com.github.datalking.common.meta.AnnotationAttributes Maven / Gradle / Ivy

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package com.github.datalking.common.meta;

import com.github.datalking.util.Assert;

import java.lang.annotation.Annotation;
import java.lang.reflect.Array;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * 保存注解的属性键值对，LinkedHashMap的子类
 *
 * @author yaoo on 4/13/18
 */
public class AnnotationAttributes extends LinkedHashMap {

    private static final String UNKNOWN = "unknown";

    private final Class annotationType;

    // 用于断言验证
    private final String displayName;

    public AnnotationAttributes() {
        this.annotationType = null;
        this.displayName = UNKNOWN;
    }

    public AnnotationAttributes(Class annotationType) {
        Assert.notNull(annotationType, "'annotationType' must not be null");
        this.annotationType = annotationType;
        this.displayName = annotationType.getName();
    }

    public AnnotationAttributes(Map map) {
        super(map);
        this.annotationType = null;
        this.displayName = UNKNOWN;
    }

    public Class annotationType() {
        return this.annotationType;
    }

    public String getString(String attributeName) {
        return getRequiredAttribute(attributeName, String.class);
    }

    public String[] getStringArray(String attributeName) {
        return getRequiredAttribute(attributeName, String[].class);
    }

    public boolean getBoolean(String attributeName) {
        return getRequiredAttribute(attributeName, Boolean.class);
    }

    public  N getNumber(String attributeName) {
        return (N) getRequiredAttribute(attributeName, Number.class);
    }

    public > E getEnum(String attributeName) {
        return (E) getRequiredAttribute(attributeName, Enum.class);
    }

    public  Class getClass(String attributeName) {
        return getRequiredAttribute(attributeName, Class.class);
    }

    public Class[] getClassArray(String attributeName) {
        return getRequiredAttribute(attributeName, Class[].class);
    }

    public AnnotationAttributes getAnnotation(String attributeName) {
        return getRequiredAttribute(attributeName, AnnotationAttributes.class);
    }

    public  A getAnnotation(String attributeName, Class annotationType) {
        return getRequiredAttribute(attributeName, annotationType);
    }

    public AnnotationAttributes[] getAnnotationArray(String attributeName) {
        return getRequiredAttribute(attributeName, AnnotationAttributes[].class);
    }

    public  A[] getAnnotationArray(String attributeName, Class annotationType) {
        Object array = Array.newInstance(annotationType, 0);
        return (A[]) getRequiredAttribute(attributeName, array.getClass());
    }

    public Class getAnnotationType() {
        return annotationType;
    }

    /**
     * 从输入的map中创建AnnotationAttributes
     *
     * @param map 注解所有属性键值对
     * @return AnnotationAttributes
     */
    public static AnnotationAttributes fromMap(Map map) {
        if (map == null) {
            return null;
        }
        if (map instanceof AnnotationAttributes) {
            return (AnnotationAttributes) map;
        }

        return new AnnotationAttributes(map);
    }


    private  T getAttribute(String attributeName, Class expectedType) {
        Object value = get(attributeName);

        return (T) value;
    }

    private  T getRequiredAttribute(String attributeName, Class expectedType) {
        Assert.notNull(attributeName, "'attributeName' must not be null or empty");
        Object value = get(attributeName);
        if (!expectedType.isInstance(value) && expectedType.isArray() && expectedType.getComponentType().isInstance(value)) {
            Object array = Array.newInstance(expectedType.getComponentType(), 1);
            Array.set(array, 0, value);
            value = array;
        }
        return (T) value;
    }

    private static Class getAnnotationType(String annotationType, ClassLoader classLoader) {
        if (classLoader != null) {
            try {
                return (Class) classLoader.loadClass(annotationType);
            } catch (ClassNotFoundException ex) {
                // Annotation Class not resolvable
            }
        }
        return null;
    }


    @Override
    public String toString() {
        Iterator> entries = entrySet().iterator();
        StringBuilder sb = new StringBuilder("{");
        while (entries.hasNext()) {
            Map.Entry entry = entries.next();
            sb.append(entry.getKey());
            sb.append('=');
            sb.append(entry.getValue().toString());
            sb.append(entries.hasNext() ? ", " : "");
        }
        sb.append("}");
        return sb.toString();
    }


}