1. <Insert Picture Here>
A General Extension System for Event Processing Languages
Alexandre Alves - Oracle CEP
Monday, July 11, 2011

2. Agenda DEBS2011
• Scenario 1
• String manipulation (programming-in-the-small)
• Blending CQL and Java
• Architecture
• Scenario 2 Text
• Geo-fence (extensibility)
• Blending CQL and Spatial
• Architecture
• Q/A
Monday, July 11, 2011

3. Scenario 1: DEBS2011
Programming-in-the-small
• Correlate security price changes to real-time event
news.
Text
Monday, July 11, 2011

4. Scenario 1: DEBS2011
Programming-in-the-small
Oracle CQL
Processor
SELECT *
FROM Text
news [RANGE 1 HOUR],
stock_tick [RANGE 1 HOUR]
WHERE /* join-criteria */
Monday, July 11, 2011

5. Scenario 1: DEBS2011
Programming-in-the-small
• Problem: the NEWS feed is a unstructured (String),
hence not trivial to identify its event properties
• For example, a naive join criteria is to look for a stock’s
symbol
• The problem of parsing a String can be solved using
Regular Expressions. Text
• Regular Expressions and other programming-in-the-
small tasks have long been solved by general
purpose programming languages
• Can we leverage this within an event processing
language (e.g. CQL)?
Monday, July 11, 2011

6. Java Regular Expressions DEBS2011
• Let’s look at a simple solution to the problem using
Java:
Matcher matcher =
Text
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher
(message);
if (matcher.find()) {
Matches three letter
symbol = message.substring(matcher.start() + 1, symbols, separated by
leading and trailing
matcher.end() - 1)); white-spaces
}
Monday, July 11, 2011

7. Blending CQL with Java DEBS2011
CREATE VIEW filtered_news(message, matcher) AS
SELECT
message,
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message) as
matcher
FROM news [RANGE 1 HOUR] Text
SELECT
location, item_description, message
FROM filtered_news, stock_tick[RANGE 1 HOUR]
WHERE
matcher.find() = true AND
filtered_news.message.substring(matcher.start() + 1,
matcher.end() - 1) = stock_tick.symbol
Monday, July 11, 2011

8. Blending CQL with Java DEBS2011
CQL char conversion
to Java String
CREATE VIEW filtered_news(message, matcher) AS
SELECT
message,
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message) as matcher
FROM news [RANGE 1 HOUR]
Text
SELECT
location, item_description, message Method invocation
FROM filtered_news, stock_tick[RANGE 1 HOUR]
WHERE
matcher.find() = true AND Static method
filtered_news.message.substring(matcher.start() + 1, invocation
matcher.end() - 1) = stock_tick.symbol
Monday, July 11, 2011

9. Blending CQL with Java DEBS2011
‘matcher’ is a Java
Object, and treated as
CREATE VIEW filtered_news(message, matcher) AS
a complex type by
SELECT CQL
message,
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message) as matcher
FROM news [RANGE 1 HOUR]
Text
SELECT Overload of CQL ‘+’
location, item_description, message operator to handle
FROM filtered_news, stock_tick[RANGE 1 HOUR] Java Integer
WHERE
matcher.find() = true AND Overload of CQL
filtered_news.message.substring(matcher.start() + 1, equality to handle
matcher.end() - 1) = stock_tick.symbol Java String
Monday, July 11, 2011

10. Architecture DEBS2011
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message)
(message)
• Is this symbol:
• Text
A stream attribute (e.g. message)?
• A stream alias (e.g. FROM S1 as A)
• A CQL function (e.g. SELECT myfunc())
• The l-value of complex type (e.g. myObj.myMethod())
• A constructor
• A (static) method
• A class name
Monday, July 11, 2011

11. Architecture DEBS2011
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message)
(message)
• To be able to semantically compile symbols, we need
to have type information.Text
• However, CQL is not aware of Java, nor should it be.
• There is a need of a generic type-system, and an
extension model for providers to plug-in their own
languages
Monday, July 11, 2011

12. Architecture DEBS2011
CQL Parser
Semantic Type
Analyzer Registry
Text
Code
Generator Java
Type-System
Code
Executor
Monday, July 11, 2011

13. Architecture DEBS2011
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message)
(message)
ComplexType
“Pattern”
Text
Type fields
Registry
methods
Java
Type-System
Monday, July 11, 2011

14. Architecture DEBS2011
ComplexType
fields
“Pattern” Type
Registry
methods
Text
Java
Type-System
CQL deals with a ‘complex type’ abstraction, and
does not know of its ‘Java Language’ binding.
Monday, July 11, 2011

15. Architecture DEBS2011
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message)
(message)
Pattern
ComplexType
fields Text
Find a “compile” method and its return type
methods
Monday, July 11, 2011

16. Architecture DEBS2011
Pattern.compile("[.,; ][A-Z][A-Z][A-Z][.,; ]").matcher(message)
Pattern Matcher
ComplexType ComplexType Text
fields fields Store ‘matcher’ as
methods methods a stream/view attribute
Monday, July 11, 2011

17. Architecture DEBS2011
Extensible Language
stream 1 * attribute Type
<<is-of>>
‘matcher’ is an attribute of the view
of type ‘java.util.regex.Matcher’ ComplexType
Text <<metadata binding>>
Extension Java Language
CREATE VIEW filtered_news(message, matcher)
Java Class
Monday, July 11, 2011

18. Extensibility DEBS2011
Extensible Language
stream 1 * attribute Type
<<is-of>>
ComplexType
Text <<metadata binding>>
How do we know which Extension Java Language
‘language extension’ to use?
How to provide new Java Class
extensions?
Monday, July 11, 2011

19. Scenario 2: DEBS2011
Spatial Integration
• Targeted marketing for a mobile subscriber
• CEP application checks if the location of the subscriber is
within the distance of a registered shop
Text
Text
Oracle Spatial
Shop
id: CHAR
geometry: SDO_GEOMETRY
Monday, July 11, 2011

20. Blending CQL with Spatial DEBS2011
CREATE VIEW CustomerLocation-Stream(point, custId) AS
SELECT createPoint@spatial(lng, lat) as point, custId
FROM Location-Stream
point is a spatial type
SELECT loc.custId, shop.id Text
FROM
CustomerLocation-Stream[NOW] AS loc, Shop as shop
WHERE
contain@spatial(shop.geometry, loc.point, 2.0d) ‘spatial’ link points to
Oracle Spatial
‘extension’, where
‘contain’ function
resides
Monday, July 11, 2011

21. Architecture DEBS2011
CQL
CQL link specifies language
extension, which are plugged
into the system as a CQL
cartridge
Text <<link>>
CQL Cartridge
Cartridge
contain@spatial(shop.geometry, loc.point, 2.0d)
Monday, July 11, 2011

22. Conclusion DEBS2011
• Blending of CQL with other languages allow for the
creation of feature-rich CEP applications while still
being highly descriptive
• Example:
• String manipulation using Java
Text
• Geo-fencing using Oracle Spatial
• Generic frameworks allows for the dynamic plugin of
extensions (cartridges)
Monday, July 11, 2011