同步比较器工具
项目中，我们常常遇到需要同步数据的情况，这个时候我们需要将 旧数据 与 新数据 做对比。处理三种情况的数据：①存在于旧数据，不存在于新数据的信息，进行移除操作；②存在于旧数据，也存在于新数据的信息，进行更新操作；③不存在于旧数据，存在于新数据的信息，进行添加操作。同步比较器基类/**
* 基本 同步比较器
* @author linling
*
*/
public class BasicComparator {
public interfaceListCompareHandler<T> {
public void handlerNewEntry(T t);
public void handlerNoMoreEntry(T t);
public void handlerSameEntry(T t);
/**
* if oneList contain otherList return boolean , Otherwise return false;
* @param oneList
* @param otherList
* @return
*/
public boolean contain(List<T> oneList, T t) throws Exception;
}
public <T> void compareTo(List<T> oldList, List<T> newList, ListCompareHandler<T> handler)throws Exception{
for(Iterator<T> iter = oldList.iterator(); iter.hasNext();) {
T t = iter.next();
if(!handler.contain(newList, t)) {
handler.handlerNoMoreEntry(t);
}
}
for(Iterator<T> iter = newList.iterator(); iter.hasNext();) {
T t = iter.next();
if(handler.contain(oldList, t)) {
handler.handlerSameEntry(t);
}else {
handler.handlerNewEntry(t);
}
}
}
public interface SetCompareHandler<T> {
public void handlerNewEntry(T t);
public void handlerNoMoreEntry(T t);
public void handlerSameEntry(T t);
/**
* if oneSet contain otherSet return true, Otherwise return false;
* @param oneSet
* @param otherSet
* @return
*/
public boolean contain(Set<T> oneSet, T t) throws Exception;
}
public <T> void compareTo(Set<T> oldSet, Set<T> newSet, SetCompareHandler<T> handler) throws Exception{
for(Iterator<T> iter = oldSet.iterator(); iter.hasNext();) {
T t = iter.next();
if(!handler.contain(newSet, t)) {
handler.handlerNoMoreEntry(t);
}
}
for(Iterator<T> iter = newSet.iterator();iter.hasNext();) {
T t = iter.next();
if(handler.contain(oldSet, t)) {
handler.handlerSameEntry(t);
}else {
handler.handlerNewEntry(t);
}
}
}
public interface MapCompareHandler<K,V> {
public void handlerNewEntry(Map.Entry<K, V> entry);
public void handlerNoMoreEntry(Map.Entry<K, V> entry);
public void handlerSameEntry(Map.Entry<K, V> entry);
/**
* if oneMap contain otherMap return true, Otherwise return false;
* @param oneMap
* @param otherMap
* @return
*/
public boolean contain(Map<K,V> oneMap, Map.Entry<K, V> entry) throws Exception;
}
public <K,V> void compareTo(Map<K,V> newMap, Map<K,V> oldMap, MapCompareHandler<K,V> handler) throws Exception{
Set<Map.Entry<K, V>> oldEntrySet = oldMap.entrySet();
for(Iterator<Map.Entry<K, V>> iter = oldEntrySet.iterator(); iter.hasNext();) {
Map.Entry<K, V> entry = iter.next();
if(!handler.contain(newMap, entry)) {
handler.handlerNoMoreEntry(entry);
}
}
Set<Map.Entry<K, V>> newEntrySet = newMap.entrySet();
for(Iterator<Map.Entry<K, V>> iter = newEntrySet.iterator(); iter.hasNext();) {
Map.Entry<K, V> entry = iter.next();
if(handler.contain(oldMap, entry)) {
handler.handlerSameEntry(entry);
}else {
handler.handlerNewEntry(entry);
}
}
}
}
下面是实现了上面 基本比较器的基本类，负责初始化List和Set比较器的handler操作。我在项目中只需要集成下面这个类就好。
package com.bayern;
import java.util.List;
import java.util.Set;
/**
* 基本 全同步比较器基础类
* @author linling
*
* @param <VO>
*/
public abstract class ComparatorAdapter<VO> extends BasicComparator {
@SuppressWarnings("rawtypes")
protected BasicService basicService;
public abstract void setBasicService(BasicService<VO> basicService);
public class ListCompareHandlerAdapter implements ListCompareHandler<VO> {
public void handlerNewEntry(VO vo) {
basicService.save(vo);
}
public void handlerNoMoreEntry(VO vo) {
basicService.delete(vo);
}
public void handlerSameEntry(VO vo) {
basicService.update(vo);
}
/**
* 该方法必须被子类覆盖重写
*/
@Override
public boolean contain(List<VO> oneList, VO t) throws Exception{
throw new Exception();
}
}
public class SetCompareHandlerAdapter implements SetCompareHandler<VO> {
public void handlerNewEntry(VO vo) {
basicService.save(vo);
}
public void handlerNoMoreEntry(VO vo) {
basicService.delete(vo);
}
public void handlerSameEntry(VO vo) {
basicService.update(vo);
}
/**
* 该方法必须被子类覆盖重写
*/
@Override
public boolean contain(Set<VO> oneSet, VO t)throws Exception{
throw new Exception();
}
}
}
最后，来个实际的比较器：
package com.bayern;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
import javax.annotation.Resource;
import org.springframework.stereotype.Component;
/**
* 摄像头比较器
* @author linling
*
*/
@Component(value="cameraComparator")
public class CameraComparator extends ComparatorAdapter<VoCamera>{
public CameraComparator(){
}
@Resource(name="cameraServiceImpl")
@Override
public void setBasicService(BasicService<VoCamera> basicService) {
super.basicService = basicService;
}
public class CameraComparatorHandler extends ListCompareHandlerAdapter{
private long schoolId;
public CameraComparatorHandler(long schoolId) {
this.schoolId = schoolId;
}
@Override
public boolean contain(List<VoCamera> oneList, VoCamera t)throws Exception{
boolean exists = false;
for(Iterator<VoCamera> iter = oneList.iterator(); iter.hasNext();) {
VoCamera vo = iter.next();
if(t.getCameraSignature().equals(vo.getCameraSignature()) && schoolId == vo.getSchoolId().longValue()) {
if(!CommonUtils.stringIsBlank(vo.getCameraId()) && CommonUtils.stringIsBlank(t.getCameraId())) {
t.setCameraId(vo.getCameraId());
}
exists = true;
break;
}
}
return exists;
}
@Override
public void handlerNewEntry(VoCamera vo) {
vo.setCameraId(UUID.randomUUID().toString());
super.handlerNewEntry(vo);
}
}
}
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