# Package org.eclipse.jface.text.templates

Application programming interfaces for interaction with the Eclipse text template support.

## Templates

### Packages

- `org.eclipse.jface.text.templates`
- `org.eclipse.ui.workbench.texteditor.templates`
- `org.eclipse.ui.editors.templates`

### Introduction

Templates are shortcuts for frequently used fragments of text such as code patterns or complex text entities. They may contain variables which are only resolved at the time when the template is inserted within a context. Together with linked mode, inserting a template can create a on-the-fly edit mask within a text viewer.
Templates are specified as text, variables are defined using the `${variable}` notation known from Ant, for example. The following snippet shows an example template for an instance check in Java:

    if (${name} instanceof ${type}) {
        ${type} ${new_name} = (${type})${name};
        ${cursor}
    }

In this template, the variables (`name,type, ...`) are resolved when inserted into java source and changing one variable instance will also change the other. When leaving linked mode, the caret is placed at the `cursor` variable.
Template functionality can be added to a custom text editor by offering `TemplateProposal`s as content assist choices, which is simplified by using a subclass of `TemplateCompletionProcessor`. User template management can be offered by including a `TemplatePreferencePage` which uses a `TemplateStore` and `ContextTypeRegistry` as the underlying model to store templates. The `org.eclipse.ui.editors.templates` extension point can be used to allow other plug-ins to contribute templates to an editor. This is accomplished by using the `ContributionTemplateStore` and `ContributionContextTypeRegistry` subclasses of the above types.
Template variables are resolved by a `TemplateVariableResolver.` `GlobalTemplateVariables` offers some default variables such as date, user, and selection, but advanced features such as resolving to language constructs can be performed in subclasses.

#### Classes

- `Template` a template consists of name, context type identifier, and a pattern.
- `TemplateTranslator` and `TemplateBuffer` are used to parse the template grammar and don't need to be used usually.
- A `TemplateProposal` can be offered in content assist, possibly created by a subclass of `TemplateCompletionProcessor.`
- `TemplateStore` and `ContextTypeRegistry` manage a set of templates within a plug-in and offer ways to store them in the preferences or externally in XML streams via a `TemplateReaderWriter`.
- `ContributionTemplateStore` and `ContributionContextTypeRegistry` add awareness for the `org.eclipse.ui.editors.templates` extension point.
- `TemplatePreferencePage` allows the user to access the templates within a `TemplateStore.`

#### Example

See the Template Editor Example in the org.eclipse.ui.examples.javaeditor project.

Class Summary
ContextTypeRegistry: Deprecated. See `ContextTypeRegistry`
DocumentTemplateContext: Instances of this class describe the context of a template as a region of a document.
GlobalTemplateVariables: Global variables which are available in any context.
GlobalTemplateVariables.Cursor: The cursor variable determines the cursor placement after template edition.
GlobalTemplateVariables.Date: The date variable evaluates to the current date.
GlobalTemplateVariables.Dollar: The dollar variable inserts an escaped dollar symbol.
GlobalTemplateVariables.LineSelection: The line selection variable determines templates that work on selected lines.
GlobalTemplateVariables.Selection: The selection variable determines templates that work on a selection.
GlobalTemplateVariables.Time: The time variable evaluates to the current time.
GlobalTemplateVariables.User: The user variable evaluates to the current user.
GlobalTemplateVariables.WordSelection: The word selection variable determines templates that work on selected words, but not on selected lines.
GlobalTemplateVariables.Year: The year variable evaluates to the current year.
SimpleTemplateVariableResolver: A simple template variable resolver, which always evaluates to a defined string.
Template: A template consisting of a name and a pattern.
TemplateBuffer: A template buffer is a container for a string and variables.
TemplateCompletionProcessor: A completion processor that computes template proposals.
TemplateContext: Provides the context for a `Template` being resolved.
TemplateContextType: A context type defines a context within which templates are resolved.
TemplateProposal: A template completion proposal.
TemplateTranslator: The template translator translates a string into a template buffer.
TemplateVariable: A `TemplateVariable` represents a set of positions into a `TemplateBuffer` with identical content each.
TemplateVariableResolver: A `TemplateVariableResolver` resolves `TemplateVariables` of a certain type inside a `TemplateContext`.
TemplateVariableType: Value object that represents the type of a template variable.

Exception Summary
TemplateException: Thrown when a template cannot be validated.