content: /*
   * 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 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 java.io.Serializable;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Hashtable;
  import java.util.Iterator;
  import java.util.Map;
  
  import org.apache.activemq.artemis.core.client.ActiveMQClientLogger;
  
  /**
   * A read-only Context
   * <p>
   * This version assumes it and all its subcontext are read-only and any attempt to modify (e.g. through bind) will
   * result in an {@link OperationNotSupportedException}. Each Context in the tree builds a cache of the entries in all
   * sub-contexts to optimise the performance of lookup.
   * <p>
   * This implementation is intended to optimise the performance of {@link #lookup(String)} to about the level of a
   * {@link HashMap#get(Object)}. 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:
   * <pre>
   * {@code
   * Context componentContext = (Context)new InitialContext().lookup("java:comp");
   * String envEntry = (String) componentContext.lookup("env/myEntry");
   * String envEntry2 = (String) componentContext.lookup("env/myEntry2");
   * }</pre>
   */
  @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<String, Object> environment; // environment for this context
     protected final Map<String, Object> bindings; // bindings at my level
     protected final Map<String, Object> 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.emptyMap();
        this.treeBindings = Collections.emptyMap();
     }
  
     public ReadOnlyContext(Hashtable environment, Map<String, Object> 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<String, Object> binding : bindings.entrySet()) {
              try {
                 internalBind(binding.getKey(), binding.getValue());
              } catch (Throwable e) {
                 ActiveMQClientLogger.LOGGER.failedToBind(binding.getKey(), binding.getValue().toString(), e);
              }
           }
        }
        frozen = true;
     }
  
     public ReadOnlyContext(Hashtable environment, Map<String, Object> 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<String, Object> env, String nameInNamespace) {
        this(clone, env);
        this.nameInNamespace = nameInNamespace;
     }
  
     public void freeze() {
        frozen = true;
     }
  
     boolean isFrozen() {
        return frozen;
     }
  
     /**
      * This 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).
      */
     protected Map<String, Object> internalBind(String name, Object value) throws NamingException {
        assert name != null && !name.isEmpty();
        assert !frozen;
  
        Map<String, Object> 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.isEmpty();
           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<String, Object> subBindings = readOnlyContext.internalBind(remainder, value);
           for (Map.Entry<String, Object> entry : subBindings.entrySet()) {
              String subName = segment + "/" + entry.getKey();
              Object bound = entry.getValue();
              treeBindings.put(subName, bound);
              newBindings.put(subName, bound);
           }
        }
        return newBindings;
     }
  
     protected ReadOnlyContext newContext() {
        return new ReadOnlyContext();
     }
  
     @Override
     public Object addToEnvironment(String propName, Object propVal) throws NamingException {
        return environment.put(propName, propVal);
     }
  
     @Override
     public Hashtable<String, Object> getEnvironment() throws NamingException {
        return (Hashtable<String, Object>) environment.clone();
     }
  
     @Override
     public Object removeFromEnvironment(String propName) throws NamingException {
        return environment.remove(propName);
     }
  
     @Override
     public Object lookup(String name) throws NamingException {
        if (name.isEmpty()) {
           return this;
        }
        Object result = treeBindings.get(name);
        if (result == null) {
           result = bindings.get(name);
        }
        if (result == null) {
           int pos = name.indexOf(':');
           if (pos > 0 && !name.contains("::")) {
              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.isEmpty()) {
                 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 subContext && path.size() > 1) {
                    obj = subContext.lookup(path.getSuffix(1));
                 }
                 return obj;
              }
           }
        }
        if (result instanceof LinkRef ref) {
           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 context) {
           String prefix = getNameInNamespace();
           if (!prefix.isEmpty()) {
              prefix = prefix + SEPARATOR;
           }
           result = new ReadOnlyContext(context, environment, prefix + name);
        }
        return result;
     }
  
     @Override
     public Object lookup(Name name) throws NamingException {
        return lookup(name.toString());
     }
  
     @Override
     public Object lookupLink(String name) throws NamingException {
        return lookup(name);
     }
  
     @Override
     public Name composeName(Name name, Name prefix) throws NamingException {
        Name result = (Name) prefix.clone();
        result.addAll(name);
        return result;
     }
  
     @Override
     public String composeName(String name, String prefix) throws NamingException {
        CompositeName result = new CompositeName(prefix);
        result.addAll(new CompositeName(name));
        return result.toString();
     }
  
     @Override
     public NamingEnumeration<NameClassPair> list(String name) throws NamingException {
        Object o = lookup(name);
        if (o == this) {
           return new ListEnumeration();
        } else if (o instanceof Context context) {
           return context.list("");
        } else {
           throw new NotContextException();
        }
     }
  
     @Override
     public NamingEnumeration<Binding> listBindings(String name) throws NamingException {
        Object o = lookup(name);
        if (o == this) {
           return new ListBindingEnumeration();
        } else if (o instanceof Context context) {
           return context.listBindings("");
        } else {
           throw new NotContextException();
        }
     }
  
     @Override
     public Object lookupLink(Name name) throws NamingException {
        return lookupLink(name.toString());
     }
  
     @Override
     public NamingEnumeration<NameClassPair> list(Name name) throws NamingException {
        return list(name.toString());
     }
  
     @Override
     public NamingEnumeration<Binding> listBindings(Name name) throws NamingException {
        return listBindings(name.toString());
     }
  
     @Override
     public void bind(Name name, Object obj) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void bind(String name, Object obj) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void close() throws NamingException {
        // ignore
     }
  
     @Override
     public Context createSubcontext(Name name) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public Context createSubcontext(String name) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void destroySubcontext(Name name) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void destroySubcontext(String name) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public String getNameInNamespace() throws NamingException {
        return nameInNamespace;
     }
  
     @Override
     public NameParser getNameParser(Name name) throws NamingException {
        return NAME_PARSER;
     }
  
     @Override
     public NameParser getNameParser(String name) throws NamingException {
        return NAME_PARSER;
     }
  
     @Override
     public void rebind(Name name, Object obj) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void rebind(String name, Object obj) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void rename(Name oldName, Name newName) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void rename(String oldName, String newName) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void unbind(Name name) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     @Override
     public void unbind(String name) throws NamingException {
        throw new OperationNotSupportedException();
     }
  
     private abstract class LocalNamingEnumeration implements NamingEnumeration {
  
        private final Iterator<Map.Entry<String, Object>> i = bindings.entrySet().iterator();
  
        @Override
        public boolean hasMore() throws NamingException {
           return i.hasNext();
        }
  
        @Override
        public boolean hasMoreElements() {
           return i.hasNext();
        }
  
        protected Map.Entry<String, Object> getNext() {
           return i.next();
        }
  
        @Override
        public void close() throws NamingException {
        }
     }
  
     private class ListEnumeration extends LocalNamingEnumeration {
  
        ListEnumeration() {
        }
  
        @Override
        public Object next() throws NamingException {
           return nextElement();
        }
  
        @Override
        public Object nextElement() {
           Map.Entry<String, Object> entry = getNext();
           return new NameClassPair(entry.getKey(), entry.getValue().getClass().getName());
        }
     }
  
     private class ListBindingEnumeration extends LocalNamingEnumeration {
  
        ListBindingEnumeration() {
        }
  
        @Override
        public Object next() throws NamingException {
           return nextElement();
        }
  
        @Override
        public Object nextElement() {
           Map.Entry<String, Object> entry = getNext();
           return new Binding(entry.getKey(), entry.getValue());
        }
     }
  }
  