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ProjectHelper (Apache Ant API)

org.apache.tools.ant
Class ProjectHelper


java.lang.Object

  |

  +--org.apache.tools.ant.ProjectHelper

Direct Known Subclasses:
ProjectHelperImpl

public class ProjectHelper
extends java.lang.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 This class also provide static wrappers for common introspection. All helper plugins must provide backward compatiblity with the original ant patterns, unless a different behavior is explicitely 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.

Author:
duncan@x180.com

Field Summary
static java.lang.String HELPER_PROPERTY
          Name of JVM system property which provides the name of the ProjectHelper class to use.
static java.lang.String SERVICE_ID
          The service identifier in jars which provide Project Helper implementations.
 
Constructor Summary
ProjectHelper()
          Default constructor
  Project project)
          Configures an object using an introspection handler.
Method Summary
static void addText(Project project, java.lang.Object target, char[] buf, int start, int count)
          Adds the content of #PCDATA sections to an element.
static void addText(Project project, java.lang.Object target, java.lang.String text)
          Adds the content of #PCDATA sections to an element.
static void
static void configureProject(Project project, java.io.File buildFile)
          Configures the project with the contents of the specified XML file.
static java.lang.ClassLoader getContextClassLoader()
          JDK1.1 compatible access to the context class loader.
static ProjectHelper getProjectHelper()
          Discovers a project helper instance.
 void parse(Project project, java.lang.Object source)
          Parses the project file, configuring the project as it goes.
static void parsePropertyString(java.lang.String value, java.util.Vector fragments, java.util.Vector propertyRefs)
          Parses a string containing ${xxx} style property references into two lists.
static java.lang.String replaceProperties(Project project, java.lang.String value)
          Replaces ${xxx} style constructions in the given value with the string value of the corresponding properties.
static java.lang.String replaceProperties(Project project, java.lang.String value, java.util.Hashtable keys)
          Replaces ${xxx} style constructions in the given value with the string value of the corresponding data types.
static void storeChild(Project project, java.lang.Object parent, java.lang.Object child, java.lang.String tag)
          Stores a configured child element within its parent object.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

HELPER_PROPERTY


public static final java.lang.String HELPER_PROPERTY
Name of JVM system property which provides the name of the ProjectHelper class to use.

See Also:
Constant Field Values

SERVICE_ID


public static final java.lang.String SERVICE_ID
The service identifier in jars which provide Project Helper implementations.

See Also:
Constant Field Values
Constructor Detail

ProjectHelper


public ProjectHelper()
Default constructor

Method Detail

configureProject


public static void configureProject(Project project,
                                    java.io.File buildFile)
                             throws BuildException
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

parse


public void parse(Project project,
                  java.lang.Object source)
           throws BuildException
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

getProjectHelper


public static ProjectHelper getProjectHelper()
                                      throws BuildException
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.

getContextClassLoader


public static java.lang.ClassLoader 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.

configure

public static void configure(java.lang.Object target,
                             Project project)
                      throws BuildException
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

addText


public static void addText(Project project,
                           java.lang.Object target,
                           char[] buf,
                           int start,
                           int count)
                    throws BuildException
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,
                           java.lang.Object target,
                           java.lang.String text)
                    throws BuildException
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

storeChild


public static void storeChild(Project project,
                              java.lang.Object parent,
                              java.lang.Object child,
                              java.lang.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.

replaceProperties


public static java.lang.String replaceProperties(Project project,
                                                 java.lang.String value)
                                          throws BuildException
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 java.lang.String replaceProperties(Project project,
                                                 java.lang.String value,
                                                 java.util.Hashtable keys)
                                          throws BuildException
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 }

parsePropertyString


public static void parsePropertyString(java.lang.String value,
                                       java.util.Vector fragments,
                                       java.util.Vector propertyRefs)
                                throws BuildException
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 }


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