Android Class Field Find findField(Class clazz, String fieldName)

Description

Look up a field in a class and set it to accessible.

Declaration

public static Field findField(Class<?> clazz, String fieldName) 

Method Source Code

//package com.java2s;

import java.lang.reflect.Field;

import java.util.HashMap;

public class Main {
    private static final HashMap<String, Field> fieldCache = new HashMap<String, Field>();

    /**//from  w  w w.ja v  a2  s  .c  om
     * Look up a field in a class and set it to accessible. The result is cached.
     * If the field was not found, a {@link NoSuchFieldError} will be thrown.
     */
    public static Field findField(Class<?> clazz, String fieldName) {
        StringBuilder sb = new StringBuilder(clazz.getName());
        sb.append('#');
        sb.append(fieldName);
        String fullFieldName = sb.toString();

        if (fieldCache.containsKey(fullFieldName)) {
            Field field = fieldCache.get(fullFieldName);
            if (field == null)
                throw new NoSuchFieldError(fullFieldName);
            return field;
        }

        try {
            Field field = findFieldRecursiveImpl(clazz, fieldName);
            field.setAccessible(true);
            fieldCache.put(fullFieldName, field);
            return field;
        } catch (NoSuchFieldException e) {
            fieldCache.put(fullFieldName, null);
            throw new NoSuchFieldError(fullFieldName);
        }
    }

    private static Field findFieldRecursiveImpl(Class<?> clazz,
            String fieldName) throws NoSuchFieldException {
        try {
            return clazz.getDeclaredField(fieldName);
        } catch (NoSuchFieldException e) {
            while (true) {
                clazz = clazz.getSuperclass();
                if (clazz == null || clazz.equals(Object.class))
                    break;

                try {
                    return clazz.getDeclaredField(fieldName);
                } catch (NoSuchFieldException ignored) {
                }
            }
            throw e;
        }
    }
}

Related

1. findFieldRecursiveImpl(Class clazz, String fieldName)
2. findFirstFieldByExactType(Class clazz, Class type)
3. getAdditionalStaticField(Class clazz, String key)
4. getFields(Class cs)