StringExpression (JMRI API)

All Superinterfaces:

Base, PropertyChangeProvider

All Known Subinterfaces:

FemaleStringExpressionSocket, MaleStringExpressionSocket, StringExpressionBean

All Known Implementing Classes:

AbstractStringExpression, DebuggerMaleStringExpressionSocket, DefaultFemaleStringExpressionSocket, DefaultMaleStringExpressionSocket, StringExpressionConstant, StringExpressionMemory, StringFormula
```
public interface StringExpression
extends Base
```
String expression is used in LogixNG to answer a question that can give a string value as result.

Nested Class Summary
- Nested classes/interfaces inherited from interface jmri.jmrit.logixng.Base
  Base.PrintTreeSettings, Base.RunnableWithBase, Base.RunnableWithBaseThrowException

Field Summary
- Fields inherited from interface jmri.jmrit.logixng.Base
  PRINT_LINE_NUMBERS_FORMAT, PROPERTY_CHILD_COUNT, PROPERTY_CHILD_REORDER, PROPERTY_LAST_RESULT_CHANGED, PROPERTY_SOCKET_CONNECTED, PROPERTY_SOCKET_DISCONNECTED, SEPARATOR, SOCKET_CONNECTED, SOCKET_DISCONNECTED

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.lang.String`	`evaluate()`	Evaluate this expression.
`boolean`	`getTriggerOnChange()`	Get whenether this expression should trigger the ConditionalNG if the named beans it listens to changes state.
`void`	`setTriggerOnChange(boolean triggerOnChange)`	Set whenether this expression should trigger the ConditionalNG if the named beans it listens to changes state.

Methods inherited from interface jmri.jmrit.logixng.Base
addPropertyChangeListener, addPropertyChangeListener, deepCopyChildren, dispose, doSocketOperation, existsInTree, forEntireTree, forEntireTreeWithException, getCategory, getChild, getChildCount, getComment, getConditionalNG, getDeepCopy, getListenerRef, getListenerRefs, getListenerRefsIncludingChildren, getLogixNG, getLongDescription, getLongDescription, getModule, getNumPropertyChangeListeners, getParent, getPropertyChangeListenersByReference, getRoot, getShortDescription, getShortDescription, getSystemName, getUsageDetail, getUsageTree, getUserName, hasChild, isActive, isEnabled, isSocketOperationAllowed, printTree, printTree, printTree, printTree, printTree, registerListeners, setComment, setParent, setParentForAllChildren, setup, setUserName, unregisterListeners, updateListenerRef, vetoableChange

Methods inherited from interface jmri.beans.PropertyChangeProvider
addPropertyChangeListener, addPropertyChangeListener, getPropertyChangeListeners, getPropertyChangeListeners, removePropertyChangeListener, removePropertyChangeListener

- Method Detail
  - evaluate
```
java.lang.String evaluate()
                   throws JmriException
```
    Evaluate this expression.
    
    Returns:
    
    the result of the evaluation
    
    Throws:
    
    JmriException - when an exception occurs
  - setTriggerOnChange
```
void setTriggerOnChange(boolean triggerOnChange)
```
    Set whenether this expression should trigger the ConditionalNG if the named beans it listens to changes state.
    
    Parameters:
    
    triggerOnChange - true if trigger on change, false otherwise
  - getTriggerOnChange
```
boolean getTriggerOnChange()
```
    Get whenether this expression should trigger the ConditionalNG if the named beans it listens to changes state.
    
    Returns:
    
    true if trigger on change, false otherwise