public interface EPType extends Serializable
EPType
is the common superinterface for all types in EPL.
The EPL compiler and runtime do not use Class
as Java type erasure means that a class instance
does not provide information about its type parameters. For instance the type List<String>
has String
as the type parameter. Looking at List.class
alone
does not provide such type information.
Further, EPL (and modern SQL) has Three-Valued Logic (3VL), wherein the null
-value
returns a value of type null. Java does not have a representation for the type null.
EPL allows null-typed columns, such as in create schema MyEvent(emptyColumn null)
.
EPL allows null to occur in the select-clause, as exemplified in select null as item from OrderEvent
.
The null-type is represented by EPTypeNull
. All other types are represented by EPTypeClass
or
EPTypeClassParameterized
. This allows the EPL compiler and runtime to track null-type
and parameterized types.
Modifier and Type | Method and Description |
---|---|
String |
getTypeName()
Returns the type name.
|
String getTypeName()
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