com.luhuiguo.fastdfs.proto.mapper.ObjectMetaData Maven / Gradle / Ivy
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package com.luhuiguo.fastdfs.proto.mapper;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* 映射对象元数据
*
*
* 映射对象元数据必须由{@code @FdfsColumn}注解
*
*
* @author tobato
*
*/
public class ObjectMetaData {
/** 日志 */
private static Logger LOGGER = LoggerFactory.getLogger(ObjectMetaData.class);
/** 映射对象类名 */
private String className;
/** 映射列(全部) */
private List fieldList = new ArrayList();
/** 动态计算列(部分)fieldList包含dynamicFieldList */
private List dynamicFieldList = new ArrayList();
/** FieldsTotalSize */
private int fieldsTotalSize = 0;
/**
* 映射对象元数据构造函数
*
* @param genericType
*/
public ObjectMetaData(Class genericType) {
// 获得对象类名
this.className = genericType.getName();
this.fieldList = praseFieldList(genericType);
// 校验映射定义
validatFieldListDefine();
}
public String getClassName() {
return className;
}
public List getFieldList() {
return Collections.unmodifiableList(fieldList);
}
/**
* 解析映射对象数据映射情况
*
* @return
*/
private List praseFieldList(Class genericType) {
Field[] fields = genericType.getDeclaredFields();
List mapedFieldList = new ArrayList();
for (int i = 0; i < fields.length; i++) {
if (fields[i].isAnnotationPresent(FdfsColumn.class)) {
FieldMetaData fieldMetaData = new FieldMetaData(fields[i], fieldsTotalSize);
mapedFieldList.add(fieldMetaData);
// 计算偏移量
fieldsTotalSize += fieldMetaData.getRealeSize();
// 如果是动态计算列
if (fieldMetaData.isDynamicField()) {
dynamicFieldList.add(fieldMetaData);
}
}
}
return mapedFieldList;
}
/**
* 检查数据列定义
*
*
* 为了减少编码的错误，检查数据列定义是否存在列名相同或者索引定义相同(多个大于0相同的)的
*
*/
private void validatFieldListDefine() {
for (FieldMetaData field : fieldList) {
validatFieldItemDefineByIndex(field);
}
}
/**
* 检查按索引映射
*
* @param field
*/
private void validatFieldItemDefineByIndex(FieldMetaData field) {
for (FieldMetaData otherfield : fieldList) {
if (!field.equals(otherfield) && (field.getIndex() == otherfield.getIndex())) {
Object[] param = { className, field.getFieldName(), otherfield.getFieldName(), field.getIndex() };
LOGGER.warn("在类{}映射定义中{}与{}索引定义相同为{}(请检查是否为程序错误)", param);
}
}
}
/**
* 是否有动态数据列
*
* @return
*/
private boolean hasDynamicField() {
for (FieldMetaData field : fieldList) {
if (field.isDynamicField()) {
return true;
}
}
return false;
}
/**
* 获取动态数据列长度
*
* @return
* @throws NoSuchMethodException
* @throws InvocationTargetException
* @throws IllegalAccessException
*/
private int getDynamicFieldSize(Object obj, Charset charset)
throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
int size = 0;
for (FieldMetaData field : dynamicFieldList) {
size = size + field.getDynamicFieldByteSize(obj, charset);
}
return size;
}
/**
* 获取固定参数对象总长度
*
* @return
*/
public int getFieldsFixTotalSize() {
if (hasDynamicField()) {
throw new FdfsColumnMapException(
className + " class hasDynamicField, unsupport operator getFieldsTotalSize");
}
return fieldsTotalSize;
}
/**
* 获取需要发送的报文长度
*
* @param obj
* @param charset
* @return
* @throws NoSuchMethodException
* @throws InvocationTargetException
* @throws IllegalAccessException
*/
public int getFieldsSendTotalByteSize(Object bean, Charset charset) {
if (!hasDynamicField()) {
return fieldsTotalSize;
} else {
return getDynamicTotalFieldSize(bean, charset);
}
}
/**
* 获取动态属性长度
*
* @param bean
* @param charset
* @return
*/
private int getDynamicTotalFieldSize(Object bean, Charset charset) {
try {
int dynamicFieldSize = getDynamicFieldSize(bean, charset);
return fieldsTotalSize + dynamicFieldSize;
} catch (NoSuchMethodException ie) {
LOGGER.debug("Cannot invoke get methed: ", ie);
throw new FdfsColumnMapException(ie);
} catch (IllegalAccessException iae) {
LOGGER.debug("Illegal access: ", iae);
throw new FdfsColumnMapException(iae);
} catch (InvocationTargetException ite) {
LOGGER.debug("Cannot invoke method: ", ite);
throw new FdfsColumnMapException(ite);
}
}
/**
* 导出调试信息
*
* @param objectMap
*/
public void dumpObjectMetaData() {
LOGGER.debug("dump class={}", className);
LOGGER.debug("----------------------------------------");
for (FieldMetaData md : fieldList) {
LOGGER.debug(md.toString());
}
}
}