org.apache.activemq.artemis.jndi.ReadOnlyContext Maven / Gradle / Ivy

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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.artemis.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.apache.activemq.artemis.core.client.ActiveMQClientLogger;

/**
 * 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");
 * 
 */
@SuppressWarnings("unchecked")
public class ReadOnlyContext implements Context, Serializable
{
   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)
            {
               ActiveMQClientLogger.LOGGER.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());
      }
   }
}