Package org.thymeleaf.context

Class LazyContextVariable<T>

Object
org.thymeleaf.context.LazyContextVariable<T>
Type Parameters:
T - the type of the value being returned by this variable
All Implemented Interfaces:
ILazyContextVariable<T>
public abstract class LazyContextVariable<T> extends Object implements ILazyContextVariable<T>

Basic abstract implementation for the ILazyContextVariable interface.

By extending this class instead of directly implementing the ILazyContextVariable interface, users can make sure that their variables will be initialized only once (per template execution). Once its inner abstract loadValue() method is called --which implementation has to be provided by the user--, objects of this class will cache the results of such load and return these results every time the variable value is accessed.

An example: 


 context.setVariable(
     "users",
     new LazyContextVariable<List<User>>() {
         @Override
         protected List<User> loadValue() {
             return databaseRepository.findAllUsers();
         }
     });
Since:
3.0.0
Author:
Daniel Fernández

  • Constructor Details

    • LazyContextVariable

      protected LazyContextVariable()

  • Method Details

    • getValue

      public final T getValue()

      Lazily resolve the value.

      This will be transparently called by the Thymeleaf engine at template rendering time when an object of this class is resolved in a Thymeleaf expression.

      Note lazy variables will be resolved just once, and their resolved values will be reused as many times as they appear in the template.

      Specified by:
      getValue in interface ILazyContextVariable<T>
      Returns:
      the resolved value.

    • loadValue

      protected abstract T loadValue()

      Perform the actual resolution of the variable's value.

      This method will be called only once, the first time this variable is resolved.

      Returns:
      the resolved value.