/*
* Copyright (c) 2006, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
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*/
package com.sun.tools.javac.processing;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
Utility class to determine if a service can be found on the
path that might be used to create a class loader.
This is NOT part of any supported API.
If you write code that depends on this, you do so at your own risk.
This code and its internal interfaces are subject to change or
deletion without notice.
/**
* Utility class to determine if a service can be found on the
* path that might be used to create a class loader.
*
* <p><b>This is NOT part of any supported API.
* If you write code that depends on this, you do so at your own risk.
* This code and its internal interfaces are subject to change or
* deletion without notice.</b>
*
*/
// based on sun.misc.Service
class ServiceProxy {
static class ServiceConfigurationError extends Error {
static final long serialVersionUID = 7732091036771098303L;
ServiceConfigurationError(String msg) {
super(msg);
}
}
private static final String prefix = "META-INF/services/";
private static void fail(Class<?> service, String msg)
throws ServiceConfigurationError {
throw new ServiceConfigurationError(service.getName() + ": " + msg);
}
private static void fail(Class<?> service, URL u, int line, String msg)
throws ServiceConfigurationError {
fail(service, u + ":" + line + ": " + msg);
}
Parse the content of the given URL as a provider-configuration file.
Params: - service –
The service class for which providers are being sought;
used to construct error detail strings
- u –
The URL naming the configuration file to be parsed
Throws: - ServiceConfigurationError –
If an I/O error occurs while reading from the given URL, or
if a configuration-file format error is detected
Returns: true if the name of a service is found
/**
* Parse the content of the given URL as a provider-configuration file.
*
* @param service
* The service class for which providers are being sought;
* used to construct error detail strings
*
* @param u
* The URL naming the configuration file to be parsed
*
* @return true if the name of a service is found
*
* @throws ServiceConfigurationError
* If an I/O error occurs while reading from the given URL, or
* if a configuration-file format error is detected
*/
private static boolean parse(Class<?> service, URL u) throws ServiceConfigurationError {
InputStream in = null;
BufferedReader r = null;
try {
in = u.openStream();
r = new BufferedReader(new InputStreamReader(in, "utf-8"));
int lc = 1;
String ln;
while ((ln = r.readLine()) != null) {
int ci = ln.indexOf('#');
if (ci >= 0) ln = ln.substring(0, ci);
ln = ln.trim();
int n = ln.length();
if (n != 0) {
if ((ln.indexOf(' ') >= 0) || (ln.indexOf('\t') >= 0))
fail(service, u, lc, "Illegal configuration-file syntax");
int cp = ln.codePointAt(0);
if (!Character.isJavaIdentifierStart(cp))
fail(service, u, lc, "Illegal provider-class name: " + ln);
for (int i = Character.charCount(cp); i < n; i += Character.charCount(cp)) {
cp = ln.codePointAt(i);
if (!Character.isJavaIdentifierPart(cp) && (cp != '.'))
fail(service, u, lc, "Illegal provider-class name: " + ln);
}
return true;
}
}
} catch (FileNotFoundException x) {
return false;
} catch (IOException x) {
fail(service, ": " + x);
} finally {
try {
if (r != null) r.close();
} catch (IOException y) {
fail(service, ": " + y);
}
try {
if (in != null) in.close();
} catch (IOException y) {
fail(service, ": " + y);
}
}
return false;
}
Return true if a description for at least one service is found in the
service configuration files in the given URLs.
/**
* Return true if a description for at least one service is found in the
* service configuration files in the given URLs.
*/
public static boolean hasService(Class<?> service, URL[] urls)
throws ServiceConfigurationError {
for (URL url: urls) {
try {
String fullName = prefix + service.getName();
URL u = new URL(url, fullName);
boolean found = parse(service, u);
if (found)
return true;
} catch (MalformedURLException e) {
// should not happen; ignore it if it does
}
}
return false;
}
}