JDK8/Java8源码在线阅读
/*
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* 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
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package javax.naming.spi;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.StringTokenizer;
import java.net.MalformedURLException;
import javax.naming.*;
import com.sun.naming.internal.VersionHelper;
import com.sun.naming.internal.ResourceManager;
import com.sun.naming.internal.FactoryEnumeration;
/**
* This class contains methods for creating context objects
* and objects referred to by location information in the naming
* or directory service.
*<p>
* This class cannot be instantiated. It has only static methods.
*<p>
* The mention of URL in the documentation for this class refers to
* a URL string as defined by RFC 1738 and its related RFCs. It is
* any string that conforms to the syntax described therein, and
* may not always have corresponding support in the java.net.URL
* class or Web browsers.
*<p>
* NamingManager is safe for concurrent access by multiple threads.
*<p>
* Except as otherwise noted,
* a <tt>Name</tt> or environment parameter
* passed to any method is owned by the caller.
* The implementation will not modify the object or keep a reference
* to it, although it may keep a reference to a clone or copy.
*
* @author Rosanna Lee
* @author Scott Seligman
* @since 1.3
*/
public class NamingManager {
/*
* Disallow anyone from creating one of these.
* Made package private so that DirectoryManager can subclass.
*/
NamingManager() {}
// should be protected and package private
static final VersionHelper helper = VersionHelper.getVersionHelper();
// --------- object factory stuff
/**
* Package-private; used by DirectoryManager and NamingManager.
*/
private static ObjectFactoryBuilder object_factory_builder = null;
/**
* The ObjectFactoryBuilder determines the policy used when
* trying to load object factories.
* See getObjectInstance() and class ObjectFactory for a description
* of the default policy.
* setObjectFactoryBuilder() overrides this default policy by installing
* an ObjectFactoryBuilder. Subsequent object factories will
* be loaded and created using the installed builder.
*<p>
* The builder can only be installed if the executing thread is allowed
* (by the security manager's checkSetFactory() method) to do so.
* Once installed, the builder cannot be replaced.
*<p>
* @param builder The factory builder to install. If null, no builder
* is installed.
* @exception SecurityException builder cannot be installed
* for security reasons.
* @exception NamingException builder cannot be installed for
* a non-security-related reason.
* @exception IllegalStateException If a factory has already been installed.
* @see #getObjectInstance
* @see ObjectFactory
* @see ObjectFactoryBuilder
* @see java.lang.SecurityManager#checkSetFactory
*/
public static synchronized void setObjectFactoryBuilder(
ObjectFactoryBuilder builder) throws NamingException {
if (object_factory_builder != null)
throw new IllegalStateException("ObjectFactoryBuilder already set");
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkSetFactory();
}
object_factory_builder = builder;
}
/**
* Used for accessing object factory builder.
*/
static synchronized ObjectFactoryBuilder getObjectFactoryBuilder() {
return object_factory_builder;
}
/**
* Retrieves the ObjectFactory for the object identified by a reference,
* using the reference's factory class name and factory codebase
* to load in the factory's class.
* @param ref The non-null reference to use.
* @param factoryName The non-null class name of the factory.
* @return The object factory for the object identified by ref; null
* if unable to load the factory.
*/
static ObjectFactory getObjectFactoryFromReference(
Reference ref, String factoryName)
throws IllegalAccessException,
InstantiationException,
MalformedURLException {
Class<?> clas = null;
// Try to use current class loader
try {
clas = helper.loadClass(factoryName);
} catch (ClassNotFoundException e) {
// ignore and continue
// e.printStackTrace();
}
// All other exceptions are passed up.
// Not in class path; try to use codebase
String codebase;
if (clas == null &&
(codebase = ref.getFactoryClassLocation()) != null) {
try {
clas = helper.loadClass(factoryName, codebase);
} catch (ClassNotFoundException e) {
}
}
return (clas != null) ? (ObjectFactory) clas.newInstance() : null;
}
/**
* Creates an object using the factories specified in the
* <tt>Context.OBJECT_FACTORIES</tt> property of the environment
* or of the provider resource file associated with <tt>nameCtx</tt>.
*
* @return factory created; null if cannot create
*/
private static Object createObjectFromFactories(Object obj, Name name,
Context nameCtx, Hashtable<?,?> environment) throws Exception {
FactoryEnumeration factories = ResourceManager.getFactories(
Context.OBJECT_FACTORIES, environment, nameCtx);
if (factories == null)
return null;
// Try each factory until one succeeds
ObjectFactory factory;
Object answer = null;
while (answer == null && factories.hasMore()) {
factory = (ObjectFactory)factories.next();
answer = factory.getObjectInstance(obj, name, nameCtx, environment);
}
return answer;
}
private static String getURLScheme(String str) {
int colon_posn = str.indexOf(':');
int slash_posn = str.indexOf('/');
if (colon_posn > 0 && (slash_posn == -1 || colon_posn < slash_posn))
return str.substring(0, colon_posn);
return null;
}
/**
* Creates an instance of an object for the specified object
* and environment.
* <p>
* If an object factory builder has been installed, it is used to
* create a factory for creating the object.
* Otherwise, the following rules are used to create the object:
*<ol>
* <li>If <code>refInfo</code> is a <code>Reference</code>
* or <code>Referenceable</code> containing a factory class name,
* use the named factory to create the object.
* Return <code>refInfo</code> if the factory cannot be created.
* Under JDK 1.1, if the factory class must be loaded from a location
* specified in the reference, a <tt>SecurityManager</tt> must have
* been installed or the factory creation will fail.
* If an exception is encountered while creating the factory,
* it is passed up to the caller.
* <li>If <tt>refInfo</tt> is a <tt>Reference</tt> or
* <tt>Referenceable</tt> with no factory class name,
* and the address or addresses are <tt>StringRefAddr</tt>s with
* address type "URL",
* try the URL context factory corresponding to each URL's scheme id
* to create the object (see <tt>getURLContext()</tt>).
* If that fails, continue to the next step.
* <li> Use the object factories specified in
* the <tt>Context.OBJECT_FACTORIES</tt> property of the environment,
* and of the provider resource file associated with
* <tt>nameCtx</tt>, in that order.
* The value of this property is a colon-separated list of factory
* class names that are tried in order, and the first one that succeeds
* in creating an object is the one used.
* If none of the factories can be loaded,
* return <code>refInfo</code>.
* If an exception is encountered while creating the object, the
* exception is passed up to the caller.
*</ol>
*<p>
* Service providers that implement the <tt>DirContext</tt>
* interface should use
* <tt>DirectoryManager.getObjectInstance()</tt>, not this method.
* Service providers that implement only the <tt>Context</tt>
* interface should use this method.
* <p>
* Note that an object factory (an object that implements the ObjectFactory
* interface) must be public and must have a public constructor that
* accepts no arguments.
* <p>
* The <code>name</code> and <code>nameCtx</code> parameters may
* optionally be used to specify the name of the object being created.
* <code>name</code> is the name of the object, relative to context
* <code>nameCtx</code>. This information could be useful to the object
* factory or to the object implementation.
* If there are several possible contexts from which the object
* could be named -- as will often be the case -- it is up to
* the caller to select one. A good rule of thumb is to select the
* "deepest" context available.
* If <code>nameCtx</code> is null, <code>name</code> is relative
* to the default initial context. If no name is being specified, the
* <code>name</code> parameter should be null.
*
* @param refInfo The possibly null object for which to create an object.
* @param name The name of this object relative to <code>nameCtx</code>.
* Specifying a name is optional; if it is
* omitted, <code>name</code> should be null.
* @param nameCtx The context relative to which the <code>name</code>
* parameter is specified. If null, <code>name</code> is
* relative to the default initial context.
* @param environment The possibly null environment to
* be used in the creation of the object factory and the object.
* @return An object created using <code>refInfo</code>; or
* <code>refInfo</code> if an object cannot be created using
* the algorithm described above.
* @exception NamingException if a naming exception was encountered
* while attempting to get a URL context, or if one of the
* factories accessed throws a NamingException.
* @exception Exception if one of the factories accessed throws an
* exception, or if an error was encountered while loading
* and instantiating the factory and object classes.
* A factory should only throw an exception if it does not want
* other factories to be used in an attempt to create an object.
* See ObjectFactory.getObjectInstance().
* @see #getURLContext
* @see ObjectFactory
* @see ObjectFactory#getObjectInstance
*/
public static Object
getObjectInstance(Object refInfo, Name name, Context nameCtx,
Hashtable<?,?> environment)
throws Exception
{
ObjectFactory factory;
// Use builder if installed
ObjectFactoryBuilder builder = getObjectFactoryBuilder();
if (builder != null) {
// builder must return non-null factory
factory = builder.createObjectFactory(refInfo, environment);
return factory.getObjectInstance(refInfo, name, nameCtx,
environment);
}
// Use reference if possible
Reference ref = null;
if (refInfo instanceof Reference) {
ref = (Reference) refInfo;
} else if (refInfo instanceof Referenceable) {
ref = ((Referenceable)(refInfo)).getReference();
}
Object answer;
if (ref != null) {
String f = ref.getFactoryClassName();
if (f != null) {
// if reference identifies a factory, use exclusively
factory = getObjectFactoryFromReference(ref, f);
if (factory != null) {
return factory.getObjectInstance(ref, name, nameCtx,
environment);
}
// No factory found, so return original refInfo.
// Will reach this point if factory class is not in
// class path and reference does not contain a URL for it
return refInfo;
} else {
// if reference has no factory, check for addresses
// containing URLs
answer = processURLAddrs(ref, name, nameCtx, environment);
if (answer != null) {
return answer;
}
}
}
// try using any specified factories
answer =
createObjectFromFactories(refInfo, name, nameCtx, environment);
return (answer != null) ? answer : refInfo;
}
/*
* Ref has no factory. For each address of type "URL", try its URL
* context factory. Returns null if unsuccessful in creating and
* invoking a factory.
*/
static Object processURLAddrs(Reference ref, Name name, Context nameCtx,
Hashtable<?,?> environment)
throws NamingException {
for (int i = 0; i < ref.size(); i++) {
RefAddr addr = ref.get(i);
if (addr instanceof StringRefAddr &&
addr.getType().equalsIgnoreCase("URL")) {
String url = (String)addr.getContent();
Object answer = processURL(url, name, nameCtx, environment);
if (answer != null) {
return answer;
}
}
}
return null;
}
private static Object processURL(Object refInfo, Name name,
Context nameCtx, Hashtable<?,?> environment)
throws NamingException {
Object answer;
// If refInfo is a URL string, try to use its URL context factory
// If no context found, continue to try object factories.
if (refInfo instanceof String) {
String url = (String)refInfo;
String scheme = getURLScheme(url);
if (scheme != null) {
answer = getURLObject(scheme, refInfo, name, nameCtx,
environment);
if (answer != null) {
return answer;
}
}
}
// If refInfo is an array of URL strings,
// try to find a context factory for any one of its URLs.
// If no context found, continue to try object factories.
if (refInfo instanceof String[]) {
String[] urls = (String[])refInfo;
for (int i = 0; i <urls.length; i++) {
String scheme = getURLScheme(urls[i]);
if (scheme != null) {
answer = getURLObject(scheme, refInfo, name, nameCtx,
environment);
if (answer != null)
return answer;
}
}
}
return null;
}
/**
* Retrieves a context identified by <code>obj</code>, using the specified
* environment.
* Used by ContinuationContext.
*
* @param obj The object identifying the context.
* @param name The name of the context being returned, relative to
* <code>nameCtx</code>, or null if no name is being
* specified.
* See the <code>getObjectInstance</code> method for
* details.
* @param nameCtx The context relative to which <code>name</code> is
* specified, or null for the default initial context.
* See the <code>getObjectInstance</code> method for
* details.
* @param environment Environment specifying characteristics of the
* resulting context.
* @return A context identified by <code>obj</code>.
*
* @see #getObjectInstance
*/
static Context getContext(Object obj, Name name, Context nameCtx,
Hashtable<?,?> environment) throws NamingException {
Object answer;
if (obj instanceof Context) {
// %%% Ignore environment for now. OK since method not public.
return (Context)obj;
}
try {
answer = getObjectInstance(obj, name, nameCtx, environment);
} catch (NamingException e) {
throw e;
} catch (Exception e) {
NamingException ne = new NamingException();
ne.setRootCause(e);
throw ne;
}
return (answer instanceof Context)
? (Context)answer
: null;
}
// Used by ContinuationContext
static Resolver getResolver(Object obj, Name name, Context nameCtx,
Hashtable<?,?> environment) throws NamingException {
Object answer;
if (obj instanceof Resolver) {
// %%% Ignore environment for now. OK since method not public.
return (Resolver)obj;
}
try {
answer = getObjectInstance(obj, name, nameCtx, environment);
} catch (NamingException e) {
throw e;
} catch (Exception e) {
NamingException ne = new NamingException();
ne.setRootCause(e);
throw ne;
}
return (answer instanceof Resolver)
? (Resolver)answer
: null;
}
/***************** URL Context implementations ***************/
/**
* Creates a context for the given URL scheme id.
* <p>
* The resulting context is for resolving URLs of the
* scheme <code>scheme</code>. The resulting context is not tied
* to a specific URL. It is able to handle arbitrary URLs with
* the specified scheme.
*<p>
* The class name of the factory that creates the resulting context
* has the naming convention <i>scheme-id</i>URLContextFactory
* (e.g. "ftpURLContextFactory" for the "ftp" scheme-id),
* in the package specified as follows.
* The <tt>Context.URL_PKG_PREFIXES</tt> environment property (which
* may contain values taken from applet parameters, system properties,
* or application resource files)
* contains a colon-separated list of package prefixes.
* Each package prefix in
* the property is tried in the order specified to load the factory class.
* The default package prefix is "com.sun.jndi.url" (if none of the
* specified packages work, this default is tried).
* The complete package name is constructed using the package prefix,
* concatenated with the scheme id.
*<p>
* For example, if the scheme id is "ldap", and the
* <tt>Context.URL_PKG_PREFIXES</tt> property
* contains "com.widget:com.wiz.jndi",
* the naming manager would attempt to load the following classes
* until one is successfully instantiated:
*<ul>
* <li>com.widget.ldap.ldapURLContextFactory
* <li>com.wiz.jndi.ldap.ldapURLContextFactory
* <li>com.sun.jndi.url.ldap.ldapURLContextFactory
*</ul>
* If none of the package prefixes work, null is returned.
*<p>
* If a factory is instantiated, it is invoked with the following
* parameters to produce the resulting context.
* <p>
* <code>factory.getObjectInstance(null, environment);</code>
* <p>
* For example, invoking getObjectInstance() as shown above
* on a LDAP URL context factory would return a
* context that can resolve LDAP urls
* (e.g. "ldap://ldap.wiz.com/o=wiz,c=us",
* "ldap://ldap.umich.edu/o=umich,c=us", ...).
*<p>
* Note that an object factory (an object that implements the ObjectFactory
* interface) must be public and must have a public constructor that
* accepts no arguments.
*
* @param scheme The non-null scheme-id of the URLs supported by the context.
* @param environment The possibly null environment properties to be
* used in the creation of the object factory and the context.
* @return A context for resolving URLs with the
* scheme id <code>scheme</code>;
* <code>null</code> if the factory for creating the
* context is not found.
* @exception NamingException If a naming exception occurs while creating
* the context.
* @see #getObjectInstance
* @see ObjectFactory#getObjectInstance
*/
public static Context getURLContext(String scheme,
Hashtable<?,?> environment)
throws NamingException
{
// pass in 'null' to indicate creation of generic context for scheme
// (i.e. not specific to a URL).
Object answer = getURLObject(scheme, null, null, null, environment);
if (answer instanceof Context) {
return (Context)answer;
} else {
return null;
}
}
private static final String defaultPkgPrefix = "com.sun.jndi.url";
/**
* Creates an object for the given URL scheme id using
* the supplied urlInfo.
* <p>
* If urlInfo is null, the result is a context for resolving URLs
* with the scheme id 'scheme'.
* If urlInfo is a URL, the result is a context named by the URL.
* Names passed to this context is assumed to be relative to this
* context (i.e. not a URL). For example, if urlInfo is
* "ldap://ldap.wiz.com/o=Wiz,c=us", the resulting context will
* be that pointed to by "o=Wiz,c=us" on the server 'ldap.wiz.com'.
* Subsequent names that can be passed to this context will be
* LDAP names relative to this context (e.g. cn="Barbs Jensen").
* If urlInfo is an array of URLs, the URLs are assumed
* to be equivalent in terms of the context to which they refer.
* The resulting context is like that of the single URL case.
* If urlInfo is of any other type, that is handled by the
* context factory for the URL scheme.
* @param scheme the URL scheme id for the context
* @param urlInfo information used to create the context
* @param name name of this object relative to <code>nameCtx</code>
* @param nameCtx Context whose provider resource file will be searched
* for package prefix values (or null if none)
* @param environment Environment properties for creating the context
* @see javax.naming.InitialContext
*/
private static Object getURLObject(String scheme, Object urlInfo,
Name name, Context nameCtx,
Hashtable<?,?> environment)
throws NamingException {
// e.g. "ftpURLContextFactory"
ObjectFactory factory = (ObjectFactory)ResourceManager.getFactory(
Context.URL_PKG_PREFIXES, environment, nameCtx,
"." + scheme + "." + scheme + "URLContextFactory", defaultPkgPrefix);
if (factory == null)
return null;
// Found object factory
try {
return factory.getObjectInstance(urlInfo, name, nameCtx, environment);
} catch (NamingException e) {
throw e;
} catch (Exception e) {
NamingException ne = new NamingException();
ne.setRootCause(e);
throw ne;
}
}
// ------------ Initial Context Factory Stuff
private static InitialContextFactoryBuilder initctx_factory_builder = null;
/**
* Use this method for accessing initctx_factory_builder while
* inside an unsynchronized method.
*/
private static synchronized InitialContextFactoryBuilder
getInitialContextFactoryBuilder() {
return initctx_factory_builder;
}
/**
* Creates an initial context using the specified environment
* properties.
*<p>
* If an InitialContextFactoryBuilder has been installed,
* it is used to create the factory for creating the initial context.
* Otherwise, the class specified in the
* <tt>Context.INITIAL_CONTEXT_FACTORY</tt> environment property is used.
* Note that an initial context factory (an object that implements the
* InitialContextFactory interface) must be public and must have a
* public constructor that accepts no arguments.
*
* @param env The possibly null environment properties used when
* creating the context.
* @return A non-null initial context.
* @exception NoInitialContextException If the
* <tt>Context.INITIAL_CONTEXT_FACTORY</tt> property
* is not found or names a nonexistent
* class or a class that cannot be instantiated,
* or if the initial context could not be created for some other
* reason.
* @exception NamingException If some other naming exception was encountered.
* @see javax.naming.InitialContext
* @see javax.naming.directory.InitialDirContext
*/
public static Context getInitialContext(Hashtable<?,?> env)
throws NamingException {
InitialContextFactory factory;
InitialContextFactoryBuilder builder = getInitialContextFactoryBuilder();
if (builder == null) {
// No factory installed, use property
// Get initial context factory class name
String className = env != null ?
(String)env.get(Context.INITIAL_CONTEXT_FACTORY) : null;
if (className == null) {
NoInitialContextException ne = new NoInitialContextException(
"Need to specify class name in environment or system " +
"property, or as an applet parameter, or in an " +
"application resource file: " +
Context.INITIAL_CONTEXT_FACTORY);
throw ne;
}
try {
factory = (InitialContextFactory)
helper.loadClass(className).newInstance();
} catch(Exception e) {
NoInitialContextException ne =
new NoInitialContextException(
"Cannot instantiate class: " + className);
ne.setRootCause(e);
throw ne;
}
} else {
factory = builder.createInitialContextFactory(env);
}
return factory.getInitialContext(env);
}
/**
* Sets the InitialContextFactory builder to be builder.
*
*<p>
* The builder can only be installed if the executing thread is allowed by
* the security manager to do so. Once installed, the builder cannot
* be replaced.
* @param builder The initial context factory builder to install. If null,
* no builder is set.
* @exception SecurityException builder cannot be installed for security
* reasons.
* @exception NamingException builder cannot be installed for
* a non-security-related reason.
* @exception IllegalStateException If a builder was previous installed.
* @see #hasInitialContextFactoryBuilder
* @see java.lang.SecurityManager#checkSetFactory
*/
public static synchronized void setInitialContextFactoryBuilder(
InitialContextFactoryBuilder builder)
throws NamingException {
if (initctx_factory_builder != null)
throw new IllegalStateException(
"InitialContextFactoryBuilder already set");
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkSetFactory();
}
initctx_factory_builder = builder;
}
/**
* Determines whether an initial context factory builder has
* been set.
* @return true if an initial context factory builder has
* been set; false otherwise.
* @see #setInitialContextFactoryBuilder
*/
public static boolean hasInitialContextFactoryBuilder() {
return (getInitialContextFactoryBuilder() != null);
}
// ----- Continuation Context Stuff
/**
* Constant that holds the name of the environment property into
* which <tt>getContinuationContext()</tt> stores the value of its
* <tt>CannotProceedException</tt> parameter.
* This property is inherited by the continuation context, and may
* be used by that context's service provider to inspect the
* fields of the exception.
*<p>
* The value of this constant is "java.naming.spi.CannotProceedException".
*
* @see #getContinuationContext
* @since 1.3
*/
public static final String CPE = "java.naming.spi.CannotProceedException";
/**
* Creates a context in which to continue a context operation.
*<p>
* In performing an operation on a name that spans multiple
* namespaces, a context from one naming system may need to pass
* the operation on to the next naming system. The context
* implementation does this by first constructing a
* <code>CannotProceedException</code> containing information
* pinpointing how far it has proceeded. It then obtains a
* continuation context from JNDI by calling
* <code>getContinuationContext</code>. The context
* implementation should then resume the context operation by
* invoking the same operation on the continuation context, using
* the remainder of the name that has not yet been resolved.
*<p>
* Before making use of the <tt>cpe</tt> parameter, this method
* updates the environment associated with that object by setting
* the value of the property <a href="#CPE"><tt>CPE</tt></a>
* to <tt>cpe</tt>. This property will be inherited by the
* continuation context, and may be used by that context's
* service provider to inspect the fields of this exception.
*
* @param cpe
* The non-null exception that triggered this continuation.
* @return A non-null Context object for continuing the operation.
* @exception NamingException If a naming exception occurred.
*/
@SuppressWarnings("unchecked")
public static Context getContinuationContext(CannotProceedException cpe)
throws NamingException {
Hashtable<Object,Object> env = (Hashtable<Object,Object>)cpe.getEnvironment();
if (env == null) {
env = new Hashtable<>(7);
} else {
// Make a (shallow) copy of the environment.
env = (Hashtable<Object,Object>)env.clone();
}
env.put(CPE, cpe);
ContinuationContext cctx = new ContinuationContext(cpe, env);
return cctx.getTargetContext();
}
// ------------ State Factory Stuff
/**
* Retrieves the state of an object for binding.
* <p>
* Service providers that implement the <tt>DirContext</tt> interface
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