Module org.apache.sis.feature
Package org.apache.sis.filter

Interface Expression<R,V>

Type Parameters:
R - the type of resources (e.g. Feature) used as inputs.
V - the type of values computed by the expression.
All Superinterfaces:
Function<R,V>
All Known Subinterfaces:
Optimization​.On­Expression<R,V>
public interface Expression<R,V> extends Function<R,V>
A literal or a named procedure that performs a distinct computation.
Upcoming API change
This is a placeholder for a GeoAPI 3.1 interface not yet released. In a future version, all usages of this interface may be replaced by an interface of the same name but in the org​.opengis​.filter package instead of org​.apache​.sis​.filter.

  • Method Summary

    Modifier and Type
    Method
    Description
    V
    apply(R input)
    Evaluates the expression value based on the content of the given object.
    Scoped­Name
    get­Function­Name()
    Returns the name of the function to be called.
    List<Expression<R,?>>
    get­Parameters()
    Returns the list sub-expressions that will be evaluated to provide the parameters to the function.
    Class<? super R>
    get­Resource­Class()
    Returns the class of resources expected by this expression.
    <N> Expression<R,N>
    to­Value­Type(Class<N> type)
    Returns an expression doing the same evaluation than this method, but returning results as values of the specified type.

    Methods inherited from interface Function

    and­Then, compose

  • Method Details

    • getFunctionName

      ScopedName getFunctionName()
      Returns the name of the function to be called.
      Returns:
      name of the function to be called.

    • getResourceClass

      Class<? super R> getResourceClass()
      Returns the class of resources expected by this expression.
      Returns:
      type of resources accepted by this expression.

    • getParameters

      List<Expression<R,?>> getParameters()
      Returns the list sub-expressions that will be evaluated to provide the parameters to the function.
      Returns:
      the sub-expressions to be evaluated, or an empty list if none.

    • apply

      V apply(R input)
      Evaluates the expression value based on the content of the given object.
      Specified by:
      apply in interface Function<R,V>
      Parameters:
      input - the object to be evaluated by the expression. Can be null if this expression allows null values.
      Returns:
      value computed by the expression.
      Throws:
      Null­Pointer­Exception - if input is null and this expression requires non-null values.
      Illegal­Argument­Exception - if the expression can not be applied on the given object.

    • toValueType

      <N> Expression<R,N> toValueType(Class<N> type)
      Returns an expression doing the same evaluation than this method, but returning results as values of the specified type.
      Type Parameters:
      N - compile-time value of type.
      Parameters:
      type - desired type of expression results.
      Returns:
      expression doing the same operation this this expression but with results of the specified type.
      Throws:
      Class­Cast­Exception - if the specified type is not a target type supported by implementation.