/**
* 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;
/**
* 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>
*
* @version $Revision: 1.2 $ $Date: 2005/08/27 03:52:39 $
*/
@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<String, Object>();
bindings = new HashMap<String, Object>();
treeBindings = new HashMap<String, Object>();
}
public ReadOnlyContext(Hashtable env) {
if (env == null) {
this.environment = new Hashtable<String, Object>();
} else {
this.environment = new Hashtable<String, Object>(env);
}
this.bindings = Collections.EMPTY_MAP;
this.treeBindings = Collections.EMPTY_MAP;
}
public ReadOnlyContext(Hashtable environment, Map<String, Object> bindings) {
if (environment == null) {
this.environment = new Hashtable<String, Object>();
} else {
this.environment = new Hashtable<String, Object>(environment);
}
this.bindings = bindings;
treeBindings = new HashMap<String, Object>();
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<String, Object>(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;
}
/**
* 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<String, Object> internalBind(String name, Object value) throws NamingException {
assert name != null && name.length() > 0;
assert !frozen;
Map<String, Object> newBindings = new HashMap<String, Object>();
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<String, Object> 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<String, Object> getEnvironment() throws NamingException {
return (Hashtable<String, Object>)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 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());
}
}
}