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/**
 * 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.activemq.jndi;

import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import javax.naming.Binding;
import javax.naming.CompositeName;
import javax.naming.Context;
import javax.naming.LinkRef;
import javax.naming.Name;
import javax.naming.NameClassPair;
import javax.naming.NameNotFoundException;
import javax.naming.NameParser;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.NotContextException;
import javax.naming.OperationNotSupportedException;
import javax.naming.Reference;
import javax.naming.spi.NamingManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A read-only Context 

This version assumes it and all its subcontext are * read-only and any attempt to modify (e.g. through bind) will result in an * OperationNotSupportedException. Each Context in the tree builds a cache of * the entries in all sub-contexts to optimise the performance of lookup. *

*

* This implementation is intended to optimise the performance of lookup(String) * to about the level of a HashMap get. It has been observed that the scheme * resolution phase performed by the JVM takes considerably longer, so for * optimum performance lookups should be coded like: *

* * Context componentContext = (Context)new InitialContext().lookup("java:comp"); * String envEntry = (String) componentContext.lookup("env/myEntry"); * String envEntry2 = (String) componentContext.lookup("env/myEntry2"); * * * $Date: 2005/08/27 03:52:39 $ */ @SuppressWarnings("unchecked") public class ReadOnlyContext implements Context, Serializable { private static final Logger LOG = LoggerFactory.getLogger(ReadOnlyContext.class); public static final String SEPARATOR = "/"; protected static final NameParser NAME_PARSER = new NameParserImpl(); private static final long serialVersionUID = -5754338187296859149L; protected final Hashtable environment; // environment for this context protected final Map bindings; // bindings at my level protected final Map treeBindings; // all bindings under me private boolean frozen; private String nameInNamespace = ""; public ReadOnlyContext() { environment = new Hashtable(); bindings = new HashMap(); treeBindings = new HashMap(); } public ReadOnlyContext(Hashtable env) { if (env == null) { this.environment = new Hashtable(); } else { this.environment = new Hashtable(env); } this.bindings = Collections.EMPTY_MAP; this.treeBindings = Collections.EMPTY_MAP; } public ReadOnlyContext(Hashtable environment, Map bindings) { if (environment == null) { this.environment = new Hashtable(); } else { this.environment = new Hashtable(environment); } this.bindings = new HashMap(); treeBindings = new HashMap(); if (bindings != null) { for (Map.Entry binding : bindings.entrySet()) { try { internalBind(binding.getKey(), binding.getValue()); } catch (Throwable e) { LOG.error("Failed to bind " + binding.getKey() + "=" + binding.getValue(), e); } } } frozen = true; } public ReadOnlyContext(Hashtable environment, Map bindings, String nameInNamespace) { this(environment, bindings); this.nameInNamespace = nameInNamespace; } protected ReadOnlyContext(ReadOnlyContext clone, Hashtable env) { this.bindings = clone.bindings; this.treeBindings = clone.treeBindings; this.environment = new Hashtable(env); } protected ReadOnlyContext(ReadOnlyContext clone, Hashtable env, String nameInNamespace) { this(clone, env); this.nameInNamespace = nameInNamespace; } public void freeze() { frozen = true; } boolean isFrozen() { return frozen; } /** * internalBind is intended for use only during setup or possibly by * suitably synchronized superclasses. It binds every possible lookup into a * map in each context. To do this, each context strips off one name segment * and if necessary creates a new context for it. Then it asks that context * to bind the remaining name. It returns a map containing all the bindings * from the next context, plus the context it just created (if it in fact * created it). (the names are suitably extended by the segment originally * lopped off). * * @param name * @param value * @return * @throws javax.naming.NamingException */ protected Map internalBind(String name, Object value) throws NamingException { assert name != null && name.length() > 0; assert !frozen; Map newBindings = new HashMap(); int pos = name.indexOf('/'); if (pos == -1) { if (treeBindings.put(name, value) != null) { throw new NamingException("Something already bound at " + name); } bindings.put(name, value); newBindings.put(name, value); } else { String segment = name.substring(0, pos); assert segment != null; assert !segment.equals(""); Object o = treeBindings.get(segment); if (o == null) { o = newContext(); treeBindings.put(segment, o); bindings.put(segment, o); newBindings.put(segment, o); } else if (!(o instanceof ReadOnlyContext)) { throw new NamingException("Something already bound where a subcontext should go"); } ReadOnlyContext readOnlyContext = (ReadOnlyContext)o; String remainder = name.substring(pos + 1); Map subBindings = readOnlyContext.internalBind(remainder, value); for (Iterator iterator = subBindings.entrySet().iterator(); iterator.hasNext();) { Map.Entry entry = (Map.Entry)iterator.next(); String subName = segment + "/" + (String)entry.getKey(); Object bound = entry.getValue(); treeBindings.put(subName, bound); newBindings.put(subName, bound); } } return newBindings; } protected ReadOnlyContext newContext() { return new ReadOnlyContext(); } public Object addToEnvironment(String propName, Object propVal) throws NamingException { return environment.put(propName, propVal); } public Hashtable getEnvironment() throws NamingException { return (Hashtable)environment.clone(); } public Object removeFromEnvironment(String propName) throws NamingException { return environment.remove(propName); } public Object lookup(String name) throws NamingException { if (name.length() == 0) { return this; } Object result = treeBindings.get(name); if (result == null) { result = bindings.get(name); } if (result == null) { int pos = name.indexOf(':'); if (pos > 0) { String scheme = name.substring(0, pos); Context ctx = NamingManager.getURLContext(scheme, environment); if (ctx == null) { throw new NamingException("scheme " + scheme + " not recognized"); } return ctx.lookup(name); } else { // Split out the first name of the path // and look for it in the bindings map. CompositeName path = new CompositeName(name); if (path.size() == 0) { return this; } else { String first = path.get(0); Object obj = bindings.get(first); if (obj == null) { throw new NameNotFoundException(name); } else if (obj instanceof Context && path.size() > 1) { Context subContext = (Context)obj; obj = subContext.lookup(path.getSuffix(1)); } return obj; } } } if (result instanceof LinkRef) { LinkRef ref = (LinkRef)result; result = lookup(ref.getLinkName()); } if (result instanceof Reference) { try { result = NamingManager.getObjectInstance(result, null, null, this.environment); } catch (NamingException e) { throw e; } catch (Exception e) { throw (NamingException)new NamingException("could not look up : " + name).initCause(e); } } if (result instanceof ReadOnlyContext) { String prefix = getNameInNamespace(); if (prefix.length() > 0) { prefix = prefix + SEPARATOR; } result = new ReadOnlyContext((ReadOnlyContext)result, environment, prefix + name); } return result; } public Object lookup(Name name) throws NamingException { return lookup(name.toString()); } public Object lookupLink(String name) throws NamingException { return lookup(name); } public Name composeName(Name name, Name prefix) throws NamingException { Name result = (Name)prefix.clone(); result.addAll(name); return result; } public String composeName(String name, String prefix) throws NamingException { CompositeName result = new CompositeName(prefix); result.addAll(new CompositeName(name)); return result.toString(); } public NamingEnumeration list(String name) throws NamingException { Object o = lookup(name); if (o == this) { return new ListEnumeration(); } else if (o instanceof Context) { return ((Context)o).list(""); } else { throw new NotContextException(); } } public NamingEnumeration listBindings(String name) throws NamingException { Object o = lookup(name); if (o == this) { return new ListBindingEnumeration(); } else if (o instanceof Context) { return ((Context)o).listBindings(""); } else { throw new NotContextException(); } } public Object lookupLink(Name name) throws NamingException { return lookupLink(name.toString()); } public NamingEnumeration list(Name name) throws NamingException { return list(name.toString()); } public NamingEnumeration listBindings(Name name) throws NamingException { return listBindings(name.toString()); } public void bind(Name name, Object obj) throws NamingException { throw new OperationNotSupportedException(); } public void bind(String name, Object obj) throws NamingException { throw new OperationNotSupportedException(); } public void close() throws NamingException { // ignore } public Context createSubcontext(Name name) throws NamingException { throw new OperationNotSupportedException(); } public Context createSubcontext(String name) throws NamingException { throw new OperationNotSupportedException(); } public void destroySubcontext(Name name) throws NamingException { throw new OperationNotSupportedException(); } public void destroySubcontext(String name) throws NamingException { throw new OperationNotSupportedException(); } public String getNameInNamespace() throws NamingException { return nameInNamespace; } public NameParser getNameParser(Name name) throws NamingException { return NAME_PARSER; } public NameParser getNameParser(String name) throws NamingException { return NAME_PARSER; } public void rebind(Name name, Object obj) throws NamingException { throw new OperationNotSupportedException(); } public void rebind(String name, Object obj) throws NamingException { throw new OperationNotSupportedException(); } public void rename(Name oldName, Name newName) throws NamingException { throw new OperationNotSupportedException(); } public void rename(String oldName, String newName) throws NamingException { throw new OperationNotSupportedException(); } public void unbind(Name name) throws NamingException { throw new OperationNotSupportedException(); } public void unbind(String name) throws NamingException { throw new OperationNotSupportedException(); } private abstract class LocalNamingEnumeration implements NamingEnumeration { private final Iterator i = bindings.entrySet().iterator(); public boolean hasMore() throws NamingException { return i.hasNext(); } public boolean hasMoreElements() { return i.hasNext(); } protected Map.Entry getNext() { return (Map.Entry)i.next(); } public void close() throws NamingException { } } private class ListEnumeration extends LocalNamingEnumeration { ListEnumeration() { } public Object next() throws NamingException { return nextElement(); } public Object nextElement() { Map.Entry entry = getNext(); return new NameClassPair((String)entry.getKey(), entry.getValue().getClass().getName()); } } private class ListBindingEnumeration extends LocalNamingEnumeration { ListBindingEnumeration() { } public Object next() throws NamingException { return nextElement(); } public Object nextElement() { Map.Entry entry = getNext(); return new Binding((String)entry.getKey(), entry.getValue()); } } }




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