org.apache.velocity.runtime
Class RuntimeInstance

java.lang.Object
  extended by org.apache.velocity.runtime.RuntimeInstance
All Implemented Interfaces:
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 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();
 
 -----------------------------------------------------------------------
 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: RuntimeInstance.java 1040976 2010-12-01 12:15:39Z apetrelli $
Author:
Jason van Zyl, Jeff Bowden, Geir Magusson Jr.

Field Summary
 
Fields inherited from interface org.apache.velocity.runtime.RuntimeConstants
DEFAULT_RUNTIME_DIRECTIVES, DEFAULT_RUNTIME_PROPERTIES, DEFINE_DIRECTIVE_MAXDEPTH, ENCODING_DEFAULT, ERRORMSG_END, ERRORMSG_START, EVENTHANDLER_INCLUDE, EVENTHANDLER_INVALIDREFERENCES, EVENTHANDLER_METHODEXCEPTION, EVENTHANDLER_REFERENCEINSERTION, FILE_RESOURCE_LOADER_CACHE, FILE_RESOURCE_LOADER_PATH, INPUT_ENCODING, INTERPOLATE_STRINGLITERALS, INTROSPECTOR_RESTRICT_CLASSES, INTROSPECTOR_RESTRICT_PACKAGES, MAX_NUMBER_LOOPS, NUMBER_OF_PARSERS, OUTPUT_ENCODING, PARSE_DIRECTIVE_MAXDEPTH, PARSER_POOL_CLASS, PARSER_POOL_SIZE, PROVIDE_SCOPE_CONTROL, RESOURCE_LOADER, RESOURCE_MANAGER_CACHE_CLASS, RESOURCE_MANAGER_CLASS, RESOURCE_MANAGER_DEFAULTCACHE_SIZE, RESOURCE_MANAGER_LOGWHENFOUND, RUNTIME_LOG, RUNTIME_LOG_LOGSYSTEM, RUNTIME_LOG_LOGSYSTEM_CLASS, RUNTIME_LOG_REFERENCE_LOG_INVALID, RUNTIME_REFERENCES_STRICT, RUNTIME_REFERENCES_STRICT_ESCAPE, SKIP_INVALID_ITERATOR, STRICT_MATH, UBERSPECT_CLASSNAME, VM_ARGUMENTS_STRICT, VM_BODY_REFERENCE, VM_LIBRARY, VM_LIBRARY_AUTORELOAD, VM_LIBRARY_DEFAULT, VM_MAX_DEPTH, VM_MESSAGES_ON, VM_PERM_ALLOW_INLINE, VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL, VM_PERM_INLINE_LOCAL
 
Constructor Summary
RuntimeInstance()
          Creates a new RuntimeInstance object.
 
Method Summary
 void addDirective(Directive directive)
          Programatically add a directive.
 void addProperty(String key, Object value)
          Add a property to the configuration.
 boolean addVelocimacro(String name, Node macro, List<Macro.MacroArg> macroArgs, String sourceTemplate)
          Adds a new Velocimacro.
 void clearProperty(String key)
          Clear the values pertaining to a particular property.
 Parser createNewParser()
          Returns a JavaCC generated Parser.
 boolean dumpVMNamespace(String namespace)
          tells the vmFactory to dump the specified namespace.
 boolean evaluate(Context context, Writer writer, String logTag, Reader reader)
          Renders the input reader using the context into the output writer.
 boolean evaluate(Context context, Writer out, String logTag, String instring)
          Renders the input string using the context into the output writer.
 Object getApplicationAttribute(Object key)
          Gets the application attribute for the given key
 EventCartridge getApplicationEventCartridge()
          Returns the event handlers for the application.
 boolean getBoolean(String key, boolean def)
          Boolean property accessor method to hide the configuration implementation.
 ExtendedProperties getConfiguration()
          Return the velocity runtime configuration object.
 ContentResource getContent(String name)
          Returns a static content resource from the resource manager.
 ContentResource getContent(String name, String encoding)
          Returns a static content resource from the resource manager.
 Directive getDirective(String name)
          Retrieve a previously instantiated directive.
 int getInt(String key)
          Int property accessor method to hide the configuration implementation.
 int getInt(String key, int defaultValue)
          Int property accessor method to hide the configuration implementation.
 Introspector getIntrospector()
          Return the Introspector for this instance
 String getLoaderNameForResource(String resourceName)
          Determines if a template exists and returns name of the loader that provides it.
 Log getLog()
          Returns a convenient Log instance that wraps the current LogChute.
 Object getProperty(String key)
          Allows an external caller to get a property.
 String getString(String key)
          String property accessor method to hide the configuration implementation
 String getString(String key, String defaultValue)
          String property accessor method with default to hide the configuration implementation.
 Template getTemplate(String name)
          Returns a Template from the resource manager.
 Template getTemplate(String name, String encoding)
          Returns a Template from the resource manager
 Uberspect getUberspect()
          Returns the Uberspect object for this Instance.
 Directive getVelocimacro(String vmName, String templateName)
          Returns the appropriate VelocimacroProxy object if vmName is a valid current Velocimacro.
 Directive getVelocimacro(String vmName, String templateName, String renderingTemplate)
          Returns the appropriate VelocimacroProxy object if vmName is a valid current Velocimacro.
 List<VelocimacroProxy> getVelocimacros(String templateName)
          Return a list of VelocimacroProxies that are defined by the given template name.
 void init()
          This is the primary initialization method in the Velocity Runtime.
 void init(Properties p)
          Initialize the Velocity Runtime with a Properties object.
 void init(String configurationFile)
          Initialize the Velocity Runtime with the name of ExtendedProperties object.
 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.
 boolean isInitialized()
          Returns true if the RuntimeInstance has been successfully initialized.
 boolean isVelocimacro(String vmName, String templateName)
          Checks to see if a VM exists
 void loadDirective(String directiveClass)
          instantiates and loads the directive with some basic checks
 SimpleNode parse(Reader reader, String templateName)
          Parse the input and return the root of AST node structure.
 SimpleNode parse(Reader reader, String templateName, boolean dumpNamespace)
          Parse the input and return the root of the AST node structure.
 SimpleNode parse(String string, String templateName)
          Parse the input and return the root of AST node structure.
 void removeDirective(String name)
          Remove a directive.
 boolean render(Context context, Writer writer, String logTag, SimpleNode nodeTree)
          Initializes and renders the AST SimpleNode using the context into the output writer.
 void reset()
          Resets the instance, so Velocity can be re-initialized again.
 Object setApplicationAttribute(Object key, Object o)
          Sets the application attribute for the given key
 void setConfiguration(ExtendedProperties configuration)
          Allow an external system to set an ExtendedProperties object to use.
 void setProperties(Properties props)
          Add all the properties in props to the RuntimeInstance properties
 void setProperties(String fileName)
          Add all properties contained in the file fileName to the RuntimeInstance properties
 void setProperty(String key, Object value)
          Allows an external system to set a property in the Velocity Runtime.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

RuntimeInstance

public RuntimeInstance()
Creates a new RuntimeInstance object.

Method Detail

init

public void init()
This is the primary initialization method in the Velocity Runtime. The systems that are setup/initialized here are as follows:

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


setProperties

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


setConfiguration

public void setConfiguration(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.

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 the name of ExtendedProperties object.

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(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.

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

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

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 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

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

getVelocimacros

public List<VelocimacroProxy> getVelocimacros(String templateName)
Return a list of VelocimacroProxies that are defined by the given template name.


addVelocimacro

public boolean addVelocimacro(String name,
                              Node macro,
                              List<Macro.MacroArg> macroArgs,
                              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
macroArgs - Array of macro arguments, containing the #macro() arguments and default values. 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 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.


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