/**
*
* Copyright 2003-2004 The Apache Software Foundation
*
* Licensed 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.geronimo.naming.java;
import java.util.Collections;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.io.Serializable;
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.InitialContext;
import javax.naming.spi.NamingManager;
import org.apache.geronimo.naming.reference.SimpleReference;
import org.apache.geronimo.naming.reference.KernelAwareReference;
import org.apache.geronimo.naming.reference.ClassLoaderAwareReference;
import org.apache.geronimo.kernel.Kernel;
/**
* A read-only Context in the java: namespace.
* <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 $Rev: 355877 $ $Date: 2005-12-11 03:48:27 +0100 (Sun, 11 Dec 2005) $
*/
public class ReadOnlyContext implements Context, Serializable {
protected final Hashtable env; // environment for this context
protected final Map bindings; // bindings at my level
protected final Map treeBindings; // all bindings under me
private boolean frozen = false;
public ReadOnlyContext() {
env = new Hashtable();
bindings = new HashMap();
treeBindings = new HashMap();
}
ReadOnlyContext(Hashtable env) {
if (env == null) {
this.env = new Hashtable();
} else {
this.env = new Hashtable(env);
}
this.bindings = Collections.EMPTY_MAP;
this.treeBindings = Collections.EMPTY_MAP;
}
protected ReadOnlyContext(ReadOnlyContext clone, Hashtable env) {
this.bindings = clone.bindings;
this.treeBindings = clone.treeBindings;
this.env = new Hashtable(env);
}
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 + "/" + entry.getKey();
Object bound = entry.getValue();
treeBindings.put(subName, bound);
newBindings.put(subName, bound);
}
}
return newBindings;
}
protected ReadOnlyContext newContext() {
return new ReadOnlyContext();
}
public void setKernel(Kernel kernel) {
for (Iterator iterator = treeBindings.values().iterator(); iterator.hasNext();) {
Object o = iterator.next();
if (o instanceof KernelAwareReference) {
((KernelAwareReference) o).setKernel(kernel);
}
}
}
public void setClassLoader(ClassLoader classLoader) {
for (Iterator iterator = treeBindings.values().iterator(); iterator.hasNext();) {
Object o = iterator.next();
if (o instanceof ClassLoaderAwareReference) {
((ClassLoaderAwareReference) o).setClassLoader(classLoader);
}
}
}
public Object addToEnvironment(String propName, Object propVal) throws NamingException {
return env.put(propName, propVal);
}
public Hashtable getEnvironment() throws NamingException {
return (Hashtable) env.clone();
}
public Object removeFromEnvironment(String propName) throws NamingException {
return env.remove(propName);
}
public Object lookup(String name) throws NamingException {
if (name.length() == 0) {
return this;
}
Object result = treeBindings.get(name);
if (result == null) {
if (name.indexOf(':') > 0) {
Context ctx = new InitialContext();
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 {
Object obj = bindings.get(path.get(0));
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 SimpleReference) {
try {
result = ((SimpleReference) result).getContent();
} catch (Exception e) {
throw (NamingException)new NamingException("could not look up : " + name).initCause(e);
}
}
if (result instanceof LinkRef) {
LinkRef ref = (LinkRef) result;
result = lookup(ref.getLinkName());
}
if (result instanceof Reference) {
try {
result = NamingManager.getObjectInstance(result, null, null, this.env);
} catch (NamingException e) {
throw e;
} catch (Exception e) {
throw (NamingException)new NamingException("could not look up : " + name).initCause(e);
}
}
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 {
throw new OperationNotSupportedException();
}
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 {
throw new OperationNotSupportedException();
}
public NameParser getNameParser(Name name) throws NamingException {
throw new OperationNotSupportedException();
}
public NameParser getNameParser(String name) throws NamingException {
throw new OperationNotSupportedException();
}
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 {
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 {
public Object next() throws NamingException {
return nextElement();
}
public Object nextElement() {
Map.Entry entry = getNext();
return new Binding((String) entry.getKey(), entry.getValue());
}
}
}