Package com.inductiveautomation.ignition.common.expressions

Class ConstantExpression

java.lang.Object
com.inductiveautomation.ignition.common.expressions.ConstantExpression
All Implemented Interfaces:
Expression
public class ConstantExpression extends Object implements Expression

  • Constructor Details

    • ConstantExpression

      public ConstantExpression(Object value)

    • ConstantExpression

      public ConstantExpression(Object value, QualityCode quality)

    • ConstantExpression

      public ConstantExpression()

  • Method Details

    • execute

      public @NonNull QualifiedValue execute()
      Description copied from interface: Expression
      Compute and return the value of this expression.
      Specified by:
      execute in interface Expression
      Returns:
      the result of the expression evaluation as a QualifiedValue

    • getType

      public Class<?> getType()
      Description copied from interface: Expression
      Return the type that this expression will return.
      Specified by:
      getType in interface Expression
      Returns:
      the Class of the value returned by Expression.execute()

    • getOpName

      public String getOpName()
      Description copied from interface: Expression
      Return a human-readable name for the operation that this expression performs.
      Specified by:
      getOpName in interface Expression
      Returns:
      the operation name

    • getChildren

      public Expression[] getChildren()
      Description copied from interface: Expression
      The children (if any) that this expression is dependent on for its execution.
      Specified by:
      getChildren in interface Expression
      Returns:
      an array of child Expressions, or an empty array if no children exist

    • getValue

      public Object getValue()

    • setValue

      public void setValue(Object object)

    • getQuality

      public QualityCode getQuality()

    • setQuality

      public void setQuality(QualityCode quality)

    • connect

      public void connect(CommonContext context, InteractionListener updateListener)
      Description copied from interface: Expression
      Gives the expression a chance to connect itself to things, if necessary. Most expressions do not have any connections. An expression should notify the updateListener if they change.
      Specified by:
      connect in interface Expression
      Parameters:
      context - the CommonContext used to look up external resources
      updateListener - the InteractionListener to notify when the expression value changes

    • disconnect

      public void disconnect()
      Description copied from interface: Expression
      Tells the expression to disconnect from anything it was connected to.
      Specified by:
      disconnect in interface Expression

    • shutdown

      public void shutdown()
      Description copied from interface: Expression
      Tells the expression to shutdown any polling operations.
      Specified by:
      shutdown in interface Expression

    • startup

      public void startup()
      Description copied from interface: Expression
      Tells the expression to startup any polling operations. Expressions that use this can remember the updateListener from connect() to feed update notification to.
      Specified by:
      startup in interface Expression