Annotation Guide

Annotation

Feature Overview

This feature adds support for custom annotation on classes.

Prerequisite

None

Sweet Apex Example

@MyAnnotation(name='Test')
public class AnnotationDemo {
    public @interface MyAnnotation {
        public String name();

        public Integer number() default 10;
    }
}

Transpiled Apex

public class AnnotationDemo {
    public class MyAnnotation {
        private String m_name;
        private Integer m_number = 10;
        public MyAnnotation name(String m_name) {
            this.m_name = m_name;
            return this;
        }
        public String name() {
            return this.m_name;
        }
        public MyAnnotation number(Integer m_number) {
            this.m_number = m_number;
            return this;
        }
        public Integer number() {
            return this.m_number;
        }
    }
}

Sweet Annotations

public class SweetAnnotations implements Sweet.Annotations {
    private final Map<String, List<Object>> annotations = new Map<String, List<Object>>();

    public List<Object> getAnnotations(String name) {
        List<Object> aList = annotations.get(name);
        return aList == null ? new List<Object>() : aList;
    }

    public Object getAnnotation(String name) {
        List<Object> aList = getAnnotations(name);
        return aList.isEmpty() ? null : aList.get(0);
    }

    private void registerAnnotation(String targetName, Object annotation) {
        List<Object> aList = annotations.get(targetName);
        if(aList == null) {
            aList = new List<Object>();
        }
        aList.add(annotation);
        annotations.put(targetName, aList);
    }

    {
        registerAnnotation(AnnotationDemo.class.getName(), new AnnotationDemo.MyAnnotation().name('Test'));
    }
}

Usage

Define custom annotations.

public @interface MyAnnotation {
    public String name();

    public Integer number() default 10;
}

Apply custom annotations on classes.

@MyAnnotation(name='Test')
public class AnnotationDemo {
}

Retrieve annotation information from the instance of the class.

AnnotationDemo demo = new AnnotationDemo();
AnnotationDemo.MyAnnotation myAnn = (AnnotationDemo.MyAnnotation)Sweet.getAnnotation(demo);
System.debug(myAnn.name());

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