esper参考手册esper_reference.pdf

Esper Reference

Version 4.11.0

by Esper Team and EsperTech Inc. [http://esper.codehaus.org]

Copyright 2006 - 2014 by EsperTech Inc.

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Preface ........................................................................................................................... xxi

1. Technology Overview .................................................................................................. 1

1.1. Introduction to CEP and event series analysis ...................................................... 1

1.2. CEP and relational databases ............................................................................. 1

2.2.2. Expression as Key or Index Value ............................................................ 6

2.3. Dynamic Event Properties ................................................................................... 7

2.4. Fragment and Fragment Type ............................................................................. 9

2.5. Plain-Old Java Object Events .............................................................................. 9

2.5.1. Java Object Event Properties .................................................................. 10

2.5.2. Property Names ..................................................................................... 11

2.5.3. Parameterized Types .............................................................................. 12

2.5.4. Setter Methods for Indexed and Mapped Properties .................................. 12

2.5.5. Known Limitations .................................................................................. 13

2.6. java.util.Map Events .......................................................................................... 13

2.7.2. Object-Array Properties .......................................................................... 19

2.7.3. Object-Array Supertype .......................................................................... 20

2.7.4. Advanced Object-Array Property Types ................................................... 21

2.8. org.w3c.dom.Node XML Events ......................................................................... 23

2.8.1. Schema-Provided XML Events ................................................................ 25

2.8.2. No-Schema-Provided XML Events ........................................................... 30

2.8.3. Explicitly-Configured Properties ............................................................... 30

2.9. Additional Event Representations ....................................................................... 32

2.10. Updating, Merging and Versioning Events ........................................................ 33

2.11. Coarse-Grained Events ................................................................................... 33

3.4. Filters and Where-clauses ................................................................................. 40

3.5. Time Windows .................................................................................................. 42

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3.5.1. Time Window ......................................................................................... 42

3.5.2. Time Batch ............................................................................................ 43

3.6. Batch Windows ................................................................................................. 44

3.7. Aggregation and Grouping ................................................................................. 45

4.2.1. Context-Provided Properties ................................................................... 51

4.2.2. Keyed Segmented Context ..................................................................... 51

4.2.3. Hash Segmented Context ....................................................................... 56

4.2.4. Category Segmented Context ................................................................. 59

4.2.5. Non-Overlapping Context ........................................................................ 61

4.2.6. Overlapping Context ............................................................................... 63

4.2.7. Context Conditions ................................................................................. 66

4.3. Context Nesting ................................................................................................ 69

4.3.1. Built-In Nested Context Properties ........................................................... 71

4.4. Partitioning Without Context Declaration ............................................................. 72

5.2.1. Specifying Time Periods ......................................................................... 79

5.2.2. Using Comments .................................................................................... 79

5.2.3. Reserved Keywords ............................................................................... 80

5.2.4. Escaping Strings .................................................................................... 81

5.2.5. Data Types ............................................................................................ 81

5.2.6. Using Constants and Enum Types .......................................................... 84

5.2.7. Annotation ............................................................................................. 85

5.2.8. Expression Declaration ........................................................................... 90

5.2.9. Script Declaration ................................................................................... 92

5.2.10. Referring to a Context .......................................................................... 92

5.3.6. Choosing event properties and events from a pattern ............................... 97

5.3.7. Selecting insert and remove stream events .............................................. 98

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5.3.8. Qualifying property names and stream names .......................................... 98

5.3.9. Select Distinct ........................................................................................ 99

5.3.10. Transposing an Expression Result to a Stream ..................................... 100

5.3.11. Selecting EventBean instead of Underlying Event ................................. 100

5.5. Specifying Search Conditions: the Where Clause .............................................. 110

5.6. Aggregates and grouping: the Group-by Clause and the Having Clause .............. 110

5.6.1. Using aggregate functions ..................................................................... 110

5.6.2. Organizing statement results into groups: the Group-by clause ................ 111

5.6.3. Selecting groups of events: the Having clause ........................................ 114

5.6.4. How the stream filter, Where, Group By and Having clauses interact ........ 115

5.6.5. Comparing Keyed Segmented Context, the Group By clause and the

std:groupwin view .......................................................................................... 116

5.7. Stabilizing and Controlling Output: the Output Clause ........................................ 117

5.7.1. Output Clause Options ......................................................................... 117

5.10.2. Merging Streams By Event Type ......................................................... 129

5.10.3. Merging Disparate Types of Events: Variant Streams ............................ 130

5.10.4. Decorated Events ............................................................................... 131

5.10.5. Event as a Property ............................................................................ 131

5.10.6. Instantiating and Populating an Underlying Event Object ....................... 132

5.10.7. Transposing an Expression Result ....................................................... 132

5.10.8. Select-Clause Expression And Inserted-Into Column Event Type ............ 132

5.11. Subqueries .................................................................................................... 133

5.11.1. The 'exists' Keyword ........................................................................... 136

5.11.2. The 'in' and 'not in' Keywords .............................................................. 137

5.12. Joining Event Streams ................................................................................... 142

5.12.1. Introducing Joins ................................................................................ 142