1 files changed, 509 insertions, 0 deletions
diff --git a/qpid/java/client/src/main/java/org/apache/qpid/naming/ReadOnlyContext.java b/qpid/java/client/src/main/java/org/apache/qpid/naming/ReadOnlyContext.java
new file mode 100644
index 0000000000..59ec4cfba7
--- /dev/null
+++ b/qpid/java/client/src/main/java/org/apache/qpid/naming/ReadOnlyContext.java
@@ -0,0 +1,509 @@
+/* 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.qpid.naming;
+
+import org.apache.qpid.jndi.NameParserImpl;
+
+import javax.naming.*;
+import javax.naming.spi.NamingManager;
+import java.io.Serializable;
+import java.util.*;
+
+/**
+ * Based on class from ActiveMQ.
+ * 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 OperationNotSupportedException.
+ * Each Context in the tree builds a cache of the entries in all sub-contexts
+ * to optimise the performance of lookup.
+ * </p>
+ * <p>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:</p>
+ * <code>
+ * Context componentContext = (Context)new InitialContext().lookup("java:comp");
+ * String envEntry = (String) componentContext.lookup("env/myEntry");
+ * String envEntry2 = (String) componentContext.lookup("env/myEntry2");
+ * </code>
+ */
+public class ReadOnlyContext implements Context, Serializable
+{
+    private static final long serialVersionUID = -5754338187296859149L;
+    protected static final NameParser nameParser = new NameParserImpl();
+
+    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 = false;
+    private String nameInNamespace = "";
+    public static final String SEPARATOR = "/";
+
+    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 = bindings;
+        treeBindings = new HashMap();
+        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 ReadOnlyContext.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 ReadOnlyContext.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 nameParser;
+    }
+
+    public NameParser getNameParser(String name) throws NamingException
+    {
+        return nameParser;
+    }
+
+    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 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 ReadOnlyContext.LocalNamingEnumeration
+    {
+        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 ReadOnlyContext.LocalNamingEnumeration
+    {
+        public Object next() throws NamingException
+        {
+            return nextElement();
+        }
+
+        public Object nextElement()
+        {
+            Map.Entry entry = getNext();
+
+            return new Binding((String) entry.getKey(), entry.getValue());
+        }
+    }
+}