Ant example source code file (Locator.java)
The Locator.java source code
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tools.ant.launch;
import java.net.MalformedURLException;
import java.net.URL;
import java.io.File;
import java.io.FilenameFilter;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.text.CharacterIterator;
import java.text.StringCharacterIterator;
import java.util.Locale;
/**
* The Locator is a utility class which is used to find certain items
* in the environment.
*
* @since Ant 1.6
*/
public final class Locator {
/**
* encoding used to represent URIs
*/
public static final String URI_ENCODING = "UTF-8";
// stolen from org.apache.xerces.impl.XMLEntityManager#getUserDir()
// of the Xerces-J team
// which ASCII characters need to be escaped
private static boolean[] gNeedEscaping = new boolean[128];
// the first hex character if a character needs to be escaped
private static char[] gAfterEscaping1 = new char[128];
// the second hex character if a character needs to be escaped
private static char[] gAfterEscaping2 = new char[128];
private static char[] gHexChs = {'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
// initialize the above 3 arrays
static {
for (int i = 0; i <= 0x1f; i++) {
gNeedEscaping[i] = true;
gAfterEscaping1[i] = gHexChs[i >> 4];
gAfterEscaping2[i] = gHexChs[i & 0xf];
}
gNeedEscaping[0x7f] = true;
gAfterEscaping1[0x7f] = '7';
gAfterEscaping2[0x7f] = 'F';
char[] escChs = {' ', '<', '>', '#', '%', '"', '{', '}',
'|', '\\', '^', '~', '[', ']', '`'};
int len = escChs.length;
char ch;
for (int i = 0; i < len; i++) {
ch = escChs[i];
gNeedEscaping[ch] = true;
gAfterEscaping1[ch] = gHexChs[ch >> 4];
gAfterEscaping2[ch] = gHexChs[ch & 0xf];
}
}
/**
* Not instantiable
*/
private Locator() {
}
/**
* Find the directory or jar file the class has been loaded from.
*
* @param c the class whose location is required.
* @return the file or jar with the class or null if we cannot
* determine the location.
*
* @since Ant 1.6
*/
public static File getClassSource(Class c) {
String classResource = c.getName().replace('.', '/') + ".class";
return getResourceSource(c.getClassLoader(), classResource);
}
/**
* Find the directory or jar a given resource has been loaded from.
*
* @param c the classloader to be consulted for the source.
* @param resource the resource whose location is required.
*
* @return the file with the resource source or null if
* we cannot determine the location.
*
* @since Ant 1.6
*/
public static File getResourceSource(ClassLoader c, String resource) {
if (c == null) {
c = Locator.class.getClassLoader();
}
URL url = null;
if (c == null) {
url = ClassLoader.getSystemResource(resource);
} else {
url = c.getResource(resource);
}
if (url != null) {
String u = url.toString();
if (u.startsWith("jar:file:")) {
int pling = u.indexOf("!");
String jarName = u.substring(4, pling);
return new File(fromURI(jarName));
} else if (u.startsWith("file:")) {
int tail = u.indexOf(resource);
String dirName = u.substring(0, tail);
return new File(fromURI(dirName));
}
}
return null;
}
/**
* Constructs a file path from a <code>file: URI.
*
* <p>Will be an absolute path if the given URI is absolute.
*
* <p>Prior to Java 1.4,
* swallows '%' that are not followed by two characters.</p>
*
* See <a href="http://www.w3.org/TR/xml11/#dt-sysid">dt-sysid
* which makes some mention of how
* characters not supported by URI Reference syntax should be escaped.
*
* @param uri the URI designating a file in the local filesystem.
* @return the local file system path for the file.
* @throws IllegalArgumentException if the URI is malformed or not a legal file: URL
* @since Ant 1.6
*/
public static String fromURI(String uri) {
// #8031: first try Java 1.4.
Class uriClazz = null;
try {
uriClazz = Class.forName("java.net.URI");
} catch (ClassNotFoundException cnfe) {
// Fine, Java 1.3 or earlier, do it by hand.
}
// Also check for properly formed URIs. Ant formerly recommended using
// nonsense URIs such as "file:./foo.xml" in XML includes. You shouldn't
// do that (just "foo.xml" is correct) but for compatibility we special-case
// things when the path is not absolute, and fall back to the old parsing behavior.
if (uriClazz != null && uri.startsWith("file:/")) {
try {
java.lang.reflect.Method createMethod
= uriClazz.getMethod("create", new Class[] {String.class});
Object uriObj = createMethod.invoke(null, new Object[] {uri});
java.lang.reflect.Constructor fileConst
= File.class.getConstructor(new Class[] {uriClazz});
File f = (File) fileConst.newInstance(new Object[] {uriObj});
return f.getAbsolutePath();
} catch (java.lang.reflect.InvocationTargetException e) {
Throwable e2 = e.getTargetException();
if (e2 instanceof IllegalArgumentException) {
// Bad URI, pass this on.
throw (IllegalArgumentException) e2;
} else {
// Unexpected target exception? Should not happen.
e2.printStackTrace();
}
} catch (Exception e) {
// Reflection problems? Should not happen, debug.
e.printStackTrace();
}
}
// Fallback method for Java 1.3 or earlier.
URL url = null;
try {
url = new URL(uri);
} catch (MalformedURLException emYouEarlEx) {
// Ignore malformed exception
}
if (url == null || !("file".equals(url.getProtocol()))) {
throw new IllegalArgumentException("Can only handle valid file: URIs");
}
StringBuffer buf = new StringBuffer(url.getHost());
if (buf.length() > 0) {
buf.insert(0, File.separatorChar).insert(0, File.separatorChar);
}
String file = url.getFile();
int queryPos = file.indexOf('?');
buf.append((queryPos < 0) ? file : file.substring(0, queryPos));
uri = buf.toString().replace('/', File.separatorChar);
if (File.pathSeparatorChar == ';' && uri.startsWith("\\") && uri.length() > 2
&& Character.isLetter(uri.charAt(1)) && uri.lastIndexOf(':') > -1) {
uri = uri.substring(1);
}
String path = null;
try {
path = decodeUri(uri);
String cwd = System.getProperty("user.dir");
int posi = cwd.indexOf(":");
if ((posi > 0) && path.startsWith(File.separator)) {
path = cwd.substring(0, posi + 1) + path;
}
} catch (UnsupportedEncodingException exc) {
// not sure whether this is clean, but this method is
// declared not to throw exceptions.
throw new IllegalStateException("Could not convert URI to path: "
+ exc.getMessage());
}
return path;
}
/**
* Decodes an Uri with % characters.
* The URI is escaped
* @param uri String with the uri possibly containing % characters.
* @return The decoded Uri
* @throws UnsupportedEncodingException if UTF-8 is not available
* @since Ant 1.7
*/
public static String decodeUri(String uri) throws UnsupportedEncodingException {
if (uri.indexOf('%') == -1) {
return uri;
}
ByteArrayOutputStream sb = new ByteArrayOutputStream(uri.length());
CharacterIterator iter = new StringCharacterIterator(uri);
for (char c = iter.first(); c != CharacterIterator.DONE;
c = iter.next()) {
if (c == '%') {
char c1 = iter.next();
if (c1 != CharacterIterator.DONE) {
int i1 = Character.digit(c1, 16);
char c2 = iter.next();
if (c2 != CharacterIterator.DONE) {
int i2 = Character.digit(c2, 16);
sb.write((char) ((i1 << 4) + i2));
}
}
} else {
sb.write(c);
}
}
return sb.toString(URI_ENCODING);
}
/**
* Encodes an Uri with % characters.
* The URI is escaped
* @param path String to encode.
* @return The encoded string, according to URI norms
* @throws UnsupportedEncodingException if UTF-8 is not available
* @since Ant 1.7
*/
public static String encodeURI(String path) throws UnsupportedEncodingException {
int i = 0;
int len = path.length();
int ch = 0;
StringBuffer sb = null;
for (; i < len; i++) {
ch = path.charAt(i);
// if it's not an ASCII character, break here, and use UTF-8 encoding
if (ch >= 128) {
break;
}
if (gNeedEscaping[ch]) {
if (sb == null) {
sb = new StringBuffer(path.substring(0, i));
}
sb.append('%');
sb.append(gAfterEscaping1[ch]);
sb.append(gAfterEscaping2[ch]);
// record the fact that it's escaped
} else if (sb != null) {
sb.append((char) ch);
}
}
// we saw some non-ascii character
if (i < len) {
if (sb == null) {
sb = new StringBuffer(path.substring(0, i));
}
// get UTF-8 bytes for the remaining sub-string
byte[] bytes = null;
byte b;
bytes = path.substring(i).getBytes(URI_ENCODING);
len = bytes.length;
// for each byte
for (i = 0; i < len; i++) {
b = bytes[i];
// for non-ascii character: make it positive, then escape
if (b < 0) {
ch = b + 256;
sb.append('%');
sb.append(gHexChs[ch >> 4]);
sb.append(gHexChs[ch & 0xf]);
} else if (gNeedEscaping[b]) {
sb.append('%');
sb.append(gAfterEscaping1[b]);
sb.append(gAfterEscaping2[b]);
} else {
sb.append((char) b);
}
}
}
return sb == null ? path : sb.toString();
}
/**
* Convert a File to a URL.
* File.toURL() does not encode characters like #.
* File.toURI() has been introduced in java 1.4, so
* ANT cannot use it (except by reflection)
* FileUtils.toURI() cannot be used by Locator.java
* Implemented this way.
* File.toURL() adds file: and changes '\' to '/' for dos OSes
* encodeURI converts characters like ' ' and '#' to %DD
* @param file the file to convert
* @return URL the converted File
* @throws MalformedURLException on error
*/
public static URL fileToURL(File file)
throws MalformedURLException {
try {
return new URL(encodeURI(file.toURL().toString()));
} catch (UnsupportedEncodingException ex) {
throw new MalformedURLException(ex.toString());
}
}
/**
* Get the File necessary to load the Sun compiler tools. If the classes
* are available to this class, then no additional URL is required and
* null is returned. This may be because the classes are explicitly in the
* class path or provided by the JVM directly.
*
* @return the tools jar as a File if required, null otherwise.
*/
public static File getToolsJar() {
// firstly check if the tools jar is already in the classpath
boolean toolsJarAvailable = false;
try {
// just check whether this throws an exception
Class.forName("com.sun.tools.javac.Main");
toolsJarAvailable = true;
} catch (Exception e) {
try {
Class.forName("sun.tools.javac.Main");
toolsJarAvailable = true;
} catch (Exception e2) {
// ignore
}
}
if (toolsJarAvailable) {
return null;
}
// couldn't find compiler - try to find tools.jar
// based on java.home setting
String javaHome = System.getProperty("java.home");
File toolsJar = new File(javaHome + "/lib/tools.jar");
if (toolsJar.exists()) {
// Found in java.home as given
return toolsJar;
}
if (javaHome.toLowerCase(Locale.US).endsWith(File.separator + "jre")) {
javaHome = javaHome.substring(0, javaHome.length() - 4);
toolsJar = new File(javaHome + "/lib/tools.jar");
}
if (!toolsJar.exists()) {
System.out.println("Unable to locate tools.jar. "
+ "Expected to find it in " + toolsJar.getPath());
return null;
}
return toolsJar;
}
/**
* Get an array of URLs representing all of the jar files in the
* given location. If the location is a file, it is returned as the only
* element of the array. If the location is a directory, it is scanned for
* jar files.
*
* @param location the location to scan for Jars.
*
* @return an array of URLs for all jars in the given location.
*
* @exception MalformedURLException if the URLs for the jars cannot be
* formed.
*/
public static URL[] getLocationURLs(File location)
throws MalformedURLException {
return getLocationURLs(location, new String[]{".jar"});
}
/**
* Get an array of URLs representing all of the files of a given set of
* extensions in the given location. If the location is a file, it is
* returned as the only element of the array. If the location is a
* directory, it is scanned for matching files.
*
* @param location the location to scan for files.
* @param extensions an array of extension that are to match in the
* directory search.
*
* @return an array of URLs of matching files.
* @exception MalformedURLException if the URLs for the files cannot be
* formed.
*/
public static URL[] getLocationURLs(File location,
final String[] extensions)
throws MalformedURLException {
URL[] urls = new URL[0];
if (!location.exists()) {
return urls;
}
if (!location.isDirectory()) {
urls = new URL[1];
String path = location.getPath();
for (int i = 0; i < extensions.length; ++i) {
if (path.toLowerCase().endsWith(extensions[i])) {
urls[0] = fileToURL(location);
break;
}
}
return urls;
}
File[] matches = location.listFiles(
new FilenameFilter() {
public boolean accept(File dir, String name) {
for (int i = 0; i < extensions.length; ++i) {
if (name.toLowerCase().endsWith(extensions[i])) {
return true;
}
}
return false;
}
});
urls = new URL[matches.length];
for (int i = 0; i < matches.length; ++i) {
urls[i] = fileToURL(matches[i]);
}
return urls;
}
}
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