;
public @interface DataSource {
// Visit the relevant parameters of the database
String driverClass();
String url();
String username();
String password();
// Other configuration parameters
int maxConnections() default 10;
boolean autoCommit() default true;
}
4.2 Logging annotation
Developers can use the annotations provided by Che Core :: Commons :: Annotations framework to make simple log records.
For example, define an annotation for recording a method to call logs @Log:
public @interface Log {
// Log level
LogLevel level() default LogLevel.INFO;
// Log content
String value();
}
Developers can add @LOG annotations to the method to record information and parameters of the recording method.
5 Conclusion
Che Core :: Commons :: Annotations framework provides a simple and flexible way to use annotations for Java developers.This article conducted an in -depth analysis of the framework and introduced its basic use, functional characteristics and common cases.By applying the framework appropriately, developers can improve the readability and maintenance of the code and implement some specific functional requirements.It is hoped that readers can make full use of the framework in actual projects to improve development efficiency and code quality.
