ClassWrapper.java 文件源码

/**
 * Get class field
 *
 * @param fieldName Field's name
 * @param type Field's type class
 * @param <V> Field's type
 * @return {@link FieldWrapper} object or empty, if field wasn't found
 */
@Contract("null, null -> fail")
@SuppressWarnings("unchecked")
public <V> Optional<FieldWrapper<V>> getField(String fieldName, Class<V> type) {
    /* Check arguments */
    if(fieldName == null) throw new IllegalStateException("Field name shouldn't be null!");
    if(type == null) throw new IllegalStateException("Field type shouldn't be null!");

    /* Try to find cached field */
    FieldInfo fieldInfo = new FieldInfo(fieldName, type);

    /* Get field */
    Integer found = FIELD_INDEX.get(fieldInfo);
    Field[] field = new Field[] { found != null ? FIELD_CACHE.get(found) : null };
    field[0] = field[0] != null ? field[0] : findDeclaredField(fieldName, type);
    if(field[0] == null) return Optional.empty();

    /* Wrap field */
    return Optional.of((FieldWrapper<V>)FIELDWRAPPER_CACHE.computeIfAbsent(found,
            k -> MethodHandleFieldWrapper.of(this, field[0], type)));
}