Package freemarker.template

Class DefaultListAdapter

java.lang.Object
freemarker.template.WrappingTemplateModel
freemarker.template.DefaultListAdapter
All Implemented Interfaces:
WrapperTemplateModel, AdapterTemplateModel, TemplateModel, TemplateModelWithAPISupport, TemplateSequenceModel, Serializable
public class DefaultListAdapter extends WrappingTemplateModel implements TemplateSequenceModel, AdapterTemplateModel, WrapperTemplateModel, TemplateModelWithAPISupport, Serializable
Adapts a List to the corresponding TemplateModel interface(s), most importantly to TemplateSequenceModel. If you aren't wrapping an already existing List, but build a sequence specifically to be used from a template, also consider using SimpleSequence (see comparison there).

Thread safety: A DefaultListAdapter is as thread-safe as the List that it wraps is. Normally you only have to consider read-only access, as the FreeMarker template language doesn't allow writing these sequences (though of course, Java methods called from the template can violate this rule).

This adapter is used by DefaultObjectWrapper if its useAdaptersForCollections property is true, which is the default when its incompatibleImprovements property is 2.3.22 or higher.

Since:
2.3.22
See Also:
SimpleSequence, DefaultArrayAdapter, TemplateSequenceModel, Serialized Form

  • Field Details

    • list

      protected final List list

  • Method Details

    • adapt

      public static DefaultListAdapter adapt​(List list, RichObjectWrapper wrapper)
      Factory method for creating new adapter instances.
      Parameters:
      list - The list to adapt; can't be null.
      wrapper - The ObjectWrapper used to wrap the items in the array.

    • get

      public TemplateModel get​(int index) throws TemplateModelException
      Description copied from interface: TemplateSequenceModel
      Retrieves the i-th template model in this sequence.
      Specified by:
      get in interface TemplateSequenceModel
      Returns:
      the item at the specified index, or null if the index is out of bounds. Note that a null value is interpreted by FreeMarker as "variable does not exist", and accessing a missing variables is usually considered as an error in the FreeMarker Template Language, so the usage of a bad index will not remain hidden, unless the default value for that case was also specified in the template.
      Throws:
      TemplateModelException

    • size

      public int size() throws TemplateModelException
      Specified by:
      size in interface TemplateSequenceModel
      Returns:
      the number of items in the list.
      Throws:
      TemplateModelException

    • getAdaptedObject

      public Object getAdaptedObject​(Class hint)
      Description copied from interface: AdapterTemplateModel
      Retrieves the underlying object, or some other object semantically equivalent to its value narrowed by the class hint.
      Specified by:
      getAdaptedObject in interface AdapterTemplateModel
      Parameters:
      hint - the desired class of the returned value. An implementation should make reasonable effort to retrieve an object of the requested class, but if that is impossible, it must at least return the underlying object as-is. As a minimal requirement, an implementation must always return the exact underlying object when hint.isInstance(underlyingObject) holds. When called with java.lang.Object.class, it should return a generic Java object (i.e. if the model is wrapping a scripting language object that is further wrapping a Java object, the deepest underlying Java object should be returned).
      Returns:
      the underlying object, or its value accommodated for the hint class.

    • getWrappedObject

      public Object getWrappedObject()
      Description copied from interface: WrapperTemplateModel
      Retrieves the original object wrapped by this model.
      Specified by:
      getWrappedObject in interface WrapperTemplateModel

    • getAPI

      public TemplateModel getAPI() throws TemplateModelException
      Description copied from interface: TemplateModelWithAPISupport
      Returns the model that exposes the (Java) API of the value. This is usually implemented by delegating to ObjectWrapperWithAPISupport.wrapAsAPI(Object).
      Specified by:
      getAPI in interface TemplateModelWithAPISupport
      Throws:
      TemplateModelException