com.poiji.util.ReflectUtil Maven / Gradle / Ivy

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package com.poiji.util;

import com.poiji.annotation.ExcelCellRange;
import com.poiji.exception.IllegalCastException;
import com.poiji.exception.PoijiInstantiationException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class ReflectUtil {
    public static  T newInstanceOf(Class type) {
        T obj;
        try {
            Constructor constructor = type.getDeclaredConstructor();
            if (!constructor.isAccessible()) {
                constructor.setAccessible(true);
            }
            obj = constructor.newInstance();
        } catch (Exception ex) {
            throw new PoijiInstantiationException("Cannot create a new instance of " + type.getName(), ex);
        }

        return obj;
    }


    /**
     * Finds a particular annotation on a class and checks subtypes marked with ExcelCellRange recursively.
     * 
     * Recursively does not refer to super classes.
     */
    public static  Collection findRecursivePoijiAnnotations(Class typeToInspect,
        Class annotationType) {
        List annotations = new ArrayList<>();

        for (Field field : typeToInspect.getDeclaredFields()) {
            Annotation excelCellRange = field.getAnnotation(ExcelCellRange.class);
            if (excelCellRange != null) {
                annotations.addAll(findRecursivePoijiAnnotations(field.getType(), annotationType));
            } else {
                A fieldAnnotation = field.getAnnotation(annotationType);
                if (fieldAnnotation != null) {
                    annotations.add(fieldAnnotation);
                }
            }
        }

        return annotations;
    }

    public static void setFieldData(Field field, Object o, Object instance) {
        try {
            field.setAccessible(true);
            field.set(instance, o);
        } catch (IllegalAccessException e) {
            throw new IllegalCastException("Unexpected cast type {" + o + "} of field" + field.getName());
        }
    }
}