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 * 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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package com.sun.jndi.toolkit.dir;

import javax.naming.*;

import javax.naming.directory.SearchControls;

import java.util.*;

/**

  * A class for recursively enumerating the contents of a Context;

  *

  * @author Jon Ruiz

  */

public class ContextEnumerator implements NamingEnumeration<Binding> {

    private static boolean debug = false;

    private NamingEnumeration<Binding> children = null;

    private Binding currentChild = null;

    private boolean currentReturned = false;

    private Context root;

    private ContextEnumerator currentChildEnum = null;

    private boolean currentChildExpanded = false;

    private boolean rootProcessed = false;

    private int scope = SearchControls.SUBTREE_SCOPE;

    private String contextName = "";

    public ContextEnumerator(Context context) throws NamingException {

        this(context, SearchControls.SUBTREE_SCOPE);

    }

    public ContextEnumerator(Context context, int scope)

        throws NamingException {

            // return this object except when searching single-level

        this(context, scope, "", scope != SearchControls.ONELEVEL_SCOPE);

   }

    protected ContextEnumerator(Context context, int scope, String contextName,

                             boolean returnSelf)

        throws NamingException {

        if(context == null) {

            throw new IllegalArgumentException("null context passed");

        }

        root = context;

        // No need to list children if we're only searching object

        if (scope != SearchControls.OBJECT_SCOPE) {

            children = getImmediateChildren(context);

        }

        this.scope = scope;

        this.contextName = contextName;

        // pretend root is processed, if we're not supposed to return ourself

        rootProcessed = !returnSelf;

        prepNextChild();

    }

    // Subclass should override if it wants to avoid calling obj factory

    protected NamingEnumeration<Binding> getImmediateChildren(Context ctx)

        throws NamingException {

            return ctx.listBindings("");

    }

    // Subclass should override so that instance is of same type as subclass

    protected ContextEnumerator newEnumerator(Context ctx, int scope,

        String contextName, boolean returnSelf) throws NamingException {

            return new ContextEnumerator(ctx, scope, contextName, returnSelf);

    }

    public boolean hasMore() throws NamingException {

        return !rootProcessed ||

            (scope != SearchControls.OBJECT_SCOPE && hasMoreDescendants());

    }

    public boolean hasMoreElements() {

        try {

            return hasMore();

        } catch (NamingException e) {

            return false;

        }

    }

    public Binding nextElement() {

        try {

            return next();

        } catch (NamingException e) {

            throw new NoSuchElementException(e.toString());

        }

    }

    public Binding next() throws NamingException {

        if (!rootProcessed) {

            rootProcessed = true;

            return new Binding("", root.getClass().getName(),

                               root, true);

        }

        if (scope != SearchControls.OBJECT_SCOPE && hasMoreDescendants()) {

            return getNextDescendant();

        }

        throw new NoSuchElementException();

    }

    public void close() throws NamingException {

        root = null;

    }

    private boolean hasMoreChildren() throws NamingException {

        return children != null && children.hasMore();

    }

    private Binding getNextChild() throws NamingException {

        Binding oldBinding = children.next();

        Binding newBinding = null;

        // if the name is relative, we need to add it to the name of this

        // context to keep it relative w.r.t. the root context we are

        // enumerating

        if(oldBinding.isRelative() && !contextName.equals("")) {

            NameParser parser = root.getNameParser("");

            Name newName = parser.parse(contextName);

            newName.add(oldBinding.getName());

            if(debug) {

                System.out.println("ContextEnumerator: adding " + newName);

            }

            newBinding = new Binding(newName.toString(),

                                     oldBinding.getClassName(),

                                     oldBinding.getObject(),

                                     oldBinding.isRelative());

        } else {

            if(debug) {

                System.out.println("ContextEnumerator: using old binding");

            }

            newBinding = oldBinding;

        }

        return newBinding;

    }

    private boolean hasMoreDescendants() throws NamingException {

        // if the current child is expanded, see if it has more elements

        if (!currentReturned) {

            if(debug) {System.out.println("hasMoreDescendants returning " +

                                          (currentChild != null) ); }

            return currentChild != null;

        } else if (currentChildExpanded && currentChildEnum.hasMore()) {

            if(debug) {System.out.println("hasMoreDescendants returning " +

                "true");}

            return true;

        } else {

            if(debug) {System.out.println("hasMoreDescendants returning " +

                "hasMoreChildren");}

            return hasMoreChildren();

        }

    }

    private Binding getNextDescendant() throws NamingException {

        if (!currentReturned) {

            // returning parent

            currentReturned = true;

            return currentChild;

        } else if (currentChildExpanded && currentChildEnum.hasMore()) {

            // if the current child is expanded, use it's enumerator

            return currentChildEnum.next();

        } else {

            // Ready to go onto next child

            prepNextChild();

            return getNextDescendant();

        }

    }

    private void prepNextChild() throws NamingException {

        if(hasMoreChildren()) {

            try {

                currentChild = getNextChild();

                currentReturned = false;

            } catch (NamingException e){

                if (debug) System.out.println(e);

                if (debug) e.printStackTrace();

            }

        } else {

            currentChild = null;

            return;

        }

        if(scope == SearchControls.SUBTREE_SCOPE &&

           currentChild.getObject() instanceof Context) {

            currentChildEnum = newEnumerator(

                                          (Context)(currentChild.getObject()),

                                          scope, currentChild.getName(),

                                          false);

            currentChildExpanded = true;

            if(debug) {System.out.println("prepNextChild: expanded");}

        } else {

            currentChildExpanded = false;

            currentChildEnum = null;

            if(debug) {System.out.println("prepNextChild: normal");}

        }

    }

}