freemarker.template
Class RootModelWrapper

java.lang.Object
  freemarker.template.RootModelWrapper

All Implemented Interfaces:

TemplateHashModel, TemplateModel, TemplateModelRoot, TemplateWriteableHashModel, java.io.Serializable

public class RootModelWrapper
extends java.lang.Object
implements TemplateModelRoot, java.io.Serializable

Wraps a template hash model with a template model root. The hash model can be accessed transparently from the root of this model. Any local variables are stored within a HashMap. Anything that doesn't exist within the HashMap is automatically forwarded to the wrapped hash model. Local variables are counted as being any variables added using the put() method.

Use this class when your template model (the hash model) is shared across several template calls, possibly multithreaded, and you want to be sure that the model isn't inadvertently changed between calls.

To do this for multithreaded calls, create a separate RootModelWrapper object for each template call, passing in the data model you want to be left unchanged. Then, call your templates with each RootModelWrapper object as your root data model.

To do this for synchronous calls, it is sufficient to create one RootModelWrapper object, passing in the data model you want to be left unchanged. Then, call your templates with the RootModelWrapper object as your root data model, and call the reset() method between each template call.

This class was previously in the freemarker.ext.misc package.

Since:

1.8

Version:

$Id: RootModelWrapper.java 1153 2013-04-15 10:59:37Z run2000 $

See Also:

LocalModelWrapper, Serialized Form

Field Summary

protected TemplateHashModel	hashModel The underlying template hash being wrapped.
protected java.util.Map<java.lang.String,TemplateModel>	rootModel The map containing temporary values for the root model.

Constructor Summary

RootModelWrapper(TemplateHashModel innerModel)
Create a new RootModelWrapper with the given hash model as the model to be wrapped.

RootModelWrapper(TemplateHashModel innerModel, java.util.Map<java.lang.String,TemplateModel> modelMap)
Create a new RootModelWrapper with the given hash model as the model to be wrapped.

Method Summary

TemplateModel	get(java.lang.String key) Retrieve a template model for the given key, if one exists.
boolean	isEmpty() Returns whether we have a completely empty model.
void	put(java.lang.String key, TemplateModel model) Put the given template model into local storage with the given key.
void	remove(java.lang.String key) Remove the named model from local storage.
void	reset() Clear all the local variables from the local storage, and just provide pass-through access to the wrapped hash model.
java.lang.String	toString() Returns a string representation of the object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

rootModel

protected java.util.Map<java.lang.String,TemplateModel> rootModel

The map containing temporary values for the root model.

hashModel

protected TemplateHashModel hashModel

The underlying template hash being wrapped.

Constructor Detail

RootModelWrapper

public RootModelWrapper(TemplateHashModel innerModel)

Create a new RootModelWrapper with the given hash model as the model to be wrapped.

Parameters:

innerModel - the hash model to be wrapped

RootModelWrapper

public RootModelWrapper(TemplateHashModel innerModel,
                        java.util.Map<java.lang.String,TemplateModel> modelMap)

Create a new RootModelWrapper with the given hash model as the model to be wrapped.

Parameters:

innerModel - the hash model to be wrapped

modelMap - the map containing the outer model

Method Detail

get

public TemplateModel get(java.lang.String key)
                  throws TemplateModelException

Retrieve a template model for the given key, if one exists. First, look at the local storage to see if we have an entry. If so, return the local entry. Otherwise, forward the call to the wrapped hash model.

Specified by:

get in interface TemplateHashModel

Parameters:

key - the name of the value to be returned

Returns:

a TemplateModel for the corresponding key, if one exists, otherwise null

Throws:

TemplateModelException - there was a problem with the underlying hash model

isEmpty

public boolean isEmpty()
                throws TemplateModelException

Returns whether we have a completely empty model. If the local storage is non-empty, return false. Otherwise, forward the call to the wrapped hash model.

Specified by:

isEmpty in interface TemplateModel

Returns:

true if the model is empty, otherwise false

Throws:

TemplateModelException - there was a problem with underlying hash model

put

public void put(java.lang.String key,
                TemplateModel model)

Put the given template model into local storage with the given key.

Specified by:

put in interface TemplateModelRoot

Specified by:

put in interface TemplateWriteableHashModel

Parameters:

key - the name of the model to be stored

model - the model being stored locally

remove

public void remove(java.lang.String key)

Remove the named model from local storage.

Note that we don't attempt to block access to the hash model when we remove a key. This is because the only time a "remove" call is performed is when the template engine is sure that there was no underlying data for that key to begin with.

Specified by:

remove in interface TemplateModelRoot

Parameters:

key - the name of the model to be removed

reset

public void reset()

Clear all the local variables from the local storage, and just provide pass-through access to the wrapped hash model.

toString

public java.lang.String toString()

Returns a string representation of the object.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the object.