org.apache.commons.jelly
Class JellyContext

java.lang.Object
  org.apache.commons.jelly.JellyContext

Direct Known Subclasses:

JellyServletContext

public class JellyContext
extends java.lang.Object

JellyContext represents the Jelly context.

Version:

$Revision: 1807798 $

Author:

James Strachan

Field Summary

private boolean	allowDtdToCallExternalEntities Do we allow our doctype definitions to call out to external entities?
private static java.lang.String	BAD_PARSE String used to denote a script can't be parsed
protected java.lang.ClassLoader	classLoader The class loader to use for instantiating application objects.
private java.net.URL	currentURL The current URL context (where relative scripts are located from)
private static boolean	DEFAULT_ALLOW_DTD_CALLS_TO_EXTERNAL_ENTITIES Default for DTD calling out to external entities.
private static boolean	DEFAULT_EXPORT Default for export of variables
private static boolean	DEFAULT_INHERIT Default for inheritance of variables
private boolean	export Do we export our variables to parent context?
private boolean	exportLibraries Should we export tag libraries to our parents context
private boolean	inherit Do we inherit variables from parent context?
private static org.apache.commons.logging.Log	log The Log to which logging calls will be made.
private JellyContext	parent The parent context
private java.net.URL	rootURL The root URL context (where scripts are located from)
private java.util.Map	taglibs Tag libraries found so far
protected boolean	useContextClassLoader Do we want to use the Context ClassLoader when loading classes for instantiating new objects? Default is false.
private java.util.Map	variables synchronized access to the variables in scope

Constructor Summary

JellyContext()
Create a new context with the currentURL set to the rootURL

JellyContext(JellyContext parent)
Create a new context with the given parent context.

JellyContext(JellyContext parentJellyContext, java.net.URL currentURL)
Create a new context with the given parent context.

JellyContext(JellyContext parentJellyContext, java.net.URL rootURL, java.net.URL currentURL)
Create a new context with the given parent context.

JellyContext(java.net.URL rootURL)
Create a new context with the given rootURL

JellyContext(java.net.URL rootURL, java.net.URL currentURL)
Create a new context with the given rootURL and currentURL

Method Summary

void	clear() Clears variables set by Tags.
protected void	clearVariables() Clears variables set by Tags (variables set while running a Jelly script)
Script	compileScript(org.xml.sax.InputSource source) Attempts to parse the script from the given InputSource using the getResource(java.lang.String) method then returns the compiled script.
Script	compileScript(java.lang.String uri) Attempts to parse the script from the given uri using the getResource(java.lang.String) method then returns the compiled script.
Script	compileScript(java.net.URL url) Attempts to parse the script from the given URL using the getResource(java.lang.String) method then returns the compiled script.
protected JellyContext	createChildContext() Factory method to create a new child of this context
protected java.net.URL	createRelativeURL(java.net.URL rootURL, java.lang.String relativeURI)
protected XMLParser	createXMLParser() Factory method to allow JellyContext implementations to overload how an XMLParser is created - such as to overload what the default ExpressionFactory should be.
java.lang.Object	findVariable(java.lang.String name) Finds the variable value of the given name in this context or in any other parent context.
java.lang.ClassLoader	getClassLoader() Return the class loader to be used for instantiating application objects when required.
java.net.URL	getCurrentURL()
protected java.net.URL	getJellyContextURL(org.xml.sax.InputSource source) Strips off the name of a script to create a new context URL
protected java.net.URL	getJellyContextURL(java.net.URL url) Strips off the name of a script to create a new context URL
JellyContext	getParent()
java.net.URL	getResource(java.lang.String uri) Returns a URL for the given resource from the specified path.
java.io.InputStream	getResourceAsStream(java.lang.String uri) Attempts to open an InputStream to the given resource at the specified path.
java.net.URL	getRootURL()
JellyContext	getScope(java.lang.String name)
private java.lang.Object	getSystemProperty(java.lang.String name) Get a system property and handle security exceptions
TagLibrary	getTagLibrary(java.lang.String namespaceURI)
boolean	getUseContextClassLoader() Return the boolean as to whether the context classloader should be used.
java.lang.Object	getVariable(java.lang.String name)
java.lang.Object	getVariable(java.lang.String name, java.lang.String scopeName)
java.util.Iterator	getVariableNames()
java.util.Map	getVariables()
protected XMLParser	getXMLParser()
private void	init() Initialize the context.
boolean	isAllowDtdToCallExternalEntities()
boolean	isExport()
boolean	isExportLibraries() Returns whether we export tag libraries to our parents context
boolean	isInherit()
boolean	isTagLibraryRegistered(java.lang.String namespaceURI)
JellyContext	newJellyContext() A factory method to create a new child context of the current context.
JellyContext	newJellyContext(java.util.Map newVariables) A factory method to create a new child context of the current context.
void	registerTagLibrary(java.lang.String namespaceURI, java.lang.String className) Registers the given tag library class name against the given namespace URI.
void	registerTagLibrary(java.lang.String namespaceURI, TagLibrary taglib) Registers the given tag library against the given namespace URI.
void	removeVariable(java.lang.String name) Removes the given variable
void	removeVariable(java.lang.String name, java.lang.String scopeName) Removes the given variable in the specified scope.
JellyContext	runScript(java.io.File file, XMLOutput output) Parses the script from the given File then compiles it and runs it.
JellyContext	runScript(java.io.File file, XMLOutput output, boolean export, boolean inherit) Parses the script from the given file then compiles it and runs it.
JellyContext	runScript(org.xml.sax.InputSource source, XMLOutput output) Parses the script from the given InputSource then compiles it and runs it.
JellyContext	runScript(org.xml.sax.InputSource source, XMLOutput output, boolean export, boolean inherit) Parses the script from the given InputSource then compiles it and runs it.
JellyContext	runScript(java.lang.String uri, XMLOutput output) Parses the script from the given uri using the JellyContext.getResource() API then compiles it and runs it.
JellyContext	runScript(java.lang.String uri, XMLOutput output, boolean export, boolean inherit) Parses the script from the given uri using the JellyContext.getResource() API then compiles it and runs it.
JellyContext	runScript(java.net.URL url, XMLOutput output) Parses the script from the given URL then compiles it and runs it.
JellyContext	runScript(java.net.URL url, XMLOutput output, boolean export, boolean inherit) Parses the script from the given URL then compiles it and runs it.
void	setAllowDtdToCallExternalEntities(boolean allowDtdToCallExternalEntities) Sets whether we should allow our doctype definitions to call out to external entities.
void	setClassLoader(java.lang.ClassLoader classLoader) Set the class loader to be used for instantiating application objects when required.
void	setCurrentURL(java.net.URL currentURL) Sets the current URL context of the current script that is executing.
void	setExport(boolean export) Sets whether we should export variable definitions to our parent context
void	setExportLibraries(boolean exportLibraries) Sets whether we export tag libraries to our parents context
void	setInherit(boolean inherit) Sets whether we should inherit variables from our parent context
protected void	setParent(JellyContext context) Change the parent context to the one provided
void	setRootURL(java.net.URL rootURL) Sets the current root context URL from which all absolute resource URIs will be relative to.
void	setUseContextClassLoader(boolean use) Determine whether to use the Context ClassLoader (the one found by calling Thread.currentThread().getContextClassLoader()) to resolve/load classes.
void	setVariable(java.lang.String name, java.lang.Object value) Sets the value of the named variable
void	setVariable(java.lang.String name, java.lang.String scopeName, java.lang.Object value) Sets the value of the given variable name in the given variable scope
void	setVariables(java.util.Map variables) Sets the Map of variables to use

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

private static final org.apache.commons.logging.Log log

The Log to which logging calls will be made.

DEFAULT_INHERIT

private static final boolean DEFAULT_INHERIT

Default for inheritance of variables

See Also:

Constant Field Values

DEFAULT_EXPORT

private static final boolean DEFAULT_EXPORT

Default for export of variables

See Also:

Constant Field Values

DEFAULT_ALLOW_DTD_CALLS_TO_EXTERNAL_ENTITIES

private static final boolean DEFAULT_ALLOW_DTD_CALLS_TO_EXTERNAL_ENTITIES

Default for DTD calling out to external entities.

See Also:

Constant Field Values

BAD_PARSE

private static final java.lang.String BAD_PARSE

String used to denote a script can't be parsed

See Also:

Constant Field Values

classLoader

protected java.lang.ClassLoader classLoader

The class loader to use for instantiating application objects. If not specified, the context class loader, or the class loader used to load this class itself, is used, based on the value of the useContextClassLoader variable.

useContextClassLoader

protected boolean useContextClassLoader

Do we want to use the Context ClassLoader when loading classes for instantiating new objects? Default is false.

rootURL

private java.net.URL rootURL

The root URL context (where scripts are located from)

currentURL

private java.net.URL currentURL

The current URL context (where relative scripts are located from)

taglibs

private java.util.Map taglibs

Tag libraries found so far

variables

private java.util.Map variables

synchronized access to the variables in scope

parent

private JellyContext parent

The parent context

inherit

private boolean inherit

Do we inherit variables from parent context?

export

private boolean export

Do we export our variables to parent context?

allowDtdToCallExternalEntities

private boolean allowDtdToCallExternalEntities

Do we allow our doctype definitions to call out to external entities?

exportLibraries

private boolean exportLibraries

Should we export tag libraries to our parents context

Constructor Detail

JellyContext

public JellyContext()

Create a new context with the currentURL set to the rootURL

JellyContext

public JellyContext(java.net.URL rootURL)

Create a new context with the given rootURL

Parameters:

rootURL - the root URL used in resolving absolute resources i.e. those starting with '/'

JellyContext

public JellyContext(java.net.URL rootURL,
                    java.net.URL currentURL)

Create a new context with the given rootURL and currentURL

Parameters:

rootURL - the root URL used in resolving absolute resources i.e. those starting with '/'

currentURL - the root URL used in resolving relative resources

JellyContext

public JellyContext(JellyContext parent)

Create a new context with the given parent context. The parent's rootURL and currentURL are set on the child, and the parent's variables are available in the child context under the name parentScope.

Parameters:

parent - the parent context for the newly created context.

JellyContext

public JellyContext(JellyContext parentJellyContext,
                    java.net.URL currentURL)

Create a new context with the given parent context. The parent's rootURL are set on the child, and the parent's variables are available in the child context under the name parentScope.

Parameters:

parentJellyContext - the parent context for the newly created context.

currentURL - the root URL used in resolving relative resources

JellyContext

public JellyContext(JellyContext parentJellyContext,
                    java.net.URL rootURL,
                    java.net.URL currentURL)

Create a new context with the given parent context. The parent's variables are available in the child context under the name parentScope.

Parameters:

parentJellyContext - the parent context for the newly created context.

rootURL - the root URL used in resolving absolute resources i.e. those starting with '/'

currentURL - the root URL used in resolving relative resources

Method Detail

init

private void init()

Initialize the context. This includes adding the context to itself under the name context and making the System Properties available as systemScope

getParent

public JellyContext getParent()

Returns:

the parent context for this context

getScope

public JellyContext getScope(java.lang.String name)

Returns:

the scope of the given name, such as the 'parent' scope. If Jelly is used in a Servlet situation then 'request', 'session' and 'application' are other names for scopes

findVariable

public java.lang.Object findVariable(java.lang.String name)

Finds the variable value of the given name in this context or in any other parent context. If this context does not contain the variable, then its parent is used and then its parent and so forth until the context with no parent is found.

Returns:

the value of the variable in this or one of its descendant contexts or null if the variable could not be found.

getVariable

public java.lang.Object getVariable(java.lang.String name)

Returns:

the value of the given variable name

getSystemProperty

private java.lang.Object getSystemProperty(java.lang.String name)

Get a system property and handle security exceptions

Parameters:

name - the name of the property to retrieve

Returns:

the value of the property, or null if a SecurityException occurs

getVariable

public java.lang.Object getVariable(java.lang.String name,
                                    java.lang.String scopeName)

Parameters:

name - is the name of the variable

scopeName - is the optional scope name such as 'parent'. For servlet environments this could be 'application', 'session' or 'request'.

Returns:

the value of the given variable name in the given variable scope

setVariable

public void setVariable(java.lang.String name,
                        java.lang.Object value)

Sets the value of the named variable

setVariable

public void setVariable(java.lang.String name,
                        java.lang.String scopeName,
                        java.lang.Object value)

Sets the value of the given variable name in the given variable scope

Parameters:

name - is the name of the variable

scopeName - is the optional scope name such as 'parent'. For servlet environments this could be 'application', 'session' or 'request'.

value - is the value of the attribute

removeVariable

public void removeVariable(java.lang.String name)

Removes the given variable

removeVariable

public void removeVariable(java.lang.String name,
                           java.lang.String scopeName)

Removes the given variable in the specified scope.

Parameters:

name - is the name of the variable

scopeName - is the optional scope name such as 'parent'. For servlet environments this could be 'application', 'session' or 'request'.

getVariableNames

public java.util.Iterator getVariableNames()

Returns:

an Iterator over the current variable names in this context

getVariables

public java.util.Map getVariables()

Returns:

the Map of variables in this scope

setVariables

public void setVariables(java.util.Map variables)

Sets the Map of variables to use

newJellyContext

public JellyContext newJellyContext(java.util.Map newVariables)

A factory method to create a new child context of the current context.

newJellyContext

public JellyContext newJellyContext()

A factory method to create a new child context of the current context.

clear

public void clear()

Clears variables set by Tags.

See Also:

clearVariables()

clearVariables

protected void clearVariables()

Clears variables set by Tags (variables set while running a Jelly script)

See Also:

clear()

registerTagLibrary

public void registerTagLibrary(java.lang.String namespaceURI,
                               TagLibrary taglib)

Registers the given tag library against the given namespace URI. This should be called before the parser is used.

registerTagLibrary

public void registerTagLibrary(java.lang.String namespaceURI,
                               java.lang.String className)

Registers the given tag library class name against the given namespace URI. The class will be loaded via the given ClassLoader This should be called before the parser is used.

isTagLibraryRegistered

public boolean isTagLibraryRegistered(java.lang.String namespaceURI)

getTagLibrary

public TagLibrary getTagLibrary(java.lang.String namespaceURI)

Returns:

the TagLibrary for the given namespace URI or null if one could not be found

compileScript

public Script compileScript(java.lang.String uri)
                     throws JellyException

Attempts to parse the script from the given uri using the getResource(java.lang.String) method then returns the compiled script.

Throws:

JellyException

compileScript

public Script compileScript(java.net.URL url)
                     throws JellyException

Attempts to parse the script from the given URL using the getResource(java.lang.String) method then returns the compiled script.

Throws:

JellyException

compileScript

public Script compileScript(org.xml.sax.InputSource source)
                     throws JellyException

Attempts to parse the script from the given InputSource using the getResource(java.lang.String) method then returns the compiled script.

Throws:

JellyException

getXMLParser

protected XMLParser getXMLParser()

Returns:

a thread pooled XMLParser to avoid the startup overhead of the XMLParser

createXMLParser

protected XMLParser createXMLParser()

Factory method to allow JellyContext implementations to overload how an XMLParser is created - such as to overload what the default ExpressionFactory should be.

runScript

public JellyContext runScript(java.io.File file,
                              XMLOutput output)
                       throws JellyException

Parses the script from the given File then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(java.net.URL url,
                              XMLOutput output)
                       throws JellyException

Parses the script from the given URL then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(org.xml.sax.InputSource source,
                              XMLOutput output)
                       throws JellyException

Parses the script from the given InputSource then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(java.lang.String uri,
                              XMLOutput output)
                       throws JellyException

Parses the script from the given uri using the JellyContext.getResource() API then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(java.lang.String uri,
                              XMLOutput output,
                              boolean export,
                              boolean inherit)
                       throws JellyException

Parses the script from the given uri using the JellyContext.getResource() API then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(java.io.File file,
                              XMLOutput output,
                              boolean export,
                              boolean inherit)
                       throws JellyException

Parses the script from the given file then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(java.net.URL url,
                              XMLOutput output,
                              boolean export,
                              boolean inherit)
                       throws JellyException

Parses the script from the given URL then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

runScript

public JellyContext runScript(org.xml.sax.InputSource source,
                              XMLOutput output,
                              boolean export,
                              boolean inherit)
                       throws JellyException

Parses the script from the given InputSource then compiles it and runs it.

Returns:

the new child context that was used to run the script

Throws:

JellyException

getResource

public java.net.URL getResource(java.lang.String uri)
                         throws java.net.MalformedURLException

Returns a URL for the given resource from the specified path. If the uri starts with "/" then the path is taken as relative to the current context root. If the uri is a well formed URL then it is used. If the uri is a file that exists and can be read then it is used. Otherwise the uri is interpreted as relative to the current context (the location of the current script).

Throws:

java.net.MalformedURLException

getResourceAsStream

public java.io.InputStream getResourceAsStream(java.lang.String uri)

Attempts to open an InputStream to the given resource at the specified path. If the uri starts with "/" then the path is taken as relative to the current context root. If the uri is a well formed URL then it is used. Otherwise the uri is interpreted as relative to the current context (the location of the current script).

Returns:

null if this resource could not be loaded, otherwise the resources input stream is returned.

getRootURL

public java.net.URL getRootURL()

Returns:

the current root context URL from which all absolute resource URIs will be relative to. For example in a web application the root URL will map to the web directory which contains the WEB-INF directory.

setRootURL

public void setRootURL(java.net.URL rootURL)

Sets the current root context URL from which all absolute resource URIs will be relative to. For example in a web application the root URL will map to the web directory which contains the WEB-INF directory.

getCurrentURL

public java.net.URL getCurrentURL()

Returns:

the current URL context of the current script that is executing. This URL context is used to deduce relative scripts when relative URIs are used in calls to getResource(java.lang.String) to process relative scripts.

setCurrentURL

public void setCurrentURL(java.net.URL currentURL)

Sets the current URL context of the current script that is executing. This URL context is used to deduce relative scripts when relative URIs are used in calls to getResource(java.lang.String) to process relative scripts.

isExportLibraries

public boolean isExportLibraries()

Returns whether we export tag libraries to our parents context

Returns:

boolean

setExportLibraries

public void setExportLibraries(boolean exportLibraries)

Sets whether we export tag libraries to our parents context

Parameters:

exportLibraries - The exportLibraries to set

setExport

public void setExport(boolean export)

Sets whether we should export variable definitions to our parent context

isExport

public boolean isExport()

Returns:

whether we should export variable definitions to our parent context

setInherit

public void setInherit(boolean inherit)

Sets whether we should inherit variables from our parent context

isInherit

public boolean isInherit()

Returns:

whether we should inherit variables from our parent context

setAllowDtdToCallExternalEntities

public void setAllowDtdToCallExternalEntities(boolean allowDtdToCallExternalEntities)

Sets whether we should allow our doctype definitions to call out to external entities.

isAllowDtdToCallExternalEntities

public boolean isAllowDtdToCallExternalEntities()

Returns:

whether we should allow our doctype definitions to call out to external entities.

getClassLoader

public java.lang.ClassLoader getClassLoader()

Return the class loader to be used for instantiating application objects when required. This is determined based upon the following rules:

• The class loader set by setClassLoader(), if any
• The thread context class loader, if it exists and the useContextClassLoader property is set to true
• The class loader used to load the XMLParser class itself.

setClassLoader

public void setClassLoader(java.lang.ClassLoader classLoader)

Set the class loader to be used for instantiating application objects when required.

Parameters:

classLoader - The new class loader to use, or null to revert to the standard rules

getUseContextClassLoader

public boolean getUseContextClassLoader()

Return the boolean as to whether the context classloader should be used.

setUseContextClassLoader

public void setUseContextClassLoader(boolean use)

Determine whether to use the Context ClassLoader (the one found by calling Thread.currentThread().getContextClassLoader()) to resolve/load classes. If not using Context ClassLoader, then the class-loading defaults to using the calling-class' ClassLoader.

Parameters:

use - determines whether to use JellyContext ClassLoader.

createRelativeURL

protected java.net.URL createRelativeURL(java.net.URL rootURL,
                                         java.lang.String relativeURI)
                                  throws java.net.MalformedURLException

Parameters:

rootURL - is the root context from which the relative URI will be applied

relativeURI - is the relative URI (without a leading "/")

Returns:

a new relative URL from the given root and with the addition of the extra relative URI

Throws:

java.net.MalformedURLException - if the URL is invalid.

getJellyContextURL

protected java.net.URL getJellyContextURL(java.net.URL url)
                                   throws java.net.MalformedURLException

Strips off the name of a script to create a new context URL

Throws:

java.net.MalformedURLException

getJellyContextURL

protected java.net.URL getJellyContextURL(org.xml.sax.InputSource source)
                                   throws java.net.MalformedURLException

Strips off the name of a script to create a new context URL

Throws:

java.net.MalformedURLException

createChildContext

protected JellyContext createChildContext()

Factory method to create a new child of this context

setParent

protected void setParent(JellyContext context)

Change the parent context to the one provided

Parameters:

context - the new parent context