Package net.shibboleth.shared.spring.velocity

Class VelocityEngineFactory

java.lang.Object
net.shibboleth.shared.spring.velocity.VelocityEngineFactory
Direct Known Subclasses:
VelocityConfigurer, VelocityEngineFactoryBean
public class VelocityEngineFactory extends Object
Factory that configures a VelocityEngine. Can be used standalone, but typically you will either use VelocityEngineFactoryBean for preparing a VelocityEngine as bean reference, or VelocityConfigurer for web views.

The optional "configLocation" property sets the location of the Velocity properties file, within the current application. Velocity properties can be overridden via "velocityProperties", or even completely specified locally, avoiding the need for an external properties file.

The "resourceLoaderPath" property can be used to specify the Velocity resource loader path via Spring's Resource abstraction, possibly relative to the Spring application context.

The simplest way to use this class is to specify a "resourceLoaderPath"; the VelocityEngine typically then does not need any further configuration.

Since:
6.0.0
See Also:

  • Field Details

    • log

      @Nonnull private final org.slf4j.Logger log
      Class logger.

    • configLocation

      @Nullable private Resource configLocation
      Source of configuration.

    • velocityProperties

      @Nonnull @NullableElements private final Map<String,Object> velocityProperties
      Configuration properties.

    • resourceLoaderPath

      @Nullable private String resourceLoaderPath
      Path to load resources from.

    • resourceLoader

      @Nullable private ResourceLoader resourceLoader
      Resource loader.

    • preferFileSystemAccess

      private boolean preferFileSystemAccess
      Whether to favor file system lookup first.

  • Constructor Details

    • VelocityEngineFactory

      public VelocityEngineFactory()
      Constructor.

  • Method Details

    • setConfigLocation

      public void setConfigLocation(@Nullable Resource location)
      Set the location of the Velocity config file.

      Alternatively, you can specify all properties locally.

      Parameters:
      location - configuration resource
      See Also:

    • setVelocityProperties

      public void setVelocityProperties(@Nullable Properties props)
      Set Velocity properties, like "file.resource.loader.path".

      Can be used to override values in a Velocity config file, or to specify all necessary properties locally.

      Note that the Velocity resource loader path also be set to any Spring resource location via the "resourceLoaderPath" property. Setting it here is just necessary when using a non-file-based resource loader.

      Parameters:
      props - additional properties
      See Also:

    • setVelocityPropertiesMap

      public void setVelocityPropertiesMap(@Nullable @NullableElements Map<String,Object> map)
      Set Velocity properties as Map, to allow for non-String values like "ds.resource.loader.instance".
      Parameters:
      map - properties as map
      See Also:

    • setResourceLoaderPath

      public void setResourceLoaderPath(@Nullable String paths)
      Set the Velocity resource loader path via a Spring resource location.

      Accepts multiple locations in Velocity's comma-separated path style.

      When populated via a String, standard URLs like "file:" and "classpath:" pseudo URLs are supported, as understood by ResourceLoader. Allows for relative paths when running in an ApplicationContext.

      Will define a path for the default Velocity resource loader with the name "file". If the specified resource cannot be resolved to a java.io.File, a generic SpringResourceLoader will be used under the name "spring", without modification detection.

      Note that resource caching will be enabled in any case. With the file resource loader, the last-modified timestamp will be checked on access to detect changes. With SpringResourceLoader, the resource will be cached forever (for example for class path resources).

      To specify a modification check interval for files, use Velocity's standard "file.resource.loader.modificationCheckInterval" property. By default, the file timestamp is checked on every access (which is surprisingly fast). Of course, this just applies when loading resources from the file system.

      To enforce the use of SpringResourceLoader, i.e. to not resolve a path as file system resource in any case, turn off the "preferFileSystemAccess" flag. See the latter's javadoc for details.

      Parameters:
      paths - comma-separated paths
      See Also:

    • setResourceLoader

      public void setResourceLoader(@Nullable ResourceLoader loader)
      Set the Spring ResourceLoader to use for loading Velocity template files.

      The default is DefaultResourceLoader. Will get overridden by the ApplicationContext if running in a context.

      Parameters:
      loader - resource loader
      See Also:

    • setPreferFileSystemAccess

      public void setPreferFileSystemAccess(boolean flag)
      Set whether to prefer file system access for template loading.

      File system access enables hot detection of template changes.

      If this is enabled, VelocityEngineFactory will try to resolve the specified "resourceLoaderPath" as file system resource (which will work for expanded class path resources and ServletContext resources too).

      Default is "true". Turn this off to always load via SpringResourceLoader (i.e. as stream, without hot detection of template changes), which might be necessary if some of your templates reside in an expanded classes directory while others reside in jar files.

      Parameters:
      flag - flag to set
      See Also:

    • createVelocityEngine

      @Nonnull public org.apache.velocity.app.VelocityEngine createVelocityEngine() throws IOException, org.apache.velocity.exception.VelocityException
      Prepare the VelocityEngine instance and return it.
      Returns:
      the VelocityEngine instance
      Throws:
      IOException - if the config file wasn't found
      org.apache.velocity.exception.VelocityException - on Velocity initialization failure

    • newVelocityEngine

      @Nonnull protected org.apache.velocity.app.VelocityEngine newVelocityEngine() throws IOException, org.apache.velocity.exception.VelocityException
      Return a new VelocityEngine.

      Subclasses can override this for custom initialization, or for using a mock object for testing.

      Called by createVelocityEngine().

      Returns:
      the VelocityEngine instance
      Throws:
      IOException - if a config file wasn't found
      org.apache.velocity.exception.VelocityException - on Velocity initialization failure
      See Also:

    • initVelocityResourceLoader

      protected void initVelocityResourceLoader(@Nonnull org.apache.velocity.app.VelocityEngine velocityEngine, @Nullable String loaderPath)
      Initialize a Velocity resource loader for the given VelocityEngine: either a standard Velocity FileResourceLoader or a SpringResourceLoader.
      Parameters:
      velocityEngine - the VelocityEngine to configure
      loaderPath - the path to load Velocity resources from
      See Also:

    • initSpringResourceLoader

      protected void initSpringResourceLoader(@Nonnull org.apache.velocity.app.VelocityEngine velocityEngine, @Nullable String path)
      Initialize a SpringResourceLoader for the given VelocityEngine.

      Called by initVelocityResourceLoader.

      Parameters:
      velocityEngine - the VelocityEngine to configure
      path - the path to load Velocity resources from
      See Also:

    • postProcessVelocityEngine

      protected void postProcessVelocityEngine(@Nonnull org.apache.velocity.app.VelocityEngine velocityEngine) throws IOException, org.apache.velocity.exception.VelocityException
      To be implemented by subclasses that want to perform custom post-processing of the VelocityEngine after the FactoryBean performed its default configuration (but before VelocityEngine.init).
      Parameters:
      velocityEngine - the current VelocityEngine
      Throws:
      IOException - if a config file wasn't found
      org.apache.velocity.exception.VelocityException - on Velocity initialization failure
      See Also: