Class RuntimeInstance

java.lang.Object
org.apache.velocity.runtime.RuntimeInstance
All Implemented Interfaces:
RuntimeConstants, RuntimeLogger, 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 like Turbine. Runtime properties can set and then the Runtime is initialized. Turbine, for example, knows where the templates are to be loaded from, and where the Velocity log file should be placed. So in the case of Velocity cooperating with Turbine the code might look something like the following:
 ri.setProperty(Runtime.FILE_RESOURCE_LOADER_PATH, templatePath);
 ri.setProperty(Runtime.RUNTIME_LOG, pathToVelocityLog);
 ri.init();
 
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 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
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 init()

 If init() is called by itself the RuntimeInstance will initialize
 with a set of default values.
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 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.
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Version:
$Id: RuntimeInstance.java 898050 2010-01-11 20:15:31Z nbubna $
  • Field Details

    • vmFactory

      private VelocimacroFactory vmFactory
      VelocimacroFactory object to manage VMs
    • log

      private Log log
      The Runtime logger. We start with an instance of a 'primordial logger', which just collects log messages then, when the log system is initialized, all the messages get dumpted out of the primordial one into the real one.
    • parserPool

      private ParserPool parserPool
      The Runtime parser pool
    • initializing

      private boolean initializing
      Indicate whether the Runtime is in the midst of initialization.
    • initialized

      private volatile boolean initialized
      Indicate whether the Runtime has been fully initialized.
    • overridingProperties

      private org.apache.commons.collections.ExtendedProperties overridingProperties
      These are the properties that are laid down over top of the default properties when requested.
    • runtimeDirectives

      private Map runtimeDirectives
      This is a hashtable of initialized directives. The directives that populate this hashtable are taken from the RUNTIME_DEFAULT_DIRECTIVES property file.
    • runtimeDirectivesShared

      private Map runtimeDirectivesShared
      Copy of the actual runtimeDirectives that is shared between parsers. Whenever directives are updated, the synchronized runtimeDirectives is first updated and then an unsynchronized copy of it is passed to parsers.
    • configuration

      private org.apache.commons.collections.ExtendedProperties configuration
      Object that houses the configuration options for the velocity runtime. The ExtendedProperties object allows the convenient retrieval of a subset of properties. For example all the properties for a resource loader can be retrieved from the main ExtendedProperties object using something like the following: ExtendedProperties loaderConfiguration = configuration.subset(loaderID); And a configuration is a lot more convenient to deal with then conventional properties objects, or Maps.
    • resourceManager

      private ResourceManager resourceManager
    • eventCartridge

      private EventCartridge eventCartridge
      This stores the engine-wide set of event handlers. Event handlers for each specific merge are stored in the context.
    • introspector

      private Introspector introspector
    • evaluateScopeName

      private String evaluateScopeName
    • provideEvaluateScope

      private boolean provideEvaluateScope
    • applicationAttributes

      private Map applicationAttributes
    • uberSpect

      private Uberspect uberSpect
    • encoding

      private String encoding
  • 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
    • 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
    • requireInitialization

      private void requireInitialization()
      Init or die! (with some log help, of course)
    • initializeIntrospection

      private void initializeIntrospection()
      Gets the classname for the Uberspect introspection package and instantiates an instance.
    • setDefaultProperties

      private void setDefaultProperties()
      Initializes the Velocity Runtime with properties file. The properties file may be in the file system proper, or the properties file may be in the classpath.
    • 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
    • setProperties

      public void setProperties(Properties props)
      Add all the properties in props to the RuntimeInstance properties
    • setConfiguration

      public void setConfiguration(org.apache.commons.collections.ExtendedProperties configuration)
      Allow an external system to set an ExtendedProperties object to use. This is useful where the external system also uses the ExtendedProperties class and the velocity configuration is a subset of parent application's configuration. This is the case with Turbine.
      Specified by:
      setConfiguration in interface RuntimeServices
      Parameters:
      configuration -
    • 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.
    • initializeProperties

      private void initializeProperties()
      Initialize Velocity properties, if the default properties have not been laid down first then do so. Then proceed to process any overriding properties. Laying down the default properties gives a much greater chance of having a working system.
    • 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
    • setProperties

      private void setProperties(org.apache.commons.collections.ExtendedProperties p)
    • init

      public void init(String configurationFile)
      Initialize the Velocity Runtime with the name of ExtendedProperties object.
      Specified by:
      init in interface RuntimeServices
      Parameters:
      configurationFile -
    • initializeResourceManager

      private void initializeResourceManager()
    • initializeEventHandlers

      private void initializeEventHandlers()
    • initializeSpecificEventHandler

      private EventHandler initializeSpecificEventHandler(String classname, String paramName, Class EventHandlerInterface)
    • initializeLog

      private void initializeLog()
      Initialize the Velocity logging system.
    • initializeDirectives

      private void initializeDirectives()
      This methods initializes all the directives that are used by the Velocity Runtime. The directives to be initialized are listed in the RUNTIME_DEFAULT_DIRECTIVES properties file.
    • 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.
    • updateSharedDirectivesMap

      private void updateSharedDirectivesMap()
      Makes an unsynchronized copy of the directives map that is used for Directive lookups by all parsers. This follows Copy-on-Write pattern. The cost of creating a new map is acceptable since directives are typically set and modified only during Velocity setup phase.
    • loadDirective

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

      private void initializeParserPool()
      Initializes the Velocity parser pool.
    • createNewParser

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

      public SimpleNode parse(String string, String templateName) 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:
      string - String to be parsed
      templateName - name of the template being parsed
      Returns:
      A root node representing the template as an AST tree.
      Throws:
      ParseException - When the string could not be parsed as a template.
      Since:
      1.6
    • parse

      public SimpleNode parse(Reader reader, String templateName) 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
      templateName - name of the template being parsed
      Returns:
      A root node representing the template as an AST tree.
      Throws:
      ParseException - When the template could not be parsed.
    • parse

      public SimpleNode parse(Reader reader, String templateName, boolean dumpNamespace) throws ParseException
      Parse the input and return the root of the AST node structure.
      Specified by:
      parse in interface RuntimeServices
      Parameters:
      reader - Reader retrieved by a resource loader
      templateName - name of the template being parsed
      dumpNamespace - flag to dump the Velocimacro namespace for this template
      Returns:
      A root node representing the template as an AST tree.
      Throws:
      ParseException - When the template could not be parsed.
    • initializeEvaluateScopeSettings

      private void initializeEvaluateScopeSettings()
    • 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.
      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.
      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.
      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.
      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
    • getDefaultEncoding

      private String getDefaultEncoding()
      Retrieves and caches the configured default encoding for better performance. (VELOCITY-606)
    • 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 input.encoding property. The default is "ISO-8859-1"
      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

      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 Log getLog()
      Returns a convenient Log instance that wraps the current LogChute. Use this to log error messages. It has the usual methods.
      Specified by:
      getLog in interface RuntimeServices
      Returns:
      A convenience Log instance that wraps the current LogChute.
      Since:
      1.5
    • warn

      public void warn(Object message)
      Deprecated.
      Use getLog() and call warn() on it.
      Specified by:
      warn in interface RuntimeLogger
      Parameters:
      message - The message to log.
      See Also:
    • info

      public void info(Object message)
      Deprecated.
      Use getLog() and call info() on it.
      Specified by:
      info in interface RuntimeLogger
      Parameters:
      message - The message to log.
      See Also:
    • error

      public void error(Object message)
      Deprecated.
      Use getLog() and call error() on it.
      Specified by:
      error in interface RuntimeLogger
      Parameters:
      message - The message to log.
      See Also:
    • debug

      public void debug(Object message)
      Deprecated.
      Use getLog() and call debug() on it.
      Specified by:
      debug in interface RuntimeLogger
      Parameters:
      message - The message to log.
      See Also:
    • 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, String templateName)
      Returns the appropriate VelocimacroProxy object if vmName is a valid current Velocimacro.
      Specified by:
      getVelocimacro in interface RuntimeServices
      Parameters:
      vmName - Name of velocimacro requested
      templateName - Name of the template that contains the velocimacro.
      Returns:
      The requested VelocimacroProxy.
      Since:
      1.6
    • getVelocimacro

      public Directive getVelocimacro(String vmName, String templateName, String renderingTemplate)
      Returns the appropriate VelocimacroProxy object if vmName is a valid current Velocimacro.
      Specified by:
      getVelocimacro in interface RuntimeServices
      Parameters:
      vmName - Name of velocimacro requested
      templateName - Name of the namespace.
      renderingTemplate - Name of the 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.
      Returns:
      VelocimacroProxy
      Since:
      Velocity 1.6
    • addVelocimacro

      public boolean addVelocimacro(String name, String macro, String[] argArray, String sourceTemplate)
      Deprecated.
      Use addVelocimacro(String, Node, String[], String) instead
      Adds a new Velocimacro. Usually called by Macro only while parsing.
      Specified by:
      addVelocimacro in interface RuntimeServices
      Parameters:
      name - Name of velocimacro
      macro - String form of macro body
      argArray - Array of strings, containing the #macro() arguments. the 0th is the name.
      sourceTemplate - Name of the template that contains the velocimacro.
      Returns:
      True if added, false if rejected for some reason (either parameters or permission settings)
    • addVelocimacro

      public boolean addVelocimacro(String name, Node macro, String[] argArray, String sourceTemplate)
      Adds a new Velocimacro. Usually called by Macro only while parsing. Called by org.apache.velocity.runtime.directive.processAndRegister
      Specified by:
      addVelocimacro in interface RuntimeServices
      Parameters:
      name - Name of velocimacro
      macro - root AST node of the parsed macro
      argArray - Array of strings, containing the #macro() arguments. the 0th is the name.
      sourceTemplate -
      Returns:
      boolean True if added, false if rejected for some reason (either parameters or permission settings)
      Since:
      Velocity 1.6
    • isVelocimacro

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

      public boolean dumpVMNamespace(String namespace)
      tells the vmFactory to dump the specified namespace. This is to support clearing the VM list when in inline-VM-local-scope mode
      Specified by:
      dumpVMNamespace in interface RuntimeServices
      Parameters:
      namespace - Namespace to dump.
      Returns:
      True if namespace was dumped successfully.
    • 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 org.apache.commons.collections.ExtendedProperties getConfiguration()
      Return the velocity runtime configuration object.
      Specified by:
      getConfiguration in interface RuntimeServices
      Returns:
      Configuration object which houses the Velocity runtime properties.
    • getIntrospector

      public Introspector getIntrospector()
      Return the Introspector for this instance
      Specified by:
      getIntrospector in interface RuntimeServices
      Returns:
      The Introspector for this instance
    • 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.