Dieser Ausdruck setzt eine Zeitlinie (siehe Abschnitt Verarbeitung von Daten, die sich mit der Zeit ändern) aus wiederholten Aufrufen eines untergeordneten Ausdrucks zusammmen. Normalerweise wird der Ausdruck timelineoperation zusammen mit dem Ausdruck "intervalvalue" (siehe intervalvalue) verwendet. Gemeinsam ermöglichen diese beiden Ausdrücke, dass andere Ausdrücke Operationen für Werte aus Zeitlinien ausführen (als ob es sich um Basiselementwerte handeln würde) und dass die resultierenden Daten anschließend in einer Zeitlinie neu zusammengesetzt werden.
Nachfolgend ist kurz beschrieben, wie sich der Ausdruck timelineoperation zur Auswertungszeit verhält:
Das zuvor beschriebene Verhalten bedeutet, dass die verschachtelten Ausdrücke in keinem Fall Kenntnis darüber haben müssen, dass sie im Rahmen der Verarbeitung von Zeitlinien eingesetzt werden. Darüber hinaus ist die Verarbeitung effizient, weil Ausdrücke nur für diejenigen Datumsangaben aufgerufen werden, an denen sich der Wert der Eingabezeitlinien ändert.
<?xml version="1.0" encoding="UTF-8"?>
<RuleSet name="Example_timelineoperation"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation=
"http://www.curamsoftware.com/CreoleRulesSchema.xsd">
<Class name="Person">
<!--
true during a person's lifetime; false before date of birth,
and false again after date of death (if any)
-->
<Attribute name="isAliveTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Boolean"/>
</javaclass>
</type>
<derivation>
<specified/>
</derivation>
</Attribute>
<!--
The assets owned by the person, at some time or another. Each
asset's value may vary over time.
-->
<Attribute name="ownedAssets">
<type>
<javaclass name="List">
<ruleclass name="Asset"/>
</javaclass>
</type>
<derivation>
<specified/>
</derivation>
</Attribute>
<!--
The total value of the assets owned by the person (or by the
person's estate, if the person has died).
-->
<Attribute name="totalAssetValueTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Number"/>
</javaclass>
</type>
<derivation>
<!--
Total the value of all the owned assets. The value of each
asset may change over time.
-->
<!--
<timelineoperation> will create a timeline from the series
of <sum> calculations performed within it.
Each execution of <sum> will calculate the total for a
particular day; <timelineoperation> will assemble these
daily totals into a timeline of numbers.
-->
<timelineoperation>
<sum>
<!--
For each owned asset, get its countable-value timeline.
-->
<dynamiclist>
<list>
<reference attribute="ownedAssets"/>
</list>
<listitemexpression>
<!--
Wrap the timeline returned by
countableValueTimeline, so that the <sum> thinks
that it is operating on a list of numbers, not a
list of timelines.
-->
<intervalvalue>
<reference attribute="countableValueTimeline">
<current/>
</reference>
</intervalvalue>
</listitemexpression>
</dynamiclist>
</sum>
</timelineoperation>
</derivation>
</Attribute>
<!--
The cut-off point for being entitled to benefit. Persons with
assets above this varying threshold do not qualify for benefit.
-->
<Attribute name="maximumAssetsThreshold">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Number"/>
</javaclass>
</type>
<derivation>
<!--
In a real implementation, this value would tend to vary
over time (e.g. from a rate table).
However, for the sake of example, this implementation uses
a <timelineoperation> WITHOUT a nested <intervalvalue> to
create a Timeline which has a constant value for all time.
This use of <timelineoperation> can often be useful for
dummy implementations early on in rule set development.
-->
<timelineoperation>
<!--
Hard coded forever-constant value - to be replaced by a
varying value later in rules development.
-->
<Number value="10000"/>
</timelineoperation>
</derivation>
</Attribute>
<!--
The person qualified for benefit if (on any particular day)
the person is alive and the total value of the person's assets
does not exceed the maximum asset threshold.
-->
<Attribute name="qualifiesForBenefitTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Boolean"/>
</javaclass>
</type>
<derivation>
<timelineoperation>
<all>
<fixedlist>
<listof>
<javaclass name="Boolean"/>
</listof>
<members>
<!--
operate on the Timelines as if they were primitive
values
-->
<intervalvalue>
<reference attribute="isAliveTimeline"/>
</intervalvalue>
<compare comparison="<=">
<intervalvalue>
<reference attribute="totalAssetValueTimeline"/>
</intervalvalue>
<intervalvalue>
<reference attribute="maximumAssetsThreshold"/>
</intervalvalue>
</compare>
</members>
</fixedlist>
</all>
</timelineoperation>
</derivation>
</Attribute>
</Class>
<!--
An asset, owned by a person at some time or other.
Each asset is bought, and may subsequently be sold.
The value of an asset varies over time; the asset still has a
value even before or after it is owned by a Person; however,
the _countable_ value is zero outside of the period of
ownership.
-->
<Class name="Asset">
<Attribute name="boughtDate">
<type>
<javaclass name="curam.util.type.Date"/>
</type>
<derivation>
<specified/>
</derivation>
</Attribute>
<!-- will be null if the asset has not been sold -->
<Attribute name="soldDate">
<type>
<javaclass name="curam.util.type.Date"/>
</type>
<derivation>
<specified/>
</derivation>
</Attribute>
<Attribute name="isOwnedTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Boolean"/>
</javaclass>
</type>
<derivation>
<existencetimeline>
<intervaltype>
<javaclass name="Boolean"/>
</intervaltype>
<intervalfromdate>
<reference attribute="boughtDate"/>
</intervalfromdate>
<intervaltodate>
<reference attribute="soldDate"/>
</intervaltodate>
<preExistenceValue>
<false/>
</preExistenceValue>
<existenceValue>
<true/>
</existenceValue>
<postExistenceValue>
<false/>
</postExistenceValue>
</existencetimeline>
</derivation>
</Attribute>
<!--
the varying value of the asset, regardless of whether it is
owned by the person at the time
-->
<Attribute name="valueTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Number"/>
</javaclass>
</type>
<derivation>
<specified/>
</derivation>
</Attribute>
<!--
The value which counts towards the person's assets - i.e. the
value of the asset during the period when it is owned,
otherwise 0 when it is not owned.
-->
<Attribute name="countableValueTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Number"/>
</javaclass>
</type>
<derivation>
<!--
reassemble the outputs from each <choose> invocation into a
timeline
-->
<timelineoperation>
<choose>
<type>
<javaclass name="Number"/>
</type>
<when>
<condition>
<!--
operate on each of the intervals of constant
ownership
-->
<intervalvalue>
<reference attribute="isOwnedTimeline"/>
</intervalvalue>
</condition>
<value>
<!--
if on a particular date, the asset is owned, then
its countable value on that date is simply its
value
-->
<intervalvalue>
<reference attribute="valueTimeline"/>
</intervalvalue>
</value>
</when>
<otherwise>
<value>
<!--
if on a particular date, the asset is owned, then
its countable value on that date is zero
-->
<Number value="0"/>
</value>
</otherwise>
</choose>
</timelineoperation>
</derivation>
</Attribute>
</Class>
</RuleSet>
<!--
The value which counts towards the person's assets - i.e. the
value of the asset during the period when it is owned,
otherwise 0 when it is not owned.
-->
<Attribute name="countableValueTimeline">
<type>
<javaclass name="curam.creole.value.Timeline">
<javaclass name="Number"/>
</javaclass>
</type>
<derivation>
<!--
reassemble the outputs from each <choose> invocation into a
timeline
-->
<timelineoperation>
<choose>
<type>
<javaclass name="Number"/>
</type>
<when>
<condition>
<!--
operate on each of the intervals of constant
ownership
-->
<!--
**** Forgot to wrap the Timeline returned
in <intervalvalue> ****
-->
<reference attribute="isOwnedTimeline"/>
</condition>
<value>
<!--
if on a particular date, the asset is owned, then
its countable value on that date is simply its
value
-->
<intervalvalue>
<reference attribute="valueTimeline"/>
</intervalvalue>
</value>
</when>
<otherwise>
<value>
<!--
if on a particular date, the asset is owned, then
its countable value on that date is zero
-->
<Number value="0"/>
</value>
</otherwise>
</choose>
</timelineoperation>
</derivation>
</Attribute>
ERROR ... Example_timelineoperation.xml(276, 19) AbstractRuleItem:INVALID_CHILD_RETURN_TYPE: Child 'condition' returns 'curam.creole.value.Timeline<? extends java.lang.Boolean>', but this item requires a 'java.lang.Boolean'.