Package org.apache.velocity.runtime

Class RuntimeInstance

java.lang.Object
org.apache.velocity.runtime.RuntimeInstance
All Implemented Interfaces:
DeprecatedRuntimeConstants, RuntimeConstants, RuntimeServices
public class RuntimeInstance extends Object implements RuntimeConstants, RuntimeServices

This is the Runtime system for Velocity. It is the single access point for all functionality in Velocity. It adheres to the mediator pattern and is the only structure that developers need to be familiar with in order to get Velocity to perform.

The Runtime will also cooperate with external systems, which can make all needed setProperty() calls before calling init().

 -----------------------------------------------------------------------
 N O T E S  O N  R U N T I M E  I N I T I A L I Z A T I O N
 -----------------------------------------------------------------------
 init()

 If init() is called by itself the RuntimeInstance will initialize
 with a set of default values.
 -----------------------------------------------------------------------
 init(String/Properties)

 In this case the default velocity properties are layed down
 first to provide a solid base, then any properties provided
 in the given properties object will override the corresponding
 default property.
 -----------------------------------------------------------------------
Version:
$Id$
Author:
Jason van Zyl, Jeff Bowden, Geir Magusson Jr.

  • Constructor Details

    • RuntimeInstance

      public RuntimeInstance()
      Creates a new RuntimeInstance object.

  • Method Details

    • init

      public void init()
      This is the primary initialization method in the Velocity Runtime. The systems that are setup/initialized here are as follows:
      • Logging System
      • ResourceManager
      • EventHandler
      • Parser Pool
      • Global Cache
      • Static Content Include System
      • Velocimacro System
      Specified by:
      init in interface RuntimeServices

    • reset

      public void reset()
      Resets the instance, so Velocity can be re-initialized again.
      Since:
      2.0.0

    • isInitialized

      public boolean isInitialized()
      Returns true if the RuntimeInstance has been successfully initialized.
      Specified by:
      isInitialized in interface RuntimeServices
      Returns:
      True if the RuntimeInstance has been successfully initialized.
      Since:
      1.5

    • setProperty

      public void setProperty(String key, Object value)
      Allows an external system to set a property in the Velocity Runtime.
      Specified by:
      setProperty in interface RuntimeServices
      Parameters:
      key - property key
      value - property value

    • setProperties

      public void setProperties(String fileName)
      Add all properties contained in the file fileName to the RuntimeInstance properties
      Parameters:
      fileName -

    • setProperties

      public void setProperties(Properties props)
      Add all the properties in props to the RuntimeInstance properties
      Parameters:
      props -

    • setConfiguration

      public void setConfiguration(ExtProperties configuration)
      Allow an external system to set an ExtProperties object to use.
      Specified by:
      setConfiguration in interface RuntimeServices
      Parameters:
      configuration -
      Since:
      2.0

    • addProperty

      public void addProperty(String key, Object value)
      Add a property to the configuration. If it already exists then the value stated here will be added to the configuration entry. For example, if resource.loader = file is already present in the configuration and you addProperty("resource.loader", "classpath") Then you will end up with a Vector like the following: ["file", "classpath"]
      Specified by:
      addProperty in interface RuntimeServices
      Parameters:
      key -
      value -

    • clearProperty

      public void clearProperty(String key)
      Clear the values pertaining to a particular property.
      Specified by:
      clearProperty in interface RuntimeServices
      Parameters:
      key - of property to clear

    • getProperty

      public Object getProperty(String key)
      Allows an external caller to get a property. The calling routine is required to know the type, as this routine will return an Object, as that is what properties can be.
      Specified by:
      getProperty in interface RuntimeServices
      Parameters:
      key - property to return
      Returns:
      Value of the property or null if it does not exist.

    • init

      public void init(Properties p)
      Initialize the Velocity Runtime with a Properties object.
      Specified by:
      init in interface RuntimeServices
      Parameters:
      p - Velocity properties for initialization

    • init

      public void init(String configurationFile)
      Initialize the Velocity Runtime with a properties file path.
      Specified by:
      init in interface RuntimeServices
      Parameters:
      configurationFile -

    • addDirective

      public void addDirective(Directive directive)
      Programatically add a directive.
      Parameters:
      directive -

    • getDirective

      public Directive getDirective(String name)
      Retrieve a previously instantiated directive.
      Specified by:
      getDirective in interface RuntimeServices
      Parameters:
      name - name of the directive
      Returns:
      the Directive for that name

    • removeDirective

      public void removeDirective(String name)
      Remove a directive.
      Parameters:
      name - name of the directive.

    • loadDirective

      public void loadDirective(String directiveClass)
      instantiates and loads the directive with some basic checks
      Parameters:
      directiveClass - classname of directive to load

    • createNewParser

      public Parser createNewParser()
      Returns a JavaCC generated Parser.
      Specified by:
      createNewParser in interface RuntimeServices
      Returns:
      Parser javacc generated parser

    • parse

      public SimpleNode parse(Reader reader, Template template) throws ParseException
      Parse the input and return the root of AST node structure.

      In the event that it runs out of parsers in the pool, it will create and let them be GC'd dynamically, logging that it has to do that. This is considered an exceptional condition. It is expected that the user will set the PARSER_POOL_SIZE property appropriately for their application. We will revisit this.
      Specified by:
      parse in interface RuntimeServices
      Parameters:
      reader - Reader retrieved by a resource loader
      template - template being parsed
      Returns:
      A root node representing the template as an AST tree.
      Throws:
      ParseException - When the template could not be parsed.

    • evaluate

      public boolean evaluate(Context context, Writer out, String logTag, String instring)
      Renders the input string using the context into the output writer. To be used when a template is dynamically constructed, or want to use Velocity as a token replacer.
      Note! Macros defined in evaluate() calls are not persisted in memory so next evaluate() call does not know about macros defined during previous calls.
      Specified by:
      evaluate in interface RuntimeServices
      Parameters:
      context - context to use in rendering input string
      out - Writer in which to render the output
      logTag - string to be used as the template name for log messages in case of error
      instring - input string containing the VTL to be rendered
      Returns:
      true if successful, false otherwise. If false, see Velocity runtime log
      Throws:
      ParseErrorException - The template could not be parsed.
      MethodInvocationException - A method on a context object could not be invoked.
      ResourceNotFoundException - A referenced resource could not be loaded.
      Since:
      Velocity 1.6

    • evaluate

      public boolean evaluate(Context context, Writer writer, String logTag, Reader reader)
      Renders the input reader using the context into the output writer. To be used when a template is dynamically constructed, or want to use Velocity as a token replacer.
      Note! Macros defined in evaluate() calls are not persisted in memory so next evaluate() call does not know about macros defined during previous calls.
      Specified by:
      evaluate in interface RuntimeServices
      Parameters:
      context - context to use in rendering input string
      writer - Writer in which to render the output
      logTag - string to be used as the template name for log messages in case of error
      reader - Reader containing the VTL to be rendered
      Returns:
      true if successful, false otherwise. If false, see Velocity runtime log
      Throws:
      ParseErrorException - The template could not be parsed.
      MethodInvocationException - A method on a context object could not be invoked.
      ResourceNotFoundException - A referenced resource could not be loaded.
      Since:
      Velocity 1.6

    • render

      public boolean render(Context context, Writer writer, String logTag, SimpleNode nodeTree)

      Initializes and renders the AST SimpleNode using the context into the output writer.

      Note that the nodeTree argument should be a fresh AST tree obtained by the parse(Reader, Template) method.

      If you wish to reuse AST trees but bypass the resource loading mechanism, you should rely on the Template API, as follow:

      
      RuntimeInstance runtimeInstance = new RuntimeInstance();
      Template template = new Template();
      template.setName("my_template");
      template.setRuntimeServices(runtimeInstance);
      SimpleNode astTree = runtimeInstance.parse(new StringReader("Some template..."), template);
      template.setData(astTree);
      template.initDocument();

      You will then be able to render several times the template with template.render(context, writer).

      Parameters:
      context - context to use in rendering input string
      writer - Writer in which to render the output
      logTag - string to be used as the template name for log messages in case of error
      nodeTree - SimpleNode which is the root of the AST to be rendered
      Returns:
      true if successful, false otherwise. If false, see Velocity runtime log for errors
      Throws:
      ParseErrorException - The template could not be parsed.
      MethodInvocationException - A method on a context object could not be invoked.
      ResourceNotFoundException - A referenced resource could not be loaded.
      Since:
      Velocity 1.6

    • invokeVelocimacro

      public boolean invokeVelocimacro(String vmName, String logTag, String[] params, Context context, Writer writer)
      Invokes a currently registered Velocimacro with the params provided and places the rendered stream into the writer.
      Note: currently only accepts args to the VM if they are in the context.
      Note: only macros in the global context can be called. This method doesn't find macros defined by templates during previous mergeTemplate calls if Velocity.VM_PERM_INLINE_LOCAL has been enabled.
      Specified by:
      invokeVelocimacro in interface RuntimeServices
      Parameters:
      vmName - name of Velocimacro to call
      logTag - string to be used for template name in case of error. if null, the vmName will be used
      params - keys for args used to invoke Velocimacro, in java format rather than VTL (eg "foo" or "bar" rather than "$foo" or "$bar")
      context - Context object containing data/objects used for rendering.
      writer - Writer for output stream
      Returns:
      true if Velocimacro exists and successfully invoked, false otherwise.
      Since:
      1.6

    • getTemplate

      public Template getTemplate(String name) throws ResourceNotFoundException, ParseErrorException
      Returns a Template from the resource manager. This method assumes that the character encoding of the template is set by the resource.default_encoding property. The default is UTF-8.
      Specified by:
      getTemplate in interface RuntimeServices
      Parameters:
      name - The file name of the desired template.
      Returns:
      The template.
      Throws:
      ResourceNotFoundException - if template not found from any available source.
      ParseErrorException - if template cannot be parsed due to syntax (or other) error.

    • getTemplate

      public Template getTemplate(String name, String encoding) throws ResourceNotFoundException, ParseErrorException
      Returns a Template from the resource manager
      Specified by:
      getTemplate in interface RuntimeServices
      Parameters:
      name - The name of the desired template.
      encoding - Character encoding of the template
      Returns:
      The template.
      Throws:
      ResourceNotFoundException - if template not found from any available source.
      ParseErrorException - if template cannot be parsed due to syntax (or other) error.

    • getContent

      public ContentResource getContent(String name) throws ResourceNotFoundException, ParseErrorException
      Returns a static content resource from the resource manager. Uses the current value if INPUT_ENCODING as the character encoding.
      Specified by:
      getContent in interface RuntimeServices
      Parameters:
      name - Name of content resource to get
      Returns:
      parsed ContentResource object ready for use
      Throws:
      ResourceNotFoundException - if template not found from any available source.
      ParseErrorException - When the template could not be parsed.

    • getContent

      public ContentResource getContent(String name, String encoding) throws ResourceNotFoundException, ParseErrorException
      Returns a static content resource from the resource manager.
      Specified by:
      getContent in interface RuntimeServices
      Parameters:
      name - Name of content resource to get
      encoding - Character encoding to use
      Returns:
      parsed ContentResource object ready for use
      Throws:
      ResourceNotFoundException - if template not found from any available source.
      ParseErrorException - When the template could not be parsed.

    • getLoaderNameForResource

      public String getLoaderNameForResource(String resourceName)
      Determines if a template exists and returns name of the loader that provides it. This is a slightly less hokey way to support the Velocity.resourceExists() utility method, which was broken when per-template encoding was introduced. We can revisit this.
      Specified by:
      getLoaderNameForResource in interface RuntimeServices
      Parameters:
      resourceName - Name of template or content resource
      Returns:
      class name of loader than can provide it

    • getLog

      public org.slf4j.Logger getLog()
      Returns the configured logger.
      Specified by:
      getLog in interface RuntimeServices
      Returns:
      A Logger instance
      Since:
      1.5

    • getLog

      public org.slf4j.Logger getLog(String childNamespace)
      Get a logger for the specified child namespace. If a logger was configured using the runtime.log.instance configuration property, returns this instance. Otherwise, uses SLF4J LoggerFactory on baseNamespace '.' childNamespace.
      Specified by:
      getLog in interface RuntimeServices
      Parameters:
      childNamespace -
      Returns:
      child namespace logger

    • getLogContext

      public LogContext getLogContext()
      Get the LogContext object used to tack locations in templates.
      Specified by:
      getLogContext in interface RuntimeServices
      Returns:
      LogContext object
      Since:
      2.2

    • getString

      public String getString(String key, String defaultValue)
      String property accessor method with default to hide the configuration implementation.
      Specified by:
      getString in interface RuntimeServices
      Parameters:
      key - property key
      defaultValue - default value to return if key not found in resource manager.
      Returns:
      value of key or default

    • getVelocimacro

      public Directive getVelocimacro(String vmName, Template renderingTemplate, Template template)
      Returns the appropriate VelocimacroProxy object if vmName is a valid current Velocimacro.
      Specified by:
      getVelocimacro in interface RuntimeServices
      Parameters:
      vmName - Name of velocimacro requested
      renderingTemplate - Template we are currently rendering. This information is needed when VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL setting is true and template contains a macro with the same name as the global macro library.
      template - Template which acts as the host for the macro
      Returns:
      VelocimacroProxy

    • addVelocimacro

      public boolean addVelocimacro(String name, Node macro, List<Macro.MacroArg> macroArgs, Template definingTemplate)
      Adds a new Velocimacro. Usually called by Macro only while parsing.
      Specified by:
      addVelocimacro in interface RuntimeServices
      Parameters:
      name - Name of velocimacro
      macro - root AST node of the parsed macro
      macroArgs - Array of macro arguments, containing the #macro() arguments and default values. the 0th is the name.
      definingTemplate - Template containing the source of the macro
      Returns:
      boolean True if added, false if rejected for some reason (either parameters or permission settings)

    • isVelocimacro

      public boolean isVelocimacro(String vmName, Template template)
      Checks to see if a VM exists
      Specified by:
      isVelocimacro in interface RuntimeServices
      Parameters:
      vmName - Name of the Velocimacro.
      template - Template on which to look for the Macro.
      Returns:
      True if VM by that name exists, false if not

    • getString

      public String getString(String key)
      String property accessor method to hide the configuration implementation
      Specified by:
      getString in interface RuntimeServices
      Parameters:
      key - property key
      Returns:
      value of key or null

    • getInt

      public int getInt(String key)
      Int property accessor method to hide the configuration implementation.
      Specified by:
      getInt in interface RuntimeServices
      Parameters:
      key - Property key
      Returns:
      value

    • getInt

      public int getInt(String key, int defaultValue)
      Int property accessor method to hide the configuration implementation.
      Specified by:
      getInt in interface RuntimeServices
      Parameters:
      key - property key
      defaultValue - The default value.
      Returns:
      value

    • getBoolean

      public boolean getBoolean(String key, boolean def)
      Boolean property accessor method to hide the configuration implementation.
      Specified by:
      getBoolean in interface RuntimeServices
      Parameters:
      key - property key
      def - The default value if property not found.
      Returns:
      value of key or default value

    • getConfiguration

      public ExtProperties getConfiguration()
      Return the velocity runtime configuration object.
      Specified by:
      getConfiguration in interface RuntimeServices
      Returns:
      Configuration object which houses the Velocity runtime properties.

    • getApplicationEventCartridge

      public EventCartridge getApplicationEventCartridge()
      Returns the event handlers for the application.
      Specified by:
      getApplicationEventCartridge in interface RuntimeServices
      Returns:
      The event handlers for the application.
      Since:
      1.5

    • getApplicationAttribute

      public Object getApplicationAttribute(Object key)
      Gets the application attribute for the given key
      Specified by:
      getApplicationAttribute in interface RuntimeServices
      Parameters:
      key -
      Returns:
      The application attribute for the given key.

    • setApplicationAttribute

      public Object setApplicationAttribute(Object key, Object o)
      Sets the application attribute for the given key
      Specified by:
      setApplicationAttribute in interface RuntimeServices
      Parameters:
      key -
      o - The new application attribute.
      Returns:
      The old value of this attribute or null if it hasn't been set before.

    • getUberspect

      public Uberspect getUberspect()
      Returns the Uberspect object for this Instance.
      Specified by:
      getUberspect in interface RuntimeServices
      Returns:
      The Uberspect object for this Instance.

    • useStringInterning

      public boolean useStringInterning()
      Whether to use string interning
      Specified by:
      useStringInterning in interface RuntimeServices
      Returns:
      boolean

    • getSpaceGobbling

      public RuntimeConstants.SpaceGobbling getSpaceGobbling()
      get space gobbling mode
      Specified by:
      getSpaceGobbling in interface RuntimeServices
      Returns:
      indentation mode

    • isHyphenAllowedInIdentifiers

      public boolean isHyphenAllowedInIdentifiers()
      get whether hyphens are allowed in identifiers
      Specified by:
      isHyphenAllowedInIdentifiers in interface RuntimeServices
      Returns:
      configured boolean flag

    • isScopeControlEnabled

      public boolean isScopeControlEnabled(String scopeName)
      Get whether to provide a scope control object for this scope
      Specified by:
      isScopeControlEnabled in interface RuntimeServices
      Parameters:
      scopeName -
      Returns:
      scope control enabled
      Since:
      2.1

    • getParserConfiguration

      public ParserConfiguration getParserConfiguration()
      Description copied from interface: RuntimeServices
      Get the replacement characters configured for this runtime service's parser
      Specified by:
      getParserConfiguration in interface RuntimeServices
      Returns:
      configured replacement characters