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• A partition is defined with the 'symbol' attribute of the StockStream, which means that the processing will take place independently for events of each symbol.
• Processes the events received through the FilteredStockStream.
• First it looks for an event e1 with the condition price greater than 20.
• Then it looks for one or more events, e2 with a condition

  • ((e2[last].price

    is

    null)

    and

    price>=e1.price)

    is

    used

    to

    check

    the

    first

    event

    after

    e1,

    i.e.

    (e2[last].price

    is

    null)

    returns

    true

    since

    there

    is

    no

    last

    event

    in

    e2.

    Then

    it

    checks

    for

    the

    condition

    where

    the

    current

    event

    price

    is

    greater

    than

    e1

    price.

     

  • ((not

    (e2[last].price

    is

    null))

    and

    price>=e2[last].price)

    this

    part

    is

    for

    any

    subsequent

    events.

    In

    this

    case

    the

    last

    of

    e2

    is

    not

    null,

    and

    we

    check

    whether

    the

    price

    of

    the

    current

    event

    is

    greater

    than

    the

    last

    event.

    i.e.

    we

    are

    looking

    for

    one

    or

    more

    events

    with

    continuous

    price

    increase

    from

    this

    whole

    condition.

     

• Then we look for another event with a price drop from the last e2 event from the condition e3condition e3=FilteredStockStream[price<e2[last].price]
• From the select clause we select the attributes e1attributes e1.price as priceInitial, e2[last].price as pricePeak, e3.price as priceAfterPeak
• Finally the event is output to the PeakStream.

Prerequisites

See Prerequisites in CEP Samples Setup page.

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