* <antlib library="libname.jar" > * <alias name="nameOnLib" as="newName" /> * </antlib> * * <antlib file="libname.jar" override="true" /> ** @author Jose Alberto Fernandez */ public class Antlib extends Task implements DeclaringTask { /** Location of destriptor in library */ public static String XML_DESCRIPTOR = "META-INF/antlib.xml"; /** Prefix name for DTD of descriptor */ public static String ANTLIB_DTD_PREFIX = "Antlib-V"; public static String ANTLIB_DTD_EXT = ".dtd"; private String library = null; private File file = null; private boolean override = false; private boolean onCurrent = false; private SAXParserFactory saxFactory; private Vector aliases = new Vector(); public class Alias { private String name; private String as; public void setName(String name) { this.name = name; } public void setAs(String as) { this.as = as; } } public Antlib() { super(); saxFactory = SAXParserFactory.newInstance(); saxFactory.setValidating(true); } public Antlib(Project p) { this(); setProject(p); } /** * Set name of library to load. The library is located in $ANT_HOME/lib. * @param lib the name of library relative to $ANT_HOME/lib. */ public void setLibrary(String lib) { this.library = lib; } /** * Set file location of library to load. * @param file the jar file for the library. */ public void setFile(File file) { this.file = file; } /** * Set whether to override any existing definitions. * @param override if true new definitions will replace existing ones. */ public void setOverride(boolean override) { this.override = override; } /** * Set whether to use a new classloader or not. * Default is
false.
* This property is mostly used by the core when loading core tasks.
* @param onCurrent if true the current classloader will be used to
* load the definitions.
*/
public void setOnCurrent(boolean onCurrent) {
this.onCurrent = onCurrent;
}
/** Create new Alias element. */
public Alias createAlias() {
Alias als = new Alias();
aliases.add(als);
return als;
}
public void execute() throws BuildException {
File realFile = file;
if (library != null) {
if (file != null) {
String msg = "You cannot specify both file and library.";
throw new BuildException(msg, location);
}
// For the time being libraries live in $ANT_HOME/lib.
// The idea being that we would not load all the jar there anymore
String home = project.getProperty("ant.home");
if (home == null)
throw new BuildException("ANT_HOME not set as required.");
realFile = new File(new File(home, "lib"), library);
}
else if (file == null) {
String msg = "Must specify either library or file attribute.";
throw new BuildException(msg, location);
}
if (!realFile.exists()) {
String msg = "Cannot find library: " + realFile;
throw new BuildException(msg, location);
}
InputStream is = getDescriptor(realFile);
if (is == null) {
String msg = "Missing descriptor on library: " + realFile;
throw new BuildException(msg, location);
}
evaluateDescriptor(onCurrent? null : makeClassLoader(realFile),
processAliases(), is);
}
/**
* Load definitions directly from an external XML file.
* @param xmlfile XML file in the Antlib format.
*/
public void loadDefinitions(File xmlfile) throws BuildException {
try {
InputStream is = new FileInputStream(xmlfile);
loadDefinitions(is);
}
catch (IOException io) {
throw new BuildException("Cannot read file: " + file, io);
}
}
/**
* Load definitions directly from InputStream.
* @param is InputStream for the Antlib descriptor.
*/
public void loadDefinitions(InputStream is) throws BuildException {
evaluateDescriptor(null, processAliases(), is);
}
private InputStream getDescriptor(File file) {
try {
final ZipFile zipfile = new ZipFile(file);
ZipEntry entry = zipfile.getEntry(XML_DESCRIPTOR);
if (entry == null) return null;
// Guarantee that when Entry is close so does the zipfile instance.
return new FilterInputStream(zipfile.getInputStream(entry)){
public void close() throws IOException {
super.close();
zipfile.close();
}
};
}
catch(ZipException ze) {
throw new BuildException("Not a library file.", ze, location);
}
catch(IOException ioe) {
throw new BuildException("Cannot read library content.",
ioe, location);
}
}
private Properties processAliases() {
Properties p = new Properties();
for(Enumeration e = aliases.elements(); e.hasMoreElements();) {
Alias a = (Alias)e.nextElement();
p.put(a.name, a.as);
}
return p;
}
protected ClassLoader makeClassLoader(File fl) throws BuildException {
Path clspath = new Path(project);
clspath.setLocation(fl);
AntClassLoader al = new AntClassLoader(project, clspath, true);
return al;
}
protected void evaluateDescriptor(ClassLoader cl,
Properties als, InputStream is)
throws BuildException
{
try {
SAXParser saxParser = saxFactory.newSAXParser();
Parser parser = saxParser.getParser();
InputSource inputSource = new InputSource(is);
//inputSource.setSystemId(uri); //URI is nasty for jar entries
project.log("parsing descriptor for library: " + file,
Project.MSG_VERBOSE);
saxParser.parse(inputSource, new AntLibraryHandler(cl, als));
}
catch(ParserConfigurationException exc) {
throw new BuildException("Parser has not been configured correctly", exc);
}
catch(SAXParseException exc) {
Location location =
new Location(XML_DESCRIPTOR,
exc.getLineNumber(), exc.getColumnNumber());
Throwable t = exc.getException();
if (t instanceof BuildException) {
BuildException be = (BuildException) t;
if (be.getLocation() == Location.UNKNOWN_LOCATION) {
be.setLocation(location);
}
throw be;
}
throw new BuildException(exc.getMessage(), t, location);
}
catch(SAXException exc) {
Throwable t = exc.getException();
if (t instanceof BuildException) {
throw (BuildException) t;
}
throw new BuildException(exc.getMessage(), t);
}
catch(IOException exc) {
throw new BuildException("Error reading library descriptor", exc);
}
finally {
if (is != null) {
try {
is.close();
}
catch (IOException ioe) {
// ignore this
}
}
}
}
/**
* Parses the document describing the content of the library.
*/
private class AntLibraryHandler extends HandlerBase {
private final ClassLoader cl;
private final Properties aliasMap;
private Locator locator = null;
AntLibraryHandler(ClassLoader cl, Properties als) {
this.cl = cl;
this.aliasMap = als;
}
public void setDocumentLocator(Locator locator) {
this.locator = locator;
}
public void startElement(String tag, AttributeList attrs)
throws SAXParseException
{
if ("antlib".equals(tag)) {
// No attributes to worry about
return;
}
if ("task".equals(tag) || "type".equals(tag)) {
String name = null;
String className = null;
for (int i = 0, last = attrs.getLength(); i < last; i++) {
String key = attrs.getName(i);
String value = attrs.getValue(i);
if (key.equals("name")) {
name = value;
} else if (key.equals("class")) {
className = value;
} else {
throw new SAXParseException("Unexpected attribute \""
+ key + "\"", locator);
}
}
if (name == null || className == null) {
String msg = "Underspecified " + tag + " declaration.";
throw new SAXParseException(msg, locator);
}
try {
String alias = aliasMap.getProperty(name);
if (alias != null) name = alias;
if (!override && inUse(name)) {
String msg = "Cannot override " + tag + ": " + name;
log(msg, Project.MSG_WARN);
return;
}
Class cls = (cl != null)?
cl.loadClass(className) : Class.forName(className);
if (tag.equals("task")) {
project.addTaskDefinition(name, cls);
} else {
project.addDataTypeDefinition(name, cls);
}
} catch (ClassNotFoundException cnfe) {
String msg = "Class " + className +
" cannot be found";
throw new SAXParseException(msg, locator, cnfe);
} catch (NoClassDefFoundError ncdfe) {
String msg = "Class " + className +
" cannot be found";
throw new SAXParseException(msg, locator);
}
}
else {
throw new SAXParseException("Unexpected element \"" +
tag + "\"",
locator);
}
}
private boolean inUse(String name) {
return (project.getTaskDefinitions().get(name) != null ||
project.getDataTypeDefinitions().get(name) != null);
}
/**
* Recognizes the DTD declaration for antlib and returns
* the corresponding DTD definition from a resource.
* * To allow for future versions of the DTD format it will * search for any DTDs of the form "Antlib-V.*\.dtd". */ public InputSource resolveEntity(String publicId, String systemId) { if (systemId != null && systemId.startsWith(ANTLIB_DTD_PREFIX) && systemId.endsWith(ANTLIB_DTD_EXT)) { InputSource is = new InputSource(getClass().getResourceAsStream(systemId)); is.setSystemId(systemId); return is; } return null; } } }