StringResourceLoader (Apache Velocity 2.0 API)

java.lang.Object
- org.apache.velocity.runtime.resource.loader.ResourceLoader
- - org.apache.velocity.runtime.resource.loader.StringResourceLoader

Direct Known Subclasses:

VelocityScriptEngine.SingleResourceReader
```
public class StringResourceLoader
extends ResourceLoader
```
Resource loader that works with Strings. Users should manually add resources to the repository that is used by the resource loader instance. Below is an example configuration for this loader. Note that 'repository.class' is not necessary; if not provided, the factory will fall back on using StringResourceRepositoryImpl as the default.
```
 resource.loader = string
 string.resource.loader.description = Velocity StringResource loader
 string.resource.loader.class = org.apache.velocity.runtime.resource.loader.StringResourceLoader
 string.resource.loader.repository.class = org.apache.velocity.runtime.resource.loader.StringResourceRepositoryImpl
 
```
Resources can be added to the repository like this:
```
   StringResourceRepository repo = StringResourceLoader.getRepository();

   String myTemplateName = "/some/imaginary/path/hello.vm";
   String myTemplate = "Hi, ${username}... this is some template!";
   repo.putStringResource(myTemplateName, myTemplate);
 
```
After this, the templates can be retrieved as usual.

If there will be multiple StringResourceLoaders used in an application, you should consider specifying a 'string.resource.loader.repository.name = foo' property in order to keep you string resources in a non-default repository. This can help to avoid conflicts between different frameworks or components that are using StringResourceLoader. You can then retrieve your named repository like this:
```
   StringResourceRepository repo = StringResourceLoader.getRepository("foo");
 
```
and add string resources to the repo just as in the previous example.

If you have concerns about memory leaks or for whatever reason do not wish to have your string repository stored statically as a class member, then you should set 'string.resource.loader.repository.static = false' in your properties. This will tell the resource loader that the string repository should be stored in the Velocity application attributes. To retrieve the repository, do:
```
   StringResourceRepository repo = velocityEngine.getApplicationAttribute("foo");
 
```
If you did not specify a name for the repository, then it will be stored under the class name of the repository implementation class (for which the default is 'org.apache.velocity.runtime.resource.util.StringResourceRepositoryImpl'). Incidentally, this is also true for the default statically stored repository.

Whether your repository is stored statically or in Velocity's application attributes, you can also manually create and set it prior to Velocity initialization. For a static repository, you can do something like this:
```
   StringResourceRepository repo = new MyStringResourceRepository();
   repo.magicallyAddSomeStringResources();
   StringResourceLoader.setRepository("foo", repo);
 
```
Or for a non-static repository:
```
   StringResourceRepository repo = new MyStringResourceRepository();
   repo.magicallyAddSomeStringResources();
   velocityEngine.setApplicationAttribute("foo", repo);
 
```
Then, assuming the 'string.resource.loader.repository.name' property is set to 'some.name', the StringResourceLoader will use that already created repository, rather than creating a new one.
Since:

1.5

Version:

$Id: StringResourceLoader.java 1783725 2017-02-20 08:41:00Z cbrisson $

Author:

Eelco Hillenius, Henning P. Schmiedehausen, Nathan Bubna

Field Summary

Fields
Modifier and Type	Field and Description
`protected StringResourceRepository`	`repository`
`static String`	`REPOSITORY_CLASS` Key to look up the repository implementation class.
`static String`	`REPOSITORY_CLASS_DEFAULT` The default implementation class.
`static String`	`REPOSITORY_ENCODING` Key to look up the repository char encoding.
`static String`	`REPOSITORY_NAME` Key to look up the name for the repository to be used.
`static String`	`REPOSITORY_NAME_DEFAULT` The default name for string resource repositories ('org.apache.velocity.runtime.resource.util.StringResourceRepository').
`static String`	`REPOSITORY_STATIC` Key to determine whether the repository should be set as the static one or not.
`static boolean`	`REPOSITORY_STATIC_DEFAULT` By default, repositories are stored statically (shared across the VM).
`protected static Map`	`STATIC_REPOSITORIES`

Fields inherited from class org.apache.velocity.runtime.resource.loader.ResourceLoader
className, isCachingOn, log, modificationCheckInterval, rsvc

Constructor Summary

Constructors
Constructor and Description

StringResourceLoader()

Constructors
Constructor and Description
`StringResourceLoader()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`clearRepositories()` Removes all statically stored `StringResourceRepository`s.
`StringResourceRepository`	`createRepository(String className, String encoding)`
`long`	`getLastModified(Resource resource)` Get the last modified time of the InputStream source that was used to create the template.
`static StringResourceRepository`	`getRepository()` Returns a reference to the default static repository.
`static StringResourceRepository`	`getRepository(String name)` Returns a reference to the repository stored statically under the specified name.
`Reader`	`getResourceReader(String name, String encoding)` Get a reader so that the Runtime can build a template with it.
`void`	`init(ExtProperties configuration)` Initialize the template loader with a a resources class.
`boolean`	`isSourceModified(Resource resource)` Given a template, check to see if the source of InputStream has been modified.
`static StringResourceRepository`	`removeRepository(String name)` Removes the `StringResourceRepository` stored under the specified name.
`boolean`	`resourceExists(String name)` Overrides superclass for better performance.
`static void`	`setRepository(String name, StringResourceRepository repo)` Sets the specified `StringResourceRepository` in static storage under the specified name.

Methods inherited from class org.apache.velocity.runtime.resource.loader.ResourceLoader
buildReader, commonInit, getClassName, getModificationCheckInterval, isCachingOn, setCachingOn, setModificationCheckInterval

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - REPOSITORY_STATIC
```
public static final String REPOSITORY_STATIC
```
    Key to determine whether the repository should be set as the static one or not.
    
    Since:
    
    1.6
    
    See Also:
    
    Constant Field Values
  - REPOSITORY_STATIC_DEFAULT
```
public static final boolean REPOSITORY_STATIC_DEFAULT
```
    By default, repositories are stored statically (shared across the VM).
    
    Since:
    
    1.6
    
    See Also:
    
    Constant Field Values
  - REPOSITORY_CLASS
```
public static final String REPOSITORY_CLASS
```
    Key to look up the repository implementation class.
    
    See Also:
    
    Constant Field Values
  - REPOSITORY_CLASS_DEFAULT
```
public static final String REPOSITORY_CLASS_DEFAULT
```
    The default implementation class.
  - REPOSITORY_NAME
```
public static final String REPOSITORY_NAME
```
    Key to look up the name for the repository to be used.
    
    Since:
    
    1.6
    
    See Also:
    
    Constant Field Values
  - REPOSITORY_NAME_DEFAULT
```
public static final String REPOSITORY_NAME_DEFAULT
```
    The default name for string resource repositories ('org.apache.velocity.runtime.resource.util.StringResourceRepository').
    
    Since:
    
    1.6
  - REPOSITORY_ENCODING
```
public static final String REPOSITORY_ENCODING
```
    Key to look up the repository char encoding.
    
    See Also:
    
    Constant Field Values
  - STATIC_REPOSITORIES
```
protected static final Map STATIC_REPOSITORIES
```
  - repository
```
protected StringResourceRepository repository
```
- Constructor Detail
  - StringResourceLoader
```
public StringResourceLoader()
```
- Method Detail
  - getRepository
```
public static StringResourceRepository getRepository()
```
    Returns a reference to the default static repository.
  - getRepository
```
public static StringResourceRepository getRepository(String name)
```
    Returns a reference to the repository stored statically under the specified name.
    
    Since:
    
    1.6
  - setRepository
```
public static void setRepository(String name,
                                 StringResourceRepository repo)
```
    Sets the specified StringResourceRepository in static storage under the specified name.
    
    Since:
    
    1.6
  - removeRepository
```
public static StringResourceRepository removeRepository(String name)
```
    Removes the StringResourceRepository stored under the specified name.
    
    Since:
    
    1.6
  - clearRepositories
```
public static void clearRepositories()
```
    Removes all statically stored StringResourceRepositorys.
    
    Since:
    
    1.6
  - init
```
public void init(ExtProperties configuration)
```
    Description copied from class: ResourceLoader
    
    Initialize the template loader with a a resources class.
    
    Specified by:
    
    init in class ResourceLoader
    
    See Also:
    
    ResourceLoader.init(org.apache.velocity.util.ExtProperties)
  - createRepository
```
public StringResourceRepository createRepository(String className,
                                                 String encoding)
```
    Since:
    
    1.6
  - resourceExists
```
public boolean resourceExists(String name)
```
    Overrides superclass for better performance.
    
    Overrides:
    
    resourceExists in class ResourceLoader
    
    Parameters:
    
    name - The name of a resource.
    
    Returns:
    
    true if a resource exists and can be accessed.
    
    Since:
    
    1.6
  - getResourceReader
```
public Reader getResourceReader(String name,
                                String encoding)
                         throws ResourceNotFoundException
```
    Get a reader so that the Runtime can build a template with it.
    
    Specified by:
    
    getResourceReader in class ResourceLoader
    
    Parameters:
    
    name - name of template to get.
    
    encoding - asked encoding
    
    Returns:
    
    Reader containing the template.
    
    Throws:
    
    ResourceNotFoundException - Ff template not found in the RepositoryFactory.
    
    Since:
    
    2.0
  - isSourceModified
```
public boolean isSourceModified(Resource resource)
```
    Description copied from class: ResourceLoader
    
    Given a template, check to see if the source of InputStream has been modified.
    
    Specified by:
    
    isSourceModified in class ResourceLoader
    
    Returns:
    
    True if the resource has been modified.
    
    See Also:
    
    ResourceLoader.isSourceModified(org.apache.velocity.runtime.resource.Resource)
  - getLastModified
```
public long getLastModified(Resource resource)
```
    Description copied from class: ResourceLoader
    
    Get the last modified time of the InputStream source that was used to create the template. We need the template here because we have to extract the name of the template in order to locate the InputStream source.
    
    Specified by:
    
    getLastModified in class ResourceLoader
    
    Returns:
    
    Time in millis when the resource has been modified.
    
    See Also:
    
    ResourceLoader.getLastModified(org.apache.velocity.runtime.resource.Resource)

Class StringResourceLoader

Field Summary

Fields inherited from class org.apache.velocity.runtime.resource.loader.ResourceLoader

Constructor Summary

Method Summary

Methods inherited from class org.apache.velocity.runtime.resource.loader.ResourceLoader

Methods inherited from class java.lang.Object

Field Detail

REPOSITORY_STATIC

REPOSITORY_STATIC_DEFAULT

REPOSITORY_CLASS

REPOSITORY_CLASS_DEFAULT

REPOSITORY_NAME

REPOSITORY_NAME_DEFAULT

REPOSITORY_ENCODING

STATIC_REPOSITORIES

repository

Constructor Detail

StringResourceLoader

Method Detail

getRepository

getRepository

setRepository

removeRepository

clearRepositories

init

createRepository

resourceExists

getResourceReader

isSourceModified

getLastModified