Package org.apache.tools.ant
Class IntrospectionHelper
java.lang.Object
org.apache.tools.ant.IntrospectionHelper
Helper class that collects the methods a task or nested element
 holds to set attributes, create nested elements or hold PCDATA
 elements.
 It contains hashtables containing classes that use introspection
 to handle all the invocation of the project-component specific methods.
 This class is somewhat complex, as it implements the O/X mapping between
 Ant XML and Java class instances. This is not the best place for someone new
 to Ant to start contributing to the codebase, as a change here can break the
 entire system in interesting ways. Always run a full test of Ant before checking
 in/submitting changes to this file.
 The class is final and has a private constructor.
 To get an instance for a specific (class,project) combination,
 use 
getHelper(Project,Class).
 This may return an existing version, or a new one
 ...do not make any assumptions about its uniqueness, or its validity after the Project
 instance has finished its build.- 
Nested Class SummaryNested ClassesModifier and TypeClassDescriptionstatic final classcreator - allows use of create/store external to IntrospectionHelper.
- 
Field SummaryFieldsModifier and TypeFieldDescriptionprotected static final Stringpart of the error message created bythrowNotSupported.protected static final Stringpart of the error message created bythrowNotSupported.
- 
Method SummaryModifier and TypeMethodDescriptionvoidAdds PCDATA to an element, using the element'svoid addText(String)method, if it has one.static voidClears the static cache of on build finished.createElement(Project project, Object parent, String elementName) Deprecated.since 1.6.x.Returns the addText method when the introspected class supports nested text.Returns a read-only map of attributes supported by the introspected class.getAttributeMethod(String attributeName) Returns the setter method of a named attribute.Returns an enumeration of the names of the attributes supported by the introspected class.Class<?> getAttributeType(String attributeName) Returns the type of a named attribute.getElementCreator(Project project, String parentUri, Object parent, String elementName, UnknownElement ue) returns an object that creates and stores an object for an element of a parent.getElementMethod(String elementName) Returns the adder or creator method of a named nested element.Class<?> getElementType(String elementName) Returns the type of a named nested element.Returns a read-only list of extension points supported by the introspected class.static IntrospectionHelperReturns a helper for the given class, either from the cache or by creating a new instance.static IntrospectionHelperReturns a helper for the given class, either from the cache or by creating a new instance.Returns a read-only map of nested elements supported by the introspected class.Returns an enumeration of the names of the nested elements supported by the introspected class.booleanIndicates whether the introspected class is a task container, supporting arbitrary nested tasks/types.booleanIndicates whether the introspected class is a dynamic one, supporting arbitrary nested elements and/or attributes.voidsetAttribute(Project p, Object element, String attributeName, Object value) Sets the named attribute in the given element, which is part of the given project.voidsetAttribute(Project p, Object element, String attributeName, String value) Sets the named attribute in the given element, which is part of the given project.voidstoreElement(Project project, Object parent, Object child, String elementName) Stores a named nested element using a storage method determined by the initial introspection.booleanReturns whether or not the introspected class supports PCDATA.booleansupportsNestedElement(String elementName) Indicates if this element supports a nested element of the given name.booleansupportsNestedElement(String parentUri, String elementName) Indicate if this element supports a nested element of the given name.booleansupportsNestedElement(String parentUri, String elementName, Project project, Object parent) Indicate if this element supports a nested element of the given name.booleansupportsReflectElement(String parentUri, String elementName) Check if this element supports a nested element from reflection.voidthrowNotSupported(Project project, Object parent, String elementName) Utility method to throw a NotSupported exception
- 
Field Details- 
NOT_SUPPORTED_CHILD_PREFIXpart of the error message created bythrowNotSupported.- Since:
- Ant 1.8.0
- See Also:
 
- 
NOT_SUPPORTED_CHILD_POSTFIXpart of the error message created bythrowNotSupported.- Since:
- Ant 1.8.0
- See Also:
 
 
- 
- 
Method Details- 
getHelperReturns a helper for the given class, either from the cache or by creating a new instance.- Parameters:
- c- The class for which a helper is required. Must not be- null.
- Returns:
- a helper for the specified class
 
- 
getHelperReturns a helper for the given class, either from the cache or by creating a new instance. The method will make sure the helper will be cleaned up at the end of the project, and only one instance will be created for each class.- Parameters:
- p- the project instance. Can be null, in which case the helper is not cached.
- c- The class for which a helper is required. Must not be- null.
- Returns:
- a helper for the specified class
 
- 
setAttributepublic void setAttribute(Project p, Object element, String attributeName, Object value) throws BuildException Sets the named attribute in the given element, which is part of the given project.- Parameters:
- p- The project containing the element. This is used when files need to be resolved. Must not be- null.
- element- The element to set the attribute in. Must not be- null.
- attributeName- The name of the attribute to set. Must not be- null.
- value- The value to set the attribute to. This may be interpreted or converted to the necessary type if the setter method doesn't accept an object of the supplied type.
- Throws:
- BuildException- if the introspected class doesn't support the given attribute, or if the setting method fails.
 
- 
setAttributepublic void setAttribute(Project p, Object element, String attributeName, String value) throws BuildException Sets the named attribute in the given element, which is part of the given project.- Parameters:
- p- The project containing the element. This is used when files need to be resolved. Must not be- null.
- element- The element to set the attribute in. Must not be- null.
- attributeName- The name of the attribute to set. Must not be- null.
- value- The value to set the attribute to. This may be interpreted or converted to the necessary type if the setter method doesn't just take a string. Must not be- null.
- Throws:
- BuildException- if the introspected class doesn't support the given attribute, or if the setting method fails.
 
- 
addTextAdds PCDATA to an element, using the element'svoid addText(String)method, if it has one. If no such method is present, a BuildException is thrown if the given text contains non-whitespace.- Parameters:
- project- The project which the element is part of. Must not be- null.
- element- The element to add the text to. Must not be- null.
- text- The text to add. Must not be- null.
- Throws:
- BuildException- if non-whitespace text is provided and no method is available to handle it, or if the handling method fails.
 
- 
throwNotSupportedUtility method to throw a NotSupported exception- Parameters:
- project- the Project instance.
- parent- the object which doesn't support a requested element
- elementName- the name of the Element which is trying to be created.
 
- 
createElement@Deprecated public Object createElement(Project project, Object parent, String elementName) throws BuildException Deprecated.since 1.6.x. This is not a namespace aware method.Creates a named nested element. Depending on the results of the initial introspection, either a method in the given parent instance or a simple no-arg constructor is used to create an instance of the specified element type.- Parameters:
- project- Project to which the parent object belongs. Must not be- null. If the resulting object is an instance of ProjectComponent, its Project reference is set to this parameter value.
- parent- Parent object used to create the instance. Must not be- null.
- elementName- Name of the element to create an instance of. Must not be- null.
- Returns:
- an instance of the specified element type
- Throws:
- BuildException- if no method is available to create the element instance, or if the creating method fails.
 
- 
getElementCreatorpublic IntrospectionHelper.Creator getElementCreator(Project project, String parentUri, Object parent, String elementName, UnknownElement ue) returns an object that creates and stores an object for an element of a parent.- Parameters:
- project- Project to which the parent object belongs.
- parentUri- The namespace uri of the parent object.
- parent- Parent object used to create the creator object to create and store and instance of a subelement.
- elementName- Name of the element to create an instance of.
- ue- The unknown element associated with the element.
- Returns:
- a creator object to create and store the element instance.
 
- 
isDynamicpublic boolean isDynamic()Indicates whether the introspected class is a dynamic one, supporting arbitrary nested elements and/or attributes.- Returns:
- trueif the introspected class is dynamic;- falseotherwise.
- Since:
- Ant 1.6.3
- See Also:
 
- 
isContainerpublic boolean isContainer()Indicates whether the introspected class is a task container, supporting arbitrary nested tasks/types.- Returns:
- trueif the introspected class is a container;- falseotherwise.
- Since:
- Ant 1.6.3
- See Also:
 
- 
supportsNestedElementIndicates if this element supports a nested element of the given name.- Parameters:
- elementName- the name of the nested element being checked
- Returns:
- true if the given nested element is supported
 
- 
supportsNestedElementIndicate if this element supports a nested element of the given name.Note that this method will always return true if the introspected class is dynamicor contains a method named "add" with void return type and a single argument. To ge a more thorough answer, use the four-arg version of this method instead.- Parameters:
- parentUri- the uri of the parent
- elementName- the name of the nested element being checked
- Returns:
- true if the given nested element is supported
 
- 
supportsNestedElementpublic boolean supportsNestedElement(String parentUri, String elementName, Project project, Object parent) Indicate if this element supports a nested element of the given name.Note that this method will always return true if the introspected class is dynamic, so be prepared to catch an exception about unsupported children when callinggetElementCreator.- Parameters:
- parentUri- the uri of the parent
- elementName- the name of the nested element being checked
- project- currently executing project instance
- parent- the parent element
- Returns:
- true if the given nested element is supported
- Since:
- Ant 1.8.0.
 
- 
supportsReflectElementCheck if this element supports a nested element from reflection.- Parameters:
- parentUri- the uri of the parent
- elementName- the name of the nested element being checked
- Returns:
- true if the given nested element is supported
- Since:
- Ant 1.8.0
 
- 
storeElementpublic void storeElement(Project project, Object parent, Object child, String elementName) throws BuildException Stores a named nested element using a storage method determined by the initial introspection. If no appropriate storage method is available, this method returns immediately.- Parameters:
- project- Ignored in this implementation. May be- null.
- parent- Parent instance to store the child in. Must not be- null.
- child- Child instance to store in the parent. Should not be- null.
- elementName- Name of the child element to store. May be- null, in which case this method returns immediately.
- Throws:
- BuildException- if the storage method fails.
 
- 
getElementTypeReturns the type of a named nested element.- Parameters:
- elementName- The name of the element to find the type of. Must not be- null.
- Returns:
- the type of the nested element with the specified name.
         This will never be null.
- Throws:
- BuildException- if the introspected class does not support the named nested element.
 
- 
getAttributeTypeReturns the type of a named attribute.- Parameters:
- attributeName- The name of the attribute to find the type of. Must not be- null.
- Returns:
- the type of the attribute with the specified name.
         This will never be null.
- Throws:
- BuildException- if the introspected class does not support the named attribute.
 
- 
getAddTextMethodReturns the addText method when the introspected class supports nested text.- Returns:
- the method on this introspected class that adds nested text.
         Cannot be null.
- Throws:
- BuildException- if the introspected class does not support the nested text.
- Since:
- Ant 1.6.3
 
- 
getElementMethodReturns the adder or creator method of a named nested element.- Parameters:
- elementName- The name of the attribute to find the setter method of. Must not be- null.
- Returns:
- the method on this introspected class that adds or creates this
         nested element. Can be nullwhen the introspected class is a dynamic configurator!
- Throws:
- BuildException- if the introspected class does not support the named nested element.
- Since:
- Ant 1.6.3
 
- 
getAttributeMethodReturns the setter method of a named attribute.- Parameters:
- attributeName- The name of the attribute to find the setter method of. Must not be- null.
- Returns:
- the method on this introspected class that sets this attribute.
         This will never be null.
- Throws:
- BuildException- if the introspected class does not support the named attribute.
- Since:
- Ant 1.6.3
 
- 
supportsCharacterspublic boolean supportsCharacters()Returns whether or not the introspected class supports PCDATA.- Returns:
- whether or not the introspected class supports PCDATA.
 
- 
getAttributesReturns an enumeration of the names of the attributes supported by the introspected class.- Returns:
- an enumeration of the names of the attributes supported by the introspected class.
- See Also:
 
- 
getAttributeMap
- 
getNestedElementsReturns an enumeration of the names of the nested elements supported by the introspected class.- Returns:
- an enumeration of the names of the nested elements supported by the introspected class.
- See Also:
 
- 
getNestedElementMap
- 
getExtensionPointsReturns a read-only list of extension points supported by the introspected class.A task/type or nested element with void methods named add()oraddConfigured(), taking a single class or interface argument, supports extensions point. This method returns the list of all these void add[Configured](type) methods.- Returns:
- a list of void, single argument add() or addConfigured()
         Methods of all supported extension points. These methods are sorted such that if the argument type of a method derives from another type also an argument of a method of this list, the method with the most derived argument will always appear first. Can be empty, but nevernull.
- Since:
- Ant 1.6.3
 
- 
clearCachepublic static void clearCache()Clears the static cache of on build finished.
 
-