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| //这里能看出，META-INF/services/是两个文件夹，我在使用过程中，建成了一个，导致一直失败
private static final String PREFIX = "META-INF/services/";
private class LazyIterator implements Iterator<S>
{
private boolean hasNextService() {
if (nextName != null) {
return true;
}
// configs = URL = jar:file:/data/app/com.myapplication-1/base.apk!/META-INF/services/com.myapplication.spi.ISPIService
if (configs == null) {
try {
//service的文件全路径名
String fullName = PREFIX + service.getName();
//loader == null就是系统SystemClassLoader.loader，否则自己的loader
if (loader == null)
configs = ClassLoader.getSystemResources(fullName);
else
configs = loader.getResources(fullName);
} catch (IOException x) {
}
}
// pending 就是fullName文件中的实现类
while ((pending == null) || !pending.hasNext()) {
if (!configs.hasMoreElements()) {
return false;
}
//解析service文件
pending = parse(service, configs.nextElement());
}
nextName = pending.next();
return true;
}
//通过反射拿到实现类的对象
private S nextService() {
if (!hasNextService())
throw new NoSuchElementException();
String cn = nextName;
nextName = null;
Class<?> c = null;
try {
c = Class.forName(cn, false, loader);
} catch (ClassNotFoundException x) {
}
try {
S p = service.cast(c.newInstance());
providers.put(cn, p);
return p;
} catch (Throwable x) {
x);
}
}
public boolean hasNext() {
// Android-changed: do not use legacy security code
/* if (acc == null) { */
return hasNextService();
/*
} else {
PrivilegedAction<Boolean> action = new PrivilegedAction<Boolean>() {
public Boolean run() { return hasNextService(); }
};
return AccessController.doPrivileged(action, acc);
}
*/
}
// 取实现对象
public S next() {
// Android-changed: do not use legacy security code
/* if (acc == null) { */
return nextService();
/*
} else {
PrivilegedAction<S> action = new PrivilegedAction<S>() {
public S run() { return nextService(); }
};
return AccessController.doPrivileged(action, acc);
}
*/
}
public void remove() {
throw new UnsupportedOperationException();
}
}
private LinkedHashMap<String,S> providers = new LinkedHashMap<>();
//读文件啊，解析文件内容，按行截取，放到list里，首行排到第一位0，顺序依次
private Iterator<String> parse(Class<?> service, URL u) throws ServiceConfigurationError
{
InputStream in = null;
BufferedReader r = null;
ArrayList<String> names = new ArrayList<>();
try {
in = u.openStream();
r = new BufferedReader(new InputStreamReader(in, "utf-8"));
int lc = 1;
while ((lc = parseLine(service, u, r, lc, names)) >= 0);
} catch (IOException x) {
fail(service, "Error reading configuration file", x);
} finally {
try {
if (r != null) r.close();
if (in != null) in.close();
} catch (IOException y) {
fail(service, "Error closing configuration file", y);
}
}
return names.iterator();
}
private int parseLine(Class<?> service, URL u, BufferedReader r, int lc, List<String> names) throws IOException, ServiceConfigurationError
{
String ln = r.readLine();
if (ln == null) {
return -1;
}
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);
}
if (!providers.containsKey(ln) && !names.contains(ln))
names.add(ln);
}
return lc + 1;
}
|
