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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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package com.sun.jndi.toolkit.ctx;

import java.util.Hashtable;
import java.util.Enumeration;

import javax.naming.*;
import javax.naming.spi.Resolver;
import javax.naming.spi.ResolveResult;
import javax.naming.spi.NamingManager;

PartialCompositeContext implements Context operations on
composite names using implementations of the p_ interfaces
defined by its subclasses.
The main purpose provided by this class is that it deals with
partial resolutions and continuations, so that callers of the
Context operation don't have to.
Types of clients that will be direct subclasses of
PartialCompositeContext may be service providers that implement
one of the JNDI protocols, but which do not deal with
continuations.  Usually, service providers will be using
one of the subclasses of PartialCompositeContext.
Author:
Rosanna Lee/**
  * PartialCompositeContext implements Context operations on
  * composite names using implementations of the p_ interfaces
  * defined by its subclasses.
  *
  * The main purpose provided by this class is that it deals with
  * partial resolutions and continuations, so that callers of the
  * Context operation don't have to.
  *
  * Types of clients that will be direct subclasses of
  * PartialCompositeContext may be service providers that implement
  * one of the JNDI protocols, but which do not deal with
  * continuations.  Usually, service providers will be using
  * one of the subclasses of PartialCompositeContext.
  *
  * @author Rosanna Lee
  */


public abstract class PartialCompositeContext implements Context, Resolver {
    protected static final int _PARTIAL = 1;
    protected static final int _COMPONENT = 2;
    protected static final int _ATOMIC = 3;

    protected int _contextType = _PARTIAL;

    static final CompositeName _EMPTY_NAME = new CompositeName();
    static CompositeName _NNS_NAME;

    static {
        try {
            _NNS_NAME = new CompositeName("/");
        } catch (InvalidNameException e) {
            // Should never happen
        }
    }

    protected PartialCompositeContext() {
    }

// ------ Abstract methods whose implementations come from subclasses

    /* Equivalent to method in  Resolver interface */
    protected abstract ResolveResult p_resolveToClass(Name name,
        Class<?> contextType, Continuation cont) throws NamingException;

    /* Equivalent to methods in Context interface */
    protected abstract Object p_lookup(Name name, Continuation cont)
        throws NamingException;
    protected abstract Object p_lookupLink(Name name, Continuation cont)
        throws NamingException;
    protected abstract NamingEnumeration<NameClassPair> p_list(Name name,
        Continuation cont) throws NamingException;
    protected abstract NamingEnumeration<Binding> p_listBindings(Name name,
        Continuation cont) throws NamingException;
    protected abstract void p_bind(Name name, Object obj, Continuation cont)
        throws NamingException;
    protected abstract void p_rebind(Name name, Object obj, Continuation cont)
        throws NamingException;
    protected abstract void p_unbind(Name name, Continuation cont)
        throws NamingException;
    protected abstract void p_destroySubcontext(Name name, Continuation cont)
        throws NamingException;
    protected abstract Context p_createSubcontext(Name name, Continuation cont)
        throws NamingException;
    protected abstract void p_rename(Name oldname, Name newname,
                                     Continuation cont)
        throws NamingException;
    protected abstract NameParser p_getNameParser(Name name, Continuation cont)
        throws NamingException;

// ------ should be overridden by subclass;
// ------ not abstract only for backward compatibility

    
A cheap way of getting the environment.
Default implementation is NOT cheap because it simply calls
getEnvironment(), which most implementations clone before returning.
Subclass should ALWAYS override this with the cheapest possible way.
The toolkit knows to clone when necessary.
Returns:
The possibly null environment of the context./**
     * A cheap way of getting the environment.
     * Default implementation is NOT cheap because it simply calls
     * getEnvironment(), which most implementations clone before returning.
     * Subclass should ALWAYS override this with the cheapest possible way.
     * The toolkit knows to clone when necessary.
     * @return The possibly null environment of the context.
     */
    protected Hashtable<?,?> p_getEnvironment() throws NamingException {
        return getEnvironment();
    }


// ------ implementations of methods in Resolver and Context
// ------ using corresponding p_ methods provided by subclass

    /* implementations for method in Resolver interface using p_ method */

    public ResolveResult resolveToClass(String name,
                                        Class<? extends Context> contextType)
        throws NamingException
    {
        return resolveToClass(new CompositeName(name), contextType);
    }

    public ResolveResult resolveToClass(Name name,
                                        Class<? extends Context> contextType)
        throws NamingException
    {
        PartialCompositeContext ctx = this;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);
        ResolveResult answer;
        Name nm = name;

        try {
            answer = ctx.p_resolveToClass(nm, contextType, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_resolveToClass(nm, contextType, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            if (!(cctx instanceof Resolver)) {
                throw e;
            }
            answer = ((Resolver)cctx).resolveToClass(e.getRemainingName(),
                                                     contextType);
        }
        return answer;
    }

    /* implementations for methods in Context interface using p_ methods */

    public Object lookup(String name) throws NamingException {
        return lookup(new CompositeName(name));
    }

    public Object lookup(Name name) throws NamingException {
        PartialCompositeContext ctx = this;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);
        Object answer;
        Name nm = name;

        try {
            answer = ctx.p_lookup(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_lookup(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            answer = cctx.lookup(e.getRemainingName());
        }
        return answer;
    }

    public void bind(String name, Object newObj) throws NamingException {
        bind(new CompositeName(name), newObj);
    }

    public void bind(Name name, Object newObj) throws NamingException {
        PartialCompositeContext ctx = this;
        Name nm = name;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            ctx.p_bind(nm, newObj, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                ctx.p_bind(nm, newObj, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            cctx.bind(e.getRemainingName(), newObj);
        }
    }

    public void rebind(String name, Object newObj) throws NamingException {
        rebind(new CompositeName(name), newObj);
    }
    public void rebind(Name name, Object newObj) throws NamingException {
        PartialCompositeContext ctx = this;
        Name nm = name;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            ctx.p_rebind(nm, newObj, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                ctx.p_rebind(nm, newObj, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            cctx.rebind(e.getRemainingName(), newObj);
        }
    }

    public void unbind(String name) throws NamingException {
        unbind(new CompositeName(name));
    }
    public void unbind(Name name) throws NamingException {
        PartialCompositeContext ctx = this;
        Name nm = name;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            ctx.p_unbind(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                ctx.p_unbind(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            cctx.unbind(e.getRemainingName());
        }
    }

    public void rename(String oldName, String newName) throws NamingException {
        rename(new CompositeName(oldName), new CompositeName(newName));
    }
    public void rename(Name oldName, Name newName)
        throws NamingException
    {
        PartialCompositeContext ctx = this;
        Name nm = oldName;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(oldName, env);

        try {
            ctx.p_rename(nm, newName, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                ctx.p_rename(nm, newName, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            if (e.getRemainingNewName() != null) {
                // %%% e.getRemainingNewName() should never be null
                newName = e.getRemainingNewName();
            }
            cctx.rename(e.getRemainingName(), newName);
        }
    }

    public NamingEnumeration<NameClassPair> list(String name)
        throws NamingException
    {
        return list(new CompositeName(name));
    }

    public NamingEnumeration<NameClassPair> list(Name name)
        throws NamingException
    {
        PartialCompositeContext ctx = this;
        Name nm = name;
        NamingEnumeration<NameClassPair> answer;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            answer = ctx.p_list(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_list(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            answer = cctx.list(e.getRemainingName());
        }
        return answer;
    }

    public NamingEnumeration<Binding> listBindings(String name)
        throws NamingException
    {
        return listBindings(new CompositeName(name));
    }

    public NamingEnumeration<Binding> listBindings(Name name)
        throws NamingException
    {
        PartialCompositeContext ctx = this;
        Name nm = name;
        NamingEnumeration<Binding> answer;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            answer = ctx.p_listBindings(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_listBindings(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            answer = cctx.listBindings(e.getRemainingName());
        }
        return answer;
    }

    public void destroySubcontext(String name) throws NamingException {
        destroySubcontext(new CompositeName(name));
    }

    public void destroySubcontext(Name name) throws NamingException {
        PartialCompositeContext ctx = this;
        Name nm = name;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            ctx.p_destroySubcontext(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                ctx.p_destroySubcontext(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            cctx.destroySubcontext(e.getRemainingName());
        }
    }

    public Context createSubcontext(String name) throws NamingException {
        return createSubcontext(new CompositeName(name));
    }

    public Context createSubcontext(Name name) throws NamingException {
        PartialCompositeContext ctx = this;
        Name nm = name;
        Context answer;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            answer = ctx.p_createSubcontext(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_createSubcontext(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            answer = cctx.createSubcontext(e.getRemainingName());
        }
        return answer;
    }

    public Object lookupLink(String name) throws NamingException {
        return lookupLink(new CompositeName(name));
    }

    public Object lookupLink(Name name) throws NamingException {
        PartialCompositeContext ctx = this;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);
        Object answer;
        Name nm = name;

        try {
            answer = ctx.p_lookupLink(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_lookupLink(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            answer = cctx.lookupLink(e.getRemainingName());
        }
        return answer;
    }

    public NameParser getNameParser(String name) throws NamingException {
        return getNameParser(new CompositeName(name));
    }

    public NameParser getNameParser(Name name) throws NamingException {
        PartialCompositeContext ctx = this;
        Name nm = name;
        NameParser answer;
        Hashtable<?,?> env = p_getEnvironment();
        Continuation cont = new Continuation(name, env);

        try {
            answer = ctx.p_getNameParser(nm, cont);
            while (cont.isContinue()) {
                nm = cont.getRemainingName();
                ctx = getPCContext(cont);
                answer = ctx.p_getNameParser(nm, cont);
            }
        } catch (CannotProceedException e) {
            Context cctx = NamingManager.getContinuationContext(e);
            answer = cctx.getNameParser(e.getRemainingName());
        }
        return answer;
    }

    public String composeName(String name, String prefix)
            throws NamingException {
        Name fullName = composeName(new CompositeName(name),
                                    new CompositeName(prefix));
        return fullName.toString();
    }

    
This default implementation simply concatenates the two names.
There's one twist when the "java.naming.provider.compose.elideEmpty"
environment setting is set to "true":  if each name contains a
nonempty component, and if 'prefix' ends with an empty component or
'name' starts with one, then one empty component is dropped.
For example:

                           elideEmpty=false     elideEmpty=true
{"a"} + {"b"}          =>  {"a", "b"}           {"a", "b"}
{"a"} + {""}           =>  {"a", ""}            {"a", ""}
{"a"} + {"", "b"}      =>  {"a", "", "b"}       {"a", "b"}
{"a", ""} + {"b", ""}  =>  {"a", "", "b", ""}   {"a", "b", ""}
{"a", ""} + {"", "b"}  =>  {"a", "", "", "b"}   {"a", "", "b"}

/**
     * This default implementation simply concatenates the two names.
     * There's one twist when the "java.naming.provider.compose.elideEmpty"
     * environment setting is set to "true":  if each name contains a
     * nonempty component, and if 'prefix' ends with an empty component or
     * 'name' starts with one, then one empty component is dropped.
     * For example:
     * <pre>{@code
     *                            elideEmpty=false     elideEmpty=true
     * {"a"} + {"b"}          =>  {"a", "b"}           {"a", "b"}
     * {"a"} + {""}           =>  {"a", ""}            {"a", ""}
     * {"a"} + {"", "b"}      =>  {"a", "", "b"}       {"a", "b"}
     * {"a", ""} + {"b", ""}  =>  {"a", "", "b", ""}   {"a", "b", ""}
     * {"a", ""} + {"", "b"}  =>  {"a", "", "", "b"}   {"a", "", "b"}
     * }</pre>
     */
    public Name composeName(Name name, Name prefix) throws NamingException {
        Name res = (Name)prefix.clone();
        if (name == null) {
            return res;
        }
        res.addAll(name);

        String elide = (String)
            p_getEnvironment().get("java.naming.provider.compose.elideEmpty");
        if (elide == null || !elide.equalsIgnoreCase("true")) {
            return res;
        }

        int len = prefix.size();

        if (!allEmpty(prefix) && !allEmpty(name)) {
            if (res.get(len - 1).equals("")) {
                res.remove(len - 1);
            } else if (res.get(len).equals("")) {
                res.remove(len);
            }
        }
        return res;
    }


// ------ internal methods used by PartialCompositeContext

    
Tests whether a name contains a nonempty component.
/**
     * Tests whether a name contains a nonempty component.
     */
    protected static boolean allEmpty(Name name) {
        Enumeration<String> enum_ = name.getAll();
        while (enum_.hasMoreElements()) {
            if (!enum_.nextElement().isEmpty()) {
                return false;
            }
        }
        return true;
    }

    
Retrieves a PartialCompositeContext for the resolved object in
cont.  Throws CannotProceedException if not successful.
/**
     * Retrieves a PartialCompositeContext for the resolved object in
     * cont.  Throws CannotProceedException if not successful.
     */
    protected static PartialCompositeContext getPCContext(Continuation cont)
            throws NamingException {

        Object obj = cont.getResolvedObj();
        PartialCompositeContext pctx = null;

        if (obj instanceof PartialCompositeContext) {
            // Just cast if octx already is PartialCompositeContext
            // %%% ignoring environment for now
            return (PartialCompositeContext)obj;
        } else {
            throw cont.fillInException(new CannotProceedException());
        }
    }
};