namingcontext.java

业界著名的tomcat服务器的最新6.0的源代码。

    }


    /**
     * Retrieves the parser associated with the named context.
     * 
     * @param name the name of the context from which to get the parser
     * @return a name parser that can parse compound names into their atomic 
     * components
     * @exception NamingException if a naming exception is encountered
     */
    public NameParser getNameParser(String name)
        throws NamingException {
        return getNameParser(new CompositeName(name));
    }


    /**
     * Composes the name of this context with a name relative to this context.
     * <p>
     * Given a name (name) relative to this context, and the name (prefix) 
     * of this context relative to one of its ancestors, this method returns 
     * the composition of the two names using the syntax appropriate for the 
     * naming system(s) involved. That is, if name names an object relative 
     * to this context, the result is the name of the same object, but 
     * relative to the ancestor context. None of the names may be null.
     * 
     * @param name a name relative to this context
     * @param prefix the name of this context relative to one of its ancestors
     * @return the composition of prefix and name
     * @exception NamingException if a naming exception is encountered
     */
    public Name composeName(Name name, Name prefix)
        throws NamingException {
        prefix = (Name) prefix.clone();
        return prefix.addAll(name);
    }


    /**
     * Composes the name of this context with a name relative to this context.
     * 
     * @param name a name relative to this context
     * @param prefix the name of this context relative to one of its ancestors
     * @return the composition of prefix and name
     * @exception NamingException if a naming exception is encountered
     */
    public String composeName(String name, String prefix)
        throws NamingException {
        return prefix + "/" + name;
    }


    /**
     * Adds a new environment property to the environment of this context. If 
     * the property already exists, its value is overwritten.
     * 
     * @param propName the name of the environment property to add; may not 
     * be null
     * @param propVal the value of the property to add; may not be null
     * @exception NamingException if a naming exception is encountered
     */
    public Object addToEnvironment(String propName, Object propVal)
        throws NamingException {
        return env.put(propName, propVal);
    }


    /**
     * Removes an environment property from the environment of this context. 
     * 
     * @param propName the name of the environment property to remove; 
     * may not be null
     * @exception NamingException if a naming exception is encountered
     */
    public Object removeFromEnvironment(String propName)
        throws NamingException {
        return env.remove(propName);
    }


    /**
     * Retrieves the environment in effect for this context. See class 
     * description for more details on environment properties. 
     * The caller should not make any changes to the object returned: their 
     * effect on the context is undefined. The environment of this context 
     * may be changed using addToEnvironment() and removeFromEnvironment().
     * 
     * @return the environment of this context; never null
     * @exception NamingException if a naming exception is encountered
     */
    public Hashtable getEnvironment()
        throws NamingException {
        return env;
    }


    /**
     * Closes this context. This method releases this context's resources 
     * immediately, instead of waiting for them to be released automatically 
     * by the garbage collector.
     * This method is idempotent: invoking it on a context that has already 
     * been closed has no effect. Invoking any other method on a closed 
     * context is not allowed, and results in undefined behaviour.
     * 
     * @exception NamingException if a naming exception is encountered
     */
    public void close()
        throws NamingException {
        env.clear();
    }


    /**
     * Retrieves the full name of this context within its own namespace.
     * <p>
     * Many naming services have a notion of a "full name" for objects in 
     * their respective namespaces. For example, an LDAP entry has a 
     * distinguished name, and a DNS record has a fully qualified name. This 
     * method allows the client application to retrieve this name. The string 
     * returned by this method is not a JNDI composite name and should not be 
     * passed directly to context methods. In naming systems for which the 
     * notion of full name does not make sense, 
     * OperationNotSupportedException is thrown.
     * 
     * @return this context's name in its own namespace; never null
     * @exception OperationNotSupportedException if the naming system does 
     * not have the notion of a full name
     * @exception NamingException if a naming exception is encountered
     */
    public String getNameInNamespace()
        throws NamingException {
        throw  new OperationNotSupportedException
            (sm.getString("namingContext.noAbsoluteName"));
        //FIXME ?
    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Retrieves the named object.
     * 
     * @param name the name of the object to look up
     * @param resolveLinks If true, the links will be resolved
     * @return the object bound to name
     * @exception NamingException if a naming exception is encountered
     */
    protected Object lookup(Name name, boolean resolveLinks)
        throws NamingException {

        // Removing empty parts
        while ((!name.isEmpty()) && (name.get(0).length() == 0))
            name = name.getSuffix(1);
        if (name.isEmpty()) {
            // If name is empty, a newly allocated naming context is returned
            return new NamingContext(env, this.name, bindings);
        }
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (entry == null) {
            throw new NameNotFoundException
                (sm.getString("namingContext.nameNotBound", name.get(0)));
        }
        
        if (name.size() > 1) {
            // If the size of the name is greater that 1, then we go through a
            // number of subcontexts.
            if (entry.type != NamingEntry.CONTEXT) {
                throw new NamingException
                    (sm.getString("namingContext.contextExpected"));
            }
            return ((Context) entry.value).lookup(name.getSuffix(1));
        } else {
            if ((resolveLinks) && (entry.type == NamingEntry.LINK_REF)) {
                String link = ((LinkRef) entry.value).getLinkName();
                if (link.startsWith(".")) {
                    // Link relative to this context
                    return lookup(link.substring(1));
                } else {
                    return (new InitialContext(env)).lookup(link);
                }
            } else if (entry.type == NamingEntry.REFERENCE) {
                try {
                    Object obj = NamingManager.getObjectInstance
                        (entry.value, name, this, env);
                    if (obj != null) {
                        entry.value = obj;
                        entry.type = NamingEntry.ENTRY;
                    }
                    return obj;
                } catch (NamingException e) {
                    throw e;
                } catch (Exception e) {
                    log.warn(sm.getString
                             ("namingContext.failResolvingReference"), e);
                    throw new NamingException(e.getMessage());
                }
            } else {
                return entry.value;
            }
        }
        
    }


    /**
     * Binds a name to an object. All intermediate contexts and the target 
     * context (that named by all but terminal atomic component of the name) 
     * must already exist.
     * 
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @param rebind if true, then perform a rebind (ie, overwrite)
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if object did not supply all 
     * mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    protected void bind(Name name, Object obj, boolean rebind)
        throws NamingException {
        
        checkWritable();
        
        while ((!name.isEmpty()) && (name.get(0).length() == 0))
            name = name.getSuffix(1);
        if (name.isEmpty())
            throw new NamingException
                (sm.getString("namingContext.invalidName"));
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (name.size() > 1) {
            if (entry == null) {
                throw new NameNotFoundException
                    (sm.getString("namingContext.nameNotBound", name.get(0)));
            }
            if (entry.type == NamingEntry.CONTEXT) {
                if (rebind) {
                    ((Context) entry.value).rebind(name.getSuffix(1), obj);
                } else {
                    ((Context) entry.value).bind(name.getSuffix(1), obj);
                }
            } else {
                throw new NamingException
                    (sm.getString("namingContext.contextExpected"));
            }
        } else {
            if ((!rebind) && (entry != null)) {
                throw new NameAlreadyBoundException
                    (sm.getString("namingContext.alreadyBound", name.get(0)));
            } else {
                // Getting the type of the object and wrapping it within a new
                // NamingEntry
                Object toBind = 
                    NamingManager.getStateToBind(obj, name, this, env);
                if (toBind instanceof Context) {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.CONTEXT);
                } else if (toBind instanceof LinkRef) {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.LINK_REF);
                } else if (toBind instanceof Reference) {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.REFERENCE);
                } else if (toBind instanceof Referenceable) {
                    toBind = ((Referenceable) toBind).getReference();
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.REFERENCE);
                } else {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.ENTRY);
                }
                bindings.put(name.get(0), entry);
            }
        }
        
    }


    /**
     * Returns true if writing is allowed on this context.
     */
    protected boolean isWritable() {
        return ContextAccessController.isWritable(name);
    }


    /**
     * Throws a naming exception is Context is not writable.
     */
    protected void checkWritable() 
        throws NamingException {
        if (!isWritable())
            throw new NamingException(sm.getString("namingContext.readOnly"));
    }


}