PersistentFieldBundle (Tapestry API - 5.7.2)乐学网一站式学习平台

All Known Implementing Classes:

PersistentFieldBundleImpl
```
public interface PersistentFieldBundle
```
Encapsulates persisted property information for an entire page.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`containsValue(String componentId, String fieldName)`	Checks to see if a persistent value has been stored for the indicated component and field.
`Object`	`getValue(String componentId, String fieldName)`

- Method Detail
  - containsValue
```
boolean containsValue(String componentId,
                      String fieldName)
```
    Checks to see if a persistent value has been stored for the indicated component and field. TODO: This method can probably be removed; it doesn't look like its used (instead, we if check getValue() returns null).
    
    Parameters:
    
    componentId - the nested id of the component (within the page), may be null or blank for the root component of the page
    
    fieldName - the name of the field whose value was persisted
    
    Returns:
    
    true if a change has been stored
  - getValue
```
Object getValue(String componentId,
                String fieldName)
```
    Parameters:
    
    componentId - the nested if of the component (within the page), may be null or blank for the root component of the page
    
    fieldName - the name of the field whose value was persisted
    
    Returns:
    
    the persisted value, possibly null