Java Reflection Field Set setField(String fieldName, Object instance, Object value)

Description

set Field

License

Open Source License

Declaration

public static boolean setField(String fieldName, Object instance, Object value) 

Method Source Code

//package com.java2s;

import java.lang.reflect.Field;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class Main {
    private static final Map<String, Field> FIELD_CACHE = new ConcurrentHashMap<>();

    public static boolean setField(String fieldName, Object instance, Object value) {
        Field field = fieldFor(instance, fieldName);
        return field != null && setField(field, instance, value);
    }/*from  w ww .  java 2 s  .c  om*/

    public static boolean setField(Field field, Object instance, Object value) {
        try {
            field.setAccessible(true);
            field.set(instance, value);
            return true;
        } catch (IllegalAccessException ex) {
            return false;
        }
    }

    public static Field fieldFor(Object object, String name) {
        try {
            String id = fieldIdentifier(object.getClass(), name);

            if (FIELD_CACHE.containsKey(id)) {
                return FIELD_CACHE.get(id);
            }
            Field field = object.getClass().getDeclaredField(name);

            FIELD_CACHE.put(id, field);
            return field;
        } catch (NoSuchFieldException ignored) {
            return null;
        }
    }

    private static String fieldIdentifier(Class<?> cls, String fieldName) {
        return cls.getName() + "||" + fieldName;
    }

    private static String fieldIdentifier(Field field) {
        return field.getDeclaringClass().getName() + "||" + field.getName();
    }
}

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