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/*
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* Copyright (c) 2000, 2002, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package com.sun.jndi.dns;
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import java.util.Hashtable;
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/**
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* A NameNode represents a node in the DNS namespace. Each node
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* has a label, which is its name relative to its parent (so the
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* node at Sun.COM has label "Sun"). Each node has a hashtable of
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* children indexed by their labels converted to lower-case.
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*
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* <p> A node may be addressed from another by giving a DnsName
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* consisting of the sequence of labels from one node to the other.
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*
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* <p> Each node also has an <tt>isZoneCut</tt> flag, used to indicate
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* if the node is a zone cut. A zone cut is a node with an NS record
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* that is contained in one zone, but that actually belongs to a child zone.
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*
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* <p> All access is unsynchronized.
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*
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* @author Scott Seligman
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*/
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class NameNode {
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private String label; // name of this node relative to its
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// parent, or null for root of a tree
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private Hashtable children = null; // child nodes
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private boolean isZoneCut = false; // true if this node is a zone cut
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private int depth = 0; // depth in tree (0 for root)
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NameNode(String label) {
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this.label = label;
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}
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/*
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* Returns a newly-allocated NameNode. Used to allocate new nodes
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* in a tree. Should be overridden in a subclass to return an object
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* of the subclass's type.
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*/
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protected NameNode newNameNode(String label) {
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return new NameNode(label);
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}
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/*
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* Returns the name of this node relative to its parent, or null for
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* the root of a tree.
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*/
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String getLabel() {
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return label;
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}
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/*
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* Returns the depth of this node in the tree. The depth of the root
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* is 0.
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*/
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int depth() {
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return depth;
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}
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boolean isZoneCut() {
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return isZoneCut;
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}
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void setZoneCut(boolean isZoneCut) {
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this.isZoneCut = isZoneCut;
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}
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/*
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* Returns the children of this node, or null if there are none.
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* The caller must not modify the Hashtable returned.
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*/
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Hashtable getChildren() {
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return children;
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}
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/*
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* Returns the child node given the hash key (the down-cased label)
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* for its name relative to this node, or null if there is no such
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* child.
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*/
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NameNode get(String key) {
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return (children != null)
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? (NameNode) children.get(key)
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: null;
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}
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/*
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* Returns the node at the end of a path, or null if the
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* node does not exist.
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* The path is specified by the labels of <tt>name</tt>, beginning
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* at index idx.
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*/
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NameNode get(DnsName name, int idx) {
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NameNode node = this;
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for (int i = idx; i < name.size() && node != null; i++) {
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node = node.get(name.getKey(i));
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}
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return node;
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}
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/*
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* Returns the node at the end of a path, creating it and any
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* intermediate nodes as needed.
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* The path is specified by the labels of <tt>name</tt>, beginning
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* at index idx.
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*/
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NameNode add(DnsName name, int idx) {
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NameNode node = this;
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for (int i = idx; i < name.size(); i++) {
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String label = name.get(i);
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String key = name.getKey(i);
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NameNode child = null;
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if (node.children == null) {
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node.children = new Hashtable();
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} else {
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child = (NameNode) node.children.get(key);
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}
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if (child == null) {
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child = newNameNode(label);
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child.depth = node.depth + 1;
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node.children.put(key, child);
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}
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node = child;
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}
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return node;
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}
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}
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