Esper事件处理引擎_16_EPL 语法_8_NamedWindow
官方地址：http://www.espertech.com
Esper 事件引擎栏目：http://blog.csdn.net/xiaohulunb/article/category/2436609
EPL 语法代码见-GitHub代码地址：点击打开链接
涉及 Javabean,Listener,main 以 GitHub 包下为最新更，注释解释排版有问题可参考源码
EPL_8_NamedWindow
package com.framework_technology.esper.epl;
import com.framework_technology.esper.javabean.Apple;
import com.framework_technology.esper.javabean.Banana;
import com.java.annotation.document.Undigested;
/**
* API - 5.15. Creating and Using Named Windows
*
* 创建 NamedWindow
* 插入数据
* 查询数据、按条件触发查询数据
* 修改数据
* 删除数据
* 合并事件NamedWindow
* 对NamedWindow建立索引
*
* @author wei.Li by 14-8-21.
*/
public class EPL_8_NamedWindow {
/**
* 创建 window - ①在现有的数据类型上创建列
* <p>
* 语法：
* [context context_name]
* create window window_name.view_specifications
* [as] [select list_of_properties from] event_type_or_windowname
* [insert [where filter_expression]]
* <p>
* 1）context是关键字，后面跟着之前定义的context的名称。
* 关于context的内容，{@link EPL_2_Context_1,EPL_2_Context_2,EPL_2_Context_3}
* 2）create window后跟着要创建的named window的名字，且具有唯一性。名字后面紧跟着的“.”是用来连接事件过期策略的，即view。
* 常用的view有win:length，win:length_batch，win:time，win:time_batch，std:unique，std:groupwin及自定义view等等，并且特定的view可以连用。
* PS：view的相关内容{@link com.framework_technology.esper.views.View}
* 3）select子句表示将某个事件定义中的全部或者某些属性作为named window所维护的事件属性。
* 如果将某个事件的所有属性都加入到named window中，则可以通过select子句前的as连接事件名称，并且省略select子句。
*
* @return epl
*/
protected static String createWindowExistingType() {
String epl1 = "create window AppleWindow.win:keepall() as " + Apple.CLASSNAME;
String epl2 = "create window AppleWindow.win:time(30 sec) as " +
" select id as appleId, price as applePrice from OrderEvent";
return epl1;
}
/**
* 创建 window - ②自定义列的数据类型
* <p>
* 语法：
* [context context_name]
* create window window_name.view_specifications [as] (column_name column_type
* [,column_name column_type [,...])
*
* @return epl
*/
protected static String createWindowDefiningColumnsNamesAndTypes() {
String epl1 = "create window SecurityEvent.win:time(30 sec) " +
"(ipAddress string, userId String, numAttempts int, properties String[])";
@Undigested(Description = "what is schema ?")
String epl2 = "create schema SecurityData (name String, roles String[])";
String epl3 = "create window SecurityEvent.win:time(30 sec) " +
" (ipAddress string, userId String, secData SecurityData, historySecData SecurityData[])";
return epl1;
}
/**
* 创建 window - ③将存在的 window 数据插入到新创建的 window 中
* <p>
* 语法：[context context_name] create window window_name.view_specifications as windowname insert [where filter_expression]
* <p>
* windowname后面紧跟insert，表示将该window中的事件插入到新建的named window中。where filter_expression表示过滤插入的事件。
*
* @return epl
*/
protected static String populatingExistingNamedWindow() {
String epl1 = "create window BananaEventWindow.win:time(10) as AppleEventWindow insert where price > 100";
return epl1;
}
/**
* 销毁 window
*/
protected static void dropNamedWindow() {
//EPStatement epStatement = epAdministrator.createEPL("epl . . .");
//epStatement.destroy();
}
/**
* 插入数据到 window
* <p>
* 语法：insert into window_name [(property_names)] [values (value_expressions) 或者查询方式 select value_expressions]
* <p>
* 查询 window 的数据，与普通查询相同
*
* @return epl[]
*/
protected static String[] insertIntoDate() {
String query_1 =
"insert into OrdersWindow(orderId, symbol, price) values ('001', 'GE', 100)";
//epService.getEPRuntime().executeQuery(query);
String query_2 =
"insert into OrdersWindow(orderId, symbol, price) select '001', 'GE', 100";
//epService.getEPRuntime().executeQuery(query);
//新建 window - 插入数据 - 查询数据
String epl1 = "create window AppleWindow.win:keepall() as select id ,price from " + Apple.CLASSNAME;
String epl2 = "insert into AppleWindow select id,price from " + Apple.CLASSNAME;
String epl3 = "select * from AppleWindow(price>1) ";//查询方式与查询 javabean 方式相同
return new String[]{epl1, epl2, epl3};
}
/**
* 按照一定条件触发查询 window 的数据
* <p>
* 语法：
* on event_type[(filter_criteria)] [as stream_name]
* [insert into insert_into_def]
* select select_list
* from window_name [as stream_name]
* [where criteria_expression]
* [group by grouping_expression_list]
* [having grouping_search_conditions]
* [order by order_by_expression_list]
*
* @return EPL[]
*/
protected static String[] triggeredOnSelect() {
//新建 window - 插入数据
String epl1 = "create window AppleWindow.win:keepall() as select id ,price from " + Apple.CLASSNAME;
String epl2 = "insert into AppleWindow select id,price from " + Apple.CLASSNAME;
//触发条件查询
String epl3 = "on " + Banana.CLASSNAME + " as b select win.* from AppleWindow as win ";
// "where b.id ='1' group by win.price having win.price >0 order by win.price";
//将查询结果插入AppleWindow 中
String epl4 = "on " + Banana.CLASSNAME + " as b insert into AppleWindow select * from AppleWindow as win ";
// "where a.id ='1' group by win.price having win.price >1 order by win.price";
return new String[]{epl1, epl2, epl3};
}
/**
* 按照条件触发查询并删除 window 的数据
* on trigger
* select [and] delete select_list...
* ... (please see on-select for insert into, from, group by, having, order by)...
*
* @return epl[]
*/
protected static String[] triggeredOnSelectDelete() {
//新建 window - 插入数据
String epl1 = "create window AppleWindow.win:keepall() as select id ,price from " + Apple.CLASSNAME;
String epl2 = "insert into AppleWindow select id,price from " + Apple.CLASSNAME;
//触发条件查询
String epl3 = "on " + Apple.CLASSNAME + " as a select and delete window(win.*) from AppleWindow as win ";
//"where a.id ='1' group by win.price having win.price >1 order by win.price";
return new String[]{epl1, epl2, epl3};
}
/**
* 更新 Update window 数据
* <p>
* on event_type[(filter_criteria)] [as stream_name]
* update window_name [as stream_name]
* set mutation_expression [, mutation_expression [,...]]
* [where criteria_expression]
*
* @return epl[]
*/
protected static String[] updateNamedWindow() {
//simple example
String epl1 = "on UpdateOrderEvent update AllOrdersNamedWindow set price = 0";
String epl2 = "on ZeroVolumeEvent update AllOrdersNamedWindow set price = 0 where volume <= 0";
//对于OrderUpdateEvent或者FlushOrderEvent事件进入后触发修改 win set 的条件用 if else 匹配
String epl3 = "on pattern [every ord=OrderUpdateEvent(volume>0) or every flush=FlushOrderEvent] " +
"update AllOrdersNamedWindow as win" +
"set price = case when ord.price is null then flush.price else ord.price end" +
"where ord.id = win.id or flush.id = win.id";
String epl4 = "on UpdateEvent as upd" +
"update MyWindow as win" +
"set field_a = 1," +
"field_b = win.field_a," + // 把 a修改后的值 1 赋给 b
"field_c = initial.field_a ";// 把 a 更新前的值赋值给 c（关键字 initial）
/**
* 针对 epl4 ：
* update更新属性前会复制一份同样的事件暂存，比如initial这种操作就需要更新前的值，所以就需要我们实现序列化接口。
* 如果不想通过代码完成这个序列化要求，也可以通过配置完成。
* 另外还有以下几点需要注意：
a）需要更新的属性一定要是可写的
b）XML格式的事件不能通过此语句更新
c）嵌套属性不支持更新
*/
//Query 方式更新
String query = "update AllOrdersNamedWindow set volume = 0 where volumne = 0";
//epService.getEPRuntime().executeQuery(query);
return new String[]{epl1, epl2};
}
/**
* 删除 delete window 的数据
* <p>
* 语法：
* on event_type[(filter_criteria)] [as stream_name] (Pattern 匹配->on pattern [pattern_expression] [as stream_name])
* delete from window_name [as stream_name]
* [where criteria_expression]
*
* @return epl[]
*/
protected static String[] deleteNamedWindow() {
//事件触发
String epl1 = "on ZeroVolumeEvent delete from AllOrdersNamedWindow where volume <= 0";
String epl2 = "on NewOrderEvent(volume>0) as myNewOrders" +
"delete from AllOrdersNamedWindow as myNamedWindow " +
"where myNamedWindow.symbol = myNewOrders.symbol";
//Pattern 模式匹配
String epl3 = "on pattern [every timer:interval(10 sec)] delete from MyNamedWindow";
String epl4 = "on pattern [every ord=OrderEvent(volume>0) or every flush=FlushOrderEvent] " +
"delete from OrderWindow as win" +
"where ord.id = win.id or flush.id = win.id";
//Query 方式删除
String query = "delete from AllOrdersNamedWindow where volume <= 0";
//epService.getEPRuntime().executeQuery(query);
return new String[]{epl2, epl2};
}
/**
* 合并事件
* <p>
*
* @return epl[]
*/
protected static String[] MergeWindow() {
/*语法：
on event_type[(filter_criteria)] [as stream_name]
merge [into] window_name [as stream_name]
[where criteria_expression]
when [not] matched [and search_condition]
then [
insert [into streamname]
[ (property_name [, property_name] [,...]) ]
select select_expression [, select_expression[,...]]
[where filter_expression]
|
update set mutation_expression [, mutation_expression [,...]]
[where filter_expression]
|
delete
[where filter_expression]
]
[then [insert|update|delete]] [,then ...]
[when ... then ... [...]]
*/
/*
a.第一行和前面的用法都一样。
b.第二行的where语句将事件分为了matched（满足where条件）和not matched（不满足where条件）两类
c.第三行的when配合matched或者not matched表示“window中满足where条件的事件，执行下面的操作/window中不满足where条件的事件，执行下面的操作”。
search_condition为可选字段，表示再次过滤matched或not matched中的事件，只有没被过滤掉的事件才可以被then后面的语句操作。
d.第四行的insert语句和之前说的insert into不太一样。
虽然都表示插入事件，但是由于into streamname是可选，所以在只有insert关键字的情况下，会将触发的事件插入到当前的named window中。
如果要指明插入到别的named window中就要在insert之后带上into及window的名字。
再之后的圆括号中的内容表示要插入的事件的属性，一般情况是在将事件插入到别的window中时，用它来重命名第五行中列出的属性。
e.第五行实际是配合第四行一起使用的。select子句不可少，不然引擎就不知道要往window中插入什么内容了。
select的内容可以是*，也可以是属性列表。where语句再一次限制可插入的触发事件。注意select后面没有from，因为事件来源就是当时的触发事件。
f.第七行用来更新符合条件的事件，可更新单个或多个属性，where条件判断是否可进行更新操作。
g.第九行用来删除符合条件的事件，只包含关键字delete以及可选的where语句。
h.最后两行表示on merge中可以有多个when，每个when可以有多个then及insert或updata或delete语句，这样就能组成一个非常复杂的merge操作了。
*/
//在下面的例子中每一个匹配子句包含两个动作，一个动作中插入一个日志事件和第二动作插入、删除或更新
String epl1 = "on OrderEvent oe" +
" merge OrderWindow pw" +
" where pw.orderId = oe.orderId" +
" when not matched " +
" then insert into LogEvent select 'this is an insert example' as name" +
" then insert select *" +
" when matched and oe.deletedFlag=true" +
" then insert into LogEvent select 'this is a delete example' as name" +
" then delete" +
" when matched" +
" then insert into LogEvent select 'this is a update example' as name" +
" then update set pw.quantity = oe.quantity, pw.price = oe.price";
//根据条件判断，进行2此修改
String epl2 = "on OrderEvent oe" +
" merge OrderWindow pw" +
" where pw.orderId = oe.orderId" +
" when matched" +
" then update set clearorder(pw) where oe.price < 0" +
" then update set pw.quantity = oe.quantity, pw.price = oe.price where oe.price >= 0";
return new String[]{epl1, epl2};
}
/**
* 对named window中存放的事件的属性建立索引
* <p>
* 语法：
* create [unique] index index_name on named_window_name (property [hash| btree] [, property] [hash|btree] [,...] )
* <p>
* unique代表建立唯一索引，如果插入了重复的行，则会抛出异常并阻止重复行插入。
* 如果不使用此关键字，则表示可以插入重复行。
* index_name为索引的名称，named_window_name是要建立索引的named window。
* 后面的括号中包含named window中的属性以及索引类型。
* 索引类型分两种，hash索引不会排序，如果有=操作，建议使用此类型索引。
* btree索引基于排序二叉树，适合<, >, >=, <=, between, in等操作。
* 如果不显式声明hash或者btree，则默认为hash索引。
*
* @return epl[]
*/
protected static String[] IndexingNamedWindows() {
String epl1 = "create unique index UserProfileIndex on UserProfileWindow(userId, profileId) ";
String epl2 = "create index idx1 on TickEventWindow(symbol hash, buyPrice btree) ";
return new String[]{epl1, epl2};
}
}