org.apache.velocity.runtime

Class RuntimeInstance

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,v 1.19.4.1 2004/03/03 23:22:55 geirm Exp $

Author: Jason van Zyl Jeff Bowden Geir Magusson Jr.

Field Summary
MapapplicationAttributes
ExtendedPropertiesconfiguration
Object that houses the configuration options for the velocity runtime.
booleaninitialized
Indicate whether the Runtime has been fully initialized.
Introspectorintrospector
LogSystemlogSystem
The Runtime logger.
ExtendedPropertiesoverridingProperties
These are the properties that are laid down over top of the default properties when requested.
SimplePoolparserPool
The Runtime parser pool
ResourceManagerresourceManager
HashtableruntimeDirectives
This is a hashtable of initialized directives.
UberspectuberSpect
VelocimacroFactoryvmFactory
VelocimacroFactory object to manage VMs
Constructor Summary
RuntimeInstance()
Method Summary
voidaddProperty(String key, Object value)
Add a property to the configuration.
booleanaddVelocimacro(String name, String macro, String[] argArray, String sourceTemplate)
Adds a new Velocimacro.
voidclearProperty(String key)
Clear the values pertaining to a particular property.
ParsercreateNewParser()
Returns a JavaCC generated Parser.
voiddebug(Object message)
Log a debug message.
booleandumpVMNamespace(String namespace)
tells the vmFactory to dump the specified namespace.
voiderror(Object message)
Log an error message.
ObjectgetApplicationAttribute(Object key)
booleangetBoolean(String key, boolean def)
Boolean property accessor method to hide the configuration implementation.
ExtendedPropertiesgetConfiguration()
Return the velocity runtime configuration object.
ContentResourcegetContent(String name)
Returns a static content resource from the resource manager.
ContentResourcegetContent(String name, String encoding)
Returns a static content resource from the resource manager.
intgetInt(String key)
Int property accessor method to hide the configuration implementation.
intgetInt(String key, int defaultValue)
Int property accessor method to hide the configuration implementation.
IntrospectorgetIntrospector()
Return the Introspector for this instance
StringgetLoaderNameForResource(String resourceName)
Determines is a template exists, and returns name of the loader that provides it.
ObjectgetProperty(String key)
Allows an external caller to get a property.
StringgetString(String key, String defaultValue)
String property accessor method with default to hide the configuration implementation.
StringgetString(String key)
String property accessor method to hide the configuration implementation
TemplategetTemplate(String name)
Returns a Template from the resource manager.
TemplategetTemplate(String name, String encoding)
Returns a Template from the resource manager
UberspectgetUberspect()
DirectivegetVelocimacro(String vmName, String templateName)
Returns the appropriate VelocimacroProxy object if strVMname is a valid current Velocimacro.
voidinfo(Object message)
Log an info message.
voidinit()
voidinit(Properties p)
Initialize the Velocity Runtime with a Properties object.
voidinit(String configurationFile)
Initialize the Velocity Runtime with the name of ExtendedProperties object.
voidinitializeDirectives()
This methods initializes all the directives that are used by the Velocity Runtime.
voidinitializeIntrospection()
Gets the classname for the Uberspect introspection package and instantiates an instance.
voidinitializeLogger()
Initialize the Velocity logging system.
voidinitializeParserPool()
Initializes the Velocity parser pool.
voidinitializeProperties()
Initialize Velocity properties, if the default properties have not been laid down first then do so.
voidinitializeResourceManager()
booleanisVelocimacro(String vmName, String templateName)
Checks to see if a VM exists
voidloadDirective(String directiveClass, String caption)
instantiates and loads the directive with some basic checks
voidlog(int level, Object message)
Handle logging.
SimpleNodeparse(Reader reader, String templateName)
Parse the input and return the root of AST node structure.
SimpleNodeparse(Reader reader, String templateName, boolean dumpNamespace)
Parse the input and return the root of the AST node structure.
ObjectsetApplicationAttribute(Object key, Object o)
voidsetConfiguration(ExtendedProperties configuration)
Allow an external system to set an ExtendedProperties object to use.
voidsetDefaultProperties()
Initializes the Velocity Runtime with properties file.
voidsetProperty(String key, Object value)
Allows an external system to set a property in the Velocity Runtime.
booleanshowStackTrace()
Added this to check and make sure that the configuration is initialized before trying to get properties from it.
voidwarn(Object message)
Log a warning message.

Field Detail

applicationAttributes

private Map applicationAttributes

configuration

private 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.

initialized

private boolean initialized
Indicate whether the Runtime has been fully initialized.

introspector

private Introspector introspector

logSystem

private LogSystem logSystem
The Runtime logger. We start with an instance of a 'primordial logger', which just collects log messages then, when the log system is initialized, we dump all messages out of the primordial one into the real one.

overridingProperties

private ExtendedProperties overridingProperties
These are the properties that are laid down over top of the default properties when requested.

parserPool

private SimplePool parserPool
The Runtime parser pool

resourceManager

private ResourceManager resourceManager

runtimeDirectives

private Hashtable runtimeDirectives
This is a hashtable of initialized directives. The directives that populate this hashtable are taken from the RUNTIME_DEFAULT_DIRECTIVES property file. This hashtable is passed to each parser that is created.

uberSpect

private Uberspect uberSpect

vmFactory

private VelocimacroFactory vmFactory
VelocimacroFactory object to manage VMs

Constructor Detail

RuntimeInstance

public RuntimeInstance()

Method Detail

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"]

Parameters: String key String value

addVelocimacro

public boolean addVelocimacro(String name, String macro, String[] argArray, String sourceTemplate)
Adds a new Velocimacro. Usually called by Macro only while parsing.

Parameters: String name Name of velocimacro String macro String form of macro body String argArray Array of strings, containing the #macro() arguments. the 0th is the name.

Returns: boolean True if added, false if rejected for some reason (either parameters or permission settings)

clearProperty

public void clearProperty(String key)
Clear the values pertaining to a particular property.

Parameters: String key of property to clear

createNewParser

public Parser createNewParser()
Returns a JavaCC generated Parser.

Returns: Parser javacc generated parser

debug

public void debug(Object message)
Log a debug message.

Parameters: Object message to log

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

error

public void error(Object message)
Log an error message.

Parameters: Object message to log

getApplicationAttribute

public Object getApplicationAttribute(Object key)

getBoolean

public boolean getBoolean(String key, boolean def)
Boolean property accessor method to hide the configuration implementation.

Parameters: String key property key boolean default default value if property not found

Returns: boolean value of key or default value

getConfiguration

public ExtendedProperties getConfiguration()
Return the velocity runtime configuration object.

Returns: ExtendedProperties configuration object which houses the velocity runtime properties.

getContent

public ContentResource getContent(String name)
Returns a static content resource from the resource manager. Uses the current value if INPUT_ENCODING as the character encoding.

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.

getContent

public ContentResource getContent(String name, String encoding)
Returns a static content resource from the resource manager.

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.

getInt

public int getInt(String key)
Int property accessor method to hide the configuration implementation.

Parameters: String key property key

Returns: int value

getInt

public int getInt(String key, int defaultValue)
Int property accessor method to hide the configuration implementation.

Parameters: key property key int default value

Returns: int value

getIntrospector

public Introspector getIntrospector()
Return the Introspector for this instance

getLoaderNameForResource

public String getLoaderNameForResource(String resourceName)
Determines is a template exists, and returns name of the loader that provides it. This is a slightly less hokey way to support the Velocity.templateExists() utility method, which was broken when per-template encoding was introduced. We can revisit this.

Parameters: resourceName Name of template or content resource

Returns: class name of loader than can provide it

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.

Parameters: key property to return

getString

public String getString(String key, String defaultValue)
String property accessor method with default to hide the configuration implementation.

Parameters: String key property key String defaultValue default value to return if key not found in resource manager.

Returns: String value of key or default

getString

public String getString(String key)
String property accessor method to hide the configuration implementation

Parameters: key property key

Returns: value of key or null

getTemplate

public Template getTemplate(String name)
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"

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. Exception if an error occurs in template initialization

getTemplate

public Template getTemplate(String name, String encoding)
Returns a Template from the resource manager

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. Exception if an error occurs in template initialization

getUberspect

public Uberspect getUberspect()

getVelocimacro

public Directive getVelocimacro(String vmName, String templateName)
Returns the appropriate VelocimacroProxy object if strVMname is a valid current Velocimacro.

Parameters: String vmName Name of velocimacro requested

Returns: String VelocimacroProxy

info

public void info(Object message)
Log an info message.

Parameters: Object message to log

init

public void init()

init

public void init(Properties p)
Initialize the Velocity Runtime with a Properties object.

Parameters: Properties

init

public void init(String configurationFile)
Initialize the Velocity Runtime with the name of ExtendedProperties object.

Parameters: Properties

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.

Throws: Exception

initializeIntrospection

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

initializeLogger

private void initializeLogger()
Initialize the Velocity logging system.

Throws: Exception

initializeParserPool

private void initializeParserPool()
Initializes the Velocity parser pool. This still needs to be implemented.

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.

initializeResourceManager

private void initializeResourceManager()

isVelocimacro

public boolean isVelocimacro(String vmName, String templateName)
Checks to see if a VM exists

Parameters: name Name of velocimacro

Returns: boolean True if VM by that name exists, false if not

loadDirective

private void loadDirective(String directiveClass, String caption)
instantiates and loads the directive with some basic checks

Parameters: directiveClass classname of directive to load

log

private void log(int level, Object message)
Handle logging.

Parameters: String message to log

parse

public SimpleNode parse(Reader reader, String templateName)
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.

Parameters: InputStream inputstream retrieved by a resource loader String name of the template being parsed

parse

public SimpleNode parse(Reader reader, String templateName, boolean dumpNamespace)
Parse the input and return the root of the AST node structure.

Parameters: InputStream inputstream retrieved by a resource loader String name of the template being parsed dumpNamespace flag to dump the Velocimacro namespace for this template

setApplicationAttribute

public Object setApplicationAttribute(Object key, Object o)

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.

Parameters: ExtendedProperties configuration

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.

Parameters: String property key String property value

showStackTrace

private boolean showStackTrace()
Added this to check and make sure that the configuration is initialized before trying to get properties from it. This occurs when there are errors during initialization and the default properties have yet to be layed down.

warn

public void warn(Object message)
Log a warning message.

Parameters: Object message to log

Copyright B) 2002 Apache Software Foundation. All Rights Reserved.