org.apache.tools.ant

Class ProjectHelper

public class ProjectHelper extends Object

Configures a Project (complete with Targets and Tasks) based on a XML build file. It'll rely on a plugin to do the actual processing of the xml file. This class also provide static wrappers for common introspection. All helper plugins must provide backward compatibility with the original ant patterns, unless a different behavior is explicitly specified. For example, if namespace is used on the <project> tag the helper can expect the entire build file to be namespace-enabled. Namespaces or helper-specific tags can provide meta-information to the helper, allowing it to use new ( or different policies ). However, if no namespace is used the behavior should be exactly identical with the default helper.

Field Summary
static String	ANTLIB_URI The URI for defined types/tasks - the format is antlib:
static String	ANT_CORE_URI The URI for ant name space
static String	ANT_CURRENT_URI The URI for antlib current definitions
static String	ANT_TYPE Polymorphic attribute
static String	HELPER_PROPERTY Name of JVM system property which provides the name of the ProjectHelper class to use.
static String	PROJECTHELPER_REFERENCE name of project helper reference that we add to a project
static String	SERVICE_ID The service identifier in jars which provide Project Helper implementations.

Constructor Summary
	ProjectHelper() Default constructor

Method Summary
static BuildException	addLocationToBuildException(BuildException ex, Location newLocation) Add location to build exception.
static void	addText(Project project, Object target, char[] buf, int start, int count) Adds the content of #PCDATA sections to an element.
static void	addText(Project project, Object target, String text) Adds the content of #PCDATA sections to an element.
static void	configure(Object target, AttributeList attrs, Project project) Configures an object using an introspection handler.
static void	configureProject(Project project, File buildFile) Configures the project with the contents of the specified XML file.
static String	extractNameFromComponentName(String componentName) extract the element name from a component name
static String	extractUriFromComponentName(String componentName) extract a uri from a component name
static String	genComponentName(String uri, String name) Map a namespaced {uri,name} to an internal string format.
static ClassLoader	getContextClassLoader() JDK1.1 compatible access to the context class loader.
Vector	getImportStack() EXPERIMENTAL WILL_CHANGE Import stack.
static ProjectHelper	getProjectHelper() Discovers a project helper instance.
void	parse(Project project, Object source) Parses the project file, configuring the project as it goes.
static void	parsePropertyString(String value, Vector fragments, Vector propertyRefs) Parses a string containing `${xxx}` style property references into two lists.
static String	replaceProperties(Project project, String value) Replaces `${xxx}` style constructions in the given value with the string value of the corresponding properties.
static String	replaceProperties(Project project, String value, Hashtable keys) Replaces `${xxx}` style constructions in the given value with the string value of the corresponding data types.
static void	storeChild(Project project, Object parent, Object child, String tag) Stores a configured child element within its parent object.

Field Detail

ANTLIB_URI

public static final String ANTLIB_URI

The URI for defined types/tasks - the format is antlib:

ANT_CORE_URI

public static final String ANT_CORE_URI

The URI for ant name space

ANT_CURRENT_URI

public static final String ANT_CURRENT_URI

The URI for antlib current definitions

ANT_TYPE

public static final String ANT_TYPE

Polymorphic attribute

HELPER_PROPERTY

public static final String HELPER_PROPERTY

Name of JVM system property which provides the name of the ProjectHelper class to use.

PROJECTHELPER_REFERENCE

public static final String PROJECTHELPER_REFERENCE

name of project helper reference that we add to a project

SERVICE_ID

public static final String SERVICE_ID

The service identifier in jars which provide Project Helper implementations.

Constructor Detail

ProjectHelper

public ProjectHelper()

Default constructor

Method Detail

addLocationToBuildException

public static BuildException addLocationToBuildException(BuildException ex, Location newLocation)

Add location to build exception.

Parameters: ex the build exception, if the build exception does not include newLocation the location of the calling task (may be null)

Returns: a new build exception based in the build exception with location set to newLocation. If the original exception did not have a location, just return the build exception

addText

public static void addText(Project project, Object target, char[] buf, int start, int count)

Adds the content of #PCDATA sections to an element.

Parameters: project The project containing the target. Must not be null. target The target object to be configured. Must not be null. buf A character array of the text within the element. Will not be null. start The start element in the array. count The number of characters to read from the array.

Throws: BuildException if the target object doesn't accept text

addText

public static void addText(Project project, Object target, String text)

Adds the content of #PCDATA sections to an element.

Parameters: project The project containing the target. Must not be null. target The target object to be configured. Must not be null. text Text to add to the target. May be null, in which case this method call is a no-op.

Throws: BuildException if the target object doesn't accept text

configure

public static void configure(Object target, AttributeList attrs, Project project)

Deprecated: since 1.6.x. Use IntrospectionHelper for each property.

Configures an object using an introspection handler.

Parameters: target The target object to be configured. Must not be null. attrs A list of attributes to configure within the target. Must not be null. project The project containing the target. Must not be null.

Throws: BuildException if any of the attributes can't be handled by the target

configureProject

public static void configureProject(Project project, File buildFile)

Configures the project with the contents of the specified XML file.

Parameters: project The project to configure. Must not be null. buildFile An XML file giving the project's configuration. Must not be null.

Throws: BuildException if the configuration is invalid or cannot be read

extractNameFromComponentName

public static String extractNameFromComponentName(String componentName)

extract the element name from a component name

Parameters: componentName The stringified form for {uri, name}

Returns: The element name of the component

extractUriFromComponentName

public static String extractUriFromComponentName(String componentName)

extract a uri from a component name

Parameters: componentName The stringified form for {uri, name}

Returns: The uri or "" if not present

genComponentName

public static String genComponentName(String uri, String name)

Map a namespaced {uri,name} to an internal string format. For BC purposes the names from the ant core uri will be mapped to "name", other names will be mapped to uri + ":" + name.

Parameters: uri The namepace URI name The localname

Returns: The stringified form of the ns name

getContextClassLoader

public static ClassLoader getContextClassLoader()

Deprecated: since 1.6.x. Use LoaderUtils.getContextClassLoader()

JDK1.1 compatible access to the context class loader. Cut & paste from JAXP.

Returns: the current context class loader, or null if the context class loader is unavailable.

getImportStack

public Vector getImportStack()

EXPERIMENTAL WILL_CHANGE Import stack. Used to keep track of imported files. Error reporting should display the import path.

Returns: the stack of import source objects.

getProjectHelper

public static ProjectHelper getProjectHelper()

Discovers a project helper instance. Uses the same patterns as JAXP, commons-logging, etc: a system property, a JDK1.3 service discovery, default.

Returns: a ProjectHelper, either a custom implementation if one is available and configured, or the default implementation otherwise.

Throws: BuildException if a specified helper class cannot be loaded/instantiated.

parse

public void parse(Project project, Object source)

Parses the project file, configuring the project as it goes.

Parameters: project The project for the resulting ProjectHelper to configure. Must not be null. source The source for XML configuration. A helper must support at least File, for backward compatibility. Helpers may support URL, InputStream, etc or specialized types.

Throws: BuildException if the configuration is invalid or cannot be read

Since: Ant1.5

parsePropertyString

public static void parsePropertyString(String value, Vector fragments, Vector propertyRefs)

Deprecated: since 1.6.x. Use PropertyHelper.

Parses a string containing ${xxx} style property references into two lists. The first list is a collection of text fragments, while the other is a set of string property names. null entries in the first list indicate a property reference from the second list.

Parameters: value Text to parse. Must not be null. fragments List to add text fragments to. Must not be null. propertyRefs List to add property names to. Must not be null.

Throws: BuildException if the string contains an opening ${ without a closing }

replaceProperties

public static String replaceProperties(Project project, String value)

Deprecated: since 1.6.x. Use project.replaceProperties().

Replaces ${xxx} style constructions in the given value with the string value of the corresponding properties.

Parameters: project The project containing the properties to replace. Must not be null. value The string to be scanned for property references. May be null.

Returns: the original string with the properties replaced, or null if the original string is null.

Throws: BuildException if the string contains an opening ${ without a closing }

Since: 1.5

replaceProperties

public static String replaceProperties(Project project, String value, Hashtable keys)

Deprecated: since 1.6.x. Use PropertyHelper.

Replaces ${xxx} style constructions in the given value with the string value of the corresponding data types.

Parameters: project The container project. This is used solely for logging purposes. Must not be null. value The string to be scanned for property references. May be null, in which case this method returns immediately with no effect. keys Mapping (String to String) of property names to their values. Must not be null.

Returns: the original string with the properties replaced, or null if the original string is null.

Throws: BuildException if the string contains an opening ${ without a closing }

storeChild

public static void storeChild(Project project, Object parent, Object child, String tag)

Stores a configured child element within its parent object.

Parameters: project Project containing the objects. May be null. parent Parent object to add child to. Must not be null. child Child object to store in parent. Should not be null. tag Name of element which generated the child. May be null, in which case the child is not stored.