Java example source code file (ComponentContext.java)
The ComponentContext.java Java example source code
/*
* Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* questions.
*/
package com.sun.jndi.toolkit.ctx;
import javax.naming.*;
import javax.naming.spi.ResolveResult;
/**
* Provides implementation of p_* operations using
* c_* operations provided by subclasses.
*
* Clients: deal only with names for its own naming service. Must
* provide implementations for c_* methods, and for p_parseComponent()
* and the c_*_nns methods if the defaults are not appropriate.
*
* @author Rosanna Lee
* @author Scott Seligman
*/
public abstract class ComponentContext extends PartialCompositeContext {
private static int debug = 0;
protected ComponentContext() {
_contextType = _COMPONENT;
}
// ------ Abstract methods whose implementation are provided by subclass
/* Equivalent methods in Context interface */
protected abstract Object c_lookup(Name name, Continuation cont)
throws NamingException;
protected abstract Object c_lookupLink(Name name, Continuation cont)
throws NamingException;
protected abstract NamingEnumeration<NameClassPair> c_list(Name name,
Continuation cont) throws NamingException;
protected abstract NamingEnumeration<Binding> c_listBindings(Name name,
Continuation cont) throws NamingException;
protected abstract void c_bind(Name name, Object obj, Continuation cont)
throws NamingException;
protected abstract void c_rebind(Name name, Object obj, Continuation cont)
throws NamingException;
protected abstract void c_unbind(Name name, Continuation cont)
throws NamingException;
protected abstract void c_destroySubcontext(Name name, Continuation cont)
throws NamingException;
protected abstract Context c_createSubcontext(Name name,
Continuation cont) throws NamingException;
protected abstract void c_rename(Name oldname, Name newname,
Continuation cont) throws NamingException;
protected abstract NameParser c_getNameParser(Name name, Continuation cont)
throws NamingException;
// ------ Methods that may need to be overridden by subclass
/* Parsing method */
/**
* Determines which of the first components of 'name' belong
* to this naming system.
* If no components belong to this naming system, return
* the empty name (new CompositeName()) as the head,
* and the entire name as the tail.
*
* The default implementation supports strong separation.
* If the name is empty or if the first component is empty,
* head is the empty name and tail is the entire name.
* (This means that this context does not have any name to work with).
* Otherwise, it returns the first component as head, and the rest of
* the components as tail.
*
* Subclass should override this method according its own policies.
*
* For example, a weakly separated system with dynamic boundary
* determination would simply return as head 'name'.
* A weakly separated with static boundary
* determination would select the components in the front of 'name'
* that conform to some syntax rules. (e.g. in X.500 syntax, perhaps
* select front components that have a equal sign).
* If none conforms, return an empty name.
*/
protected HeadTail p_parseComponent(Name name, Continuation cont)
throws NamingException {
int separator;
// if no name to parse, or if we're already at boundary
if (name.isEmpty() || name.get(0).equals("")) {
separator = 0;
} else {
separator = 1;
}
Name head, tail;
if (name instanceof CompositeName) {
head = name.getPrefix(separator);
tail = name.getSuffix(separator);
} else {
// treat like compound name
head = new CompositeName().add(name.toString());
tail = null;
}
if (debug > 2) {
System.err.println("ORIG: " + name);
System.err.println("PREFIX: " + name);
System.err.println("SUFFIX: " + null);
}
return new HeadTail(head, tail);
}
/* Resolution method for supporting federation */
/**
* Resolves the nns for 'name' when the named context is acting
* as an intermediate context.
*
* For a system that supports only junctions, this would be
* equilvalent to
* c_lookup(name, cont);
* because for junctions, an intermediate slash simply signifies
* a syntactic separator.
*
* For a system that supports only implicit nns, this would be
* equivalent to
* c_lookup_nns(name, cont);
* because for implicit nns, a slash always signifies the implicit nns,
* regardless of whether it is intermediate or trailing.
*
* By default this method supports junctions, and also allows for an
* implicit nns to be dynamically determined through the use of the
* "nns" reference (see c_processJunction_nns()).
* Contexts that implement implicit nns directly should provide an
* appropriate override.
*
* A junction, by definition, is a binding of a name in one
* namespace to an object in another. The default implementation
* of this method detects the crossover into another namespace
* using the following heuristic: there is a junction when "name"
* resolves to a context that is not an instance of
* this.getClass(). Contexts supporting junctions for which this
* heuristic is inappropriate should override this method.
*/
protected Object c_resolveIntermediate_nns(Name name, Continuation cont)
throws NamingException {
try {
final Object obj = c_lookup(name, cont);
// Do not append "" to Continuation 'cont' even if set
// because the intention is to ignore the nns
if (obj != null && getClass().isInstance(obj)) {
// If "obj" is in the same type as this object, it must
// not be a junction. Continue the lookup with "/".
cont.setContinueNNS(obj, name, this);
return null;
} else if (obj != null && !(obj instanceof Context)) {
// obj is not even a context, so try to find its nns
// dynamically by constructing a Reference containing obj.
RefAddr addr = new RefAddr("nns") {
public Object getContent() {
return obj;
}
private static final long serialVersionUID =
-8831204798861786362L;
};
Reference ref = new Reference("java.lang.Object", addr);
// Resolved name has trailing slash to indicate nns
CompositeName resName = (CompositeName)name.clone();
resName.add(""); // add trailing slash
// Set continuation leave it to
// PartialCompositeContext.getPCContext() to throw CPE.
// Do not use setContinueNNS() because we've already
// consumed "/" (i.e., moved it to resName).
cont.setContinue(ref, resName, this);
return null;
} else {
// Consume "/" and continue
return obj;
}
} catch (NamingException e) {
e.appendRemainingComponent(""); // add nns back
throw e;
}
}
/* Equivalent of Context Methods for supporting nns */
// The following methods are called when the Context methods
// are invoked with a name that has a trailing slash.
// For naming systems that support implicit nns,
// the trailing slash signifies the implicit nns.
// For such naming systems, override these c_*_nns methods.
//
// For naming systems that do not support implicit nns, the
// default implementations here throw an exception. See
// c_processJunction_nns() for details.
protected Object c_lookup_nns(Name name, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
return null;
}
protected Object c_lookupLink_nns(Name name, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
return null;
}
protected NamingEnumeration<NameClassPair> c_list_nns(Name name,
Continuation cont) throws NamingException {
c_processJunction_nns(name, cont);
return null;
}
protected NamingEnumeration<Binding> c_listBindings_nns(Name name,
Continuation cont) throws NamingException {
c_processJunction_nns(name, cont);
return null;
}
protected void c_bind_nns(Name name, Object obj, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
}
protected void c_rebind_nns(Name name, Object obj, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
}
protected void c_unbind_nns(Name name, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
}
protected Context c_createSubcontext_nns(Name name,
Continuation cont) throws NamingException {
c_processJunction_nns(name, cont);
return null;
}
protected void c_destroySubcontext_nns(Name name, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
}
protected void c_rename_nns(Name oldname, Name newname, Continuation cont)
throws NamingException {
c_processJunction_nns(oldname, cont);
}
protected NameParser c_getNameParser_nns(Name name, Continuation cont)
throws NamingException {
c_processJunction_nns(name, cont);
return null;
}
// ------ internal method used by ComponentContext
/**
* Locates the nns using the default policy. This policy fully
* handles junctions, but otherwise throws an exception when an
* attempt is made to resolve an implicit nns.
*
* The default policy is as follows: If there is a junction in
* the namespace, then resolve to the junction and continue the
* operation there (thus deferring to that context to find its own
* nns). Otherwise, resolve as far as possible and then throw
* CannotProceedException with the resolved object being a reference:
* the address type is "nns", and the address contents is this
* context.
*
* For example, when c_bind_nns(name, obj, ...) is invoked, the
* caller is attempting to bind the object "obj" to the nns of
* "name". If "name" is a junction, it names an object in another
* naming system that (presumably) has an nns. c_bind_nns() will
* first resolve "name" to a context and then attempt to continue
* the bind operation there, (thus binding to the nns of the
* context named by "name"). If "name" is empty then throw an
* exception, since this context does not by default support an
* implicit nns.
*
* To implement a context that does support an implicit nns, it is
* necessary to override this default policy. This is done by
* overriding the c_*_nns() methods (which each call this method
* by default).
*/
protected void c_processJunction_nns(Name name, Continuation cont)
throws NamingException
{
if (name.isEmpty()) {
// Construct a new Reference that contains this context.
RefAddr addr = new RefAddr("nns") {
public Object getContent() {
return ComponentContext.this;
}
private static final long serialVersionUID =
-1389472957988053402L;
};
Reference ref = new Reference("java.lang.Object", addr);
// Set continuation leave it to PartialCompositeContext.getPCContext()
// to throw the exception.
// Do not use setContinueNNS() because we've are
// setting relativeResolvedName to "/".
cont.setContinue(ref, _NNS_NAME, this);
return;
}
try {
// lookup name to continue operation in nns
Object target = c_lookup(name, cont);
if (cont.isContinue())
cont.appendRemainingComponent("");
else {
cont.setContinueNNS(target, name, this);
}
} catch (NamingException e) {
e.appendRemainingComponent(""); // add nns back
throw e;
}
}
protected static final byte USE_CONTINUATION = 1;
protected static final byte TERMINAL_COMPONENT = 2;
protected static final byte TERMINAL_NNS_COMPONENT = 3;
/**
* Determine whether 'name' is a terminal component in
* this naming system.
* If so, return status indicating so, so that caller
* can perform context operation on this name.
*
* If not, then the first component(s) of 'name' names
* an intermediate context. In that case, resolve these components
* and set Continuation to be the object named.
*
* see test cases at bottom of file.
*/
protected HeadTail p_resolveIntermediate(Name name, Continuation cont)
throws NamingException {
int ret = USE_CONTINUATION;
cont.setSuccess(); // initialize
HeadTail p = p_parseComponent(name, cont);
Name tail = p.getTail();
Name head = p.getHead();
if (tail == null || tail.isEmpty()) {
//System.out.println("terminal : " + head);
ret = TERMINAL_COMPONENT;
} else if (!tail.get(0).equals("")) {
// tail does not begin with "/"
/*
if (head.isEmpty()) {
// Context could not find name that it can use
// illegal syntax error or name not found
//System.out.println("nnf exception : " + head);
NamingException e = new NameNotFoundException();
cont.setError(this, name);
throw cont.fillInException(e);
} else {
*/
// head is being used as intermediate context,
// resolve head and set Continuation with tail
try {
Object obj = c_resolveIntermediate_nns(head, cont);
//System.out.println("resInter : " + head + "=" + obj);
if (obj != null)
cont.setContinue(obj, head, this, tail);
else if (cont.isContinue()) {
checkAndAdjustRemainingName(cont.getRemainingName());
cont.appendRemainingName(tail);
}
} catch (NamingException e) {
checkAndAdjustRemainingName(e.getRemainingName());
e.appendRemainingName(tail);
throw e;
}
/*
}
*/
} else {
// tail begins with "/"
if (tail.size() == 1) {
ret = TERMINAL_NNS_COMPONENT;
//System.out.println("terminal_nns : " + head);
} else if (head.isEmpty() || isAllEmpty(tail)) {
// resolve nns of head and continue with tail.getSuffix(1)
Name newTail = tail.getSuffix(1);
try {
Object obj = c_lookup_nns(head, cont);
//System.out.println("lookup_nns : " + head + "=" + obj);
if (obj != null)
cont.setContinue(obj, head, this, newTail);
else if (cont.isContinue()) {
cont.appendRemainingName(newTail);
// Name rname = cont.getRemainingName();
//System.out.println("cont.rname" + rname);
}
} catch (NamingException e) {
e.appendRemainingName(newTail);
throw e;
}
} else {
// head is being used as intermediate context
// resolve and set continuation to tail
try {
Object obj = c_resolveIntermediate_nns(head, cont);
//System.out.println("resInter2 : " + head + "=" + obj);
if (obj != null)
cont.setContinue(obj, head, this, tail);
else if (cont.isContinue()) {
checkAndAdjustRemainingName(cont.getRemainingName());
cont.appendRemainingName(tail);
}
} catch (NamingException e) {
checkAndAdjustRemainingName(e.getRemainingName());
e.appendRemainingName(tail);
throw e;
}
}
}
p.setStatus(ret);
return p;
}
// When c_resolveIntermediate_nns() or c_lookup_nns() sets up
// its continuation, to indicate "nns", it appends an empty
// component to the remaining name (e.g. "eng/"). If last
// component of remaining name is empty; delete empty component
// before appending tail so that composition of the names work
// correctly. For example, when merging "eng/" and "c.b.a", we want
// the result to be "eng/c.b.a" because the trailing slash in eng
// is extraneous. When merging "" and "c.b.a", we want the result
// to be "/c.b.a" and so must keep the trailing slash (empty name).
void checkAndAdjustRemainingName(Name rname) throws InvalidNameException {
int count;
if (rname != null && (count=rname.size()) > 1 &&
rname.get(count-1).equals("")) {
rname.remove(count-1);
}
}
// Returns true if n contains only empty components
protected boolean isAllEmpty(Name n) {
int count = n.size();
for (int i =0; i < count; i++ ) {
if (!n.get(i).equals("")) {
return false;
}
}
return true;
}
// ------ implementations of p_ Resolver and Context methods using
// ------ corresponding c_ and c_*_nns methods
/* implementation for Resolver method */
protected ResolveResult p_resolveToClass(Name name,
Class<?> contextType,
Continuation cont)
throws NamingException {
if (contextType.isInstance(this)) {
cont.setSuccess();
return (new ResolveResult(this, name));
}
ResolveResult ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
Object obj = p_lookup(name, cont);
if (!cont.isContinue() && contextType.isInstance(obj)) {
ret = new ResolveResult(obj, _EMPTY_NAME);
}
break;
case TERMINAL_COMPONENT:
cont.setSuccess(); // no contextType found; return null
break;
default:
/* USE_CONTINUATION */
/* pcont already set or exception thrown */
break;
}
return ret;
}
/* implementations of p_ Context methods */
protected Object p_lookup(Name name, Continuation cont) throws NamingException {
Object ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
ret = c_lookup_nns(res.getHead(), cont);
if (ret instanceof LinkRef) {
cont.setContinue(ret, res.getHead(), this);
ret = null;
}
break;
case TERMINAL_COMPONENT:
ret = c_lookup(res.getHead(), cont);
if (ret instanceof LinkRef) {
cont.setContinue(ret, res.getHead(), this);
ret = null;
}
break;
default:
/* USE_CONTINUATION */
/* pcont already set or exception thrown */
break;
}
return ret;
}
protected NamingEnumeration<NameClassPair> p_list(Name name, Continuation cont)
throws NamingException {
NamingEnumeration<NameClassPair> ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
if (debug > 0)
System.out.println("c_list_nns(" + res.getHead() + ")");
ret = c_list_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
if (debug > 0)
System.out.println("c_list(" + res.getHead() + ")");
ret = c_list(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
return ret;
}
protected NamingEnumeration<Binding> p_listBindings(Name name, Continuation cont) throws
NamingException {
NamingEnumeration<Binding> ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
ret = c_listBindings_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
ret = c_listBindings(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
return ret;
}
protected void p_bind(Name name, Object obj, Continuation cont) throws
NamingException {
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
c_bind_nns(res.getHead(), obj, cont);
break;
case TERMINAL_COMPONENT:
c_bind(res.getHead(), obj, cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
}
protected void p_rebind(Name name, Object obj, Continuation cont) throws
NamingException {
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
c_rebind_nns(res.getHead(), obj, cont);
break;
case TERMINAL_COMPONENT:
c_rebind(res.getHead(), obj, cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
}
protected void p_unbind(Name name, Continuation cont) throws
NamingException {
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
c_unbind_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
c_unbind(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
}
protected void p_destroySubcontext(Name name, Continuation cont) throws
NamingException {
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
c_destroySubcontext_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
c_destroySubcontext(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
}
protected Context p_createSubcontext(Name name, Continuation cont) throws
NamingException {
Context ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
ret = c_createSubcontext_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
ret = c_createSubcontext(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
return ret;
}
protected void p_rename(Name oldName, Name newName, Continuation cont) throws
NamingException {
HeadTail res = p_resolveIntermediate(oldName, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
c_rename_nns(res.getHead(), newName, cont);
break;
case TERMINAL_COMPONENT:
c_rename(res.getHead(), newName, cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
}
protected NameParser p_getNameParser(Name name, Continuation cont) throws
NamingException {
NameParser ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
ret = c_getNameParser_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
ret = c_getNameParser(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
return ret;
}
protected Object p_lookupLink(Name name, Continuation cont)
throws NamingException {
Object ret = null;
HeadTail res = p_resolveIntermediate(name, cont);
switch (res.getStatus()) {
case TERMINAL_NNS_COMPONENT:
ret = c_lookupLink_nns(res.getHead(), cont);
break;
case TERMINAL_COMPONENT:
ret = c_lookupLink(res.getHead(), cont);
break;
default:
/* USE_CONTINUATION */
/* cont already set or exception thrown */
break;
}
return ret;
}
}
/*
* How p_resolveIntermediate() should behave for various test cases
a.b/x {a.b, x}
c_resolveIntermediate_nns(a.b)
continue(x)
{x,}
terminal(x)
a.b/ {a.b, ""}
terminal_nns(a.b);
a.b//
{a.b, ("", "")}
c_lookup_nns(a.b)
continue({""})
{,""}
terminal_nns({})
/x {{}, {"", x}}
c_lookup_nns({})
continue(x)
{x,}
terminal(x)
//y {{}, {"", "", y}}
c_lookup_nns({})
continue({"", y})
{{}, {"", y}}
c_lookup_nns({})
continue(y)
{y,}
terminal(y)
a.b//y {a.b, {"", y}}
c_resolveIntermediate_nns(a.b)
continue({"", y})
{{}, {"",y}}
c_lookup_nns({});
continue(y)
{y,}
terminal(y);
*
*/
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