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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.
*
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package com.sun.jndi.dns;
import java.util.Hashtable;
/**
* A NameNode represents a node in the DNS namespace. Each node
* has a label, which is its name relative to its parent (so the
* node at Sun.COM has label "Sun"). Each node has a hashtable of
* children indexed by their labels converted to lower-case.
*
* <p> A node may be addressed from another by giving a DnsName
* consisting of the sequence of labels from one node to the other.
*
* <p> Each node also has an {@code isZoneCut} flag, used to indicate
* if the node is a zone cut. A zone cut is a node with an NS record
* that is contained in one zone, but that actually belongs to a child zone.
*
* <p> All access is unsynchronized.
*
* @author Scott Seligman
*/
class NameNode {
private String label; // name of this node relative to its
// parent, or null for root of a tree
private Hashtable<String,NameNode> children = null; // child nodes
private boolean isZoneCut = false; // true if this node is a zone cut
private int depth = 0; // depth in tree (0 for root)
NameNode(String label) {
this.label = label;
}
/*
* Returns a newly-allocated NameNode. Used to allocate new nodes
* in a tree. Should be overridden in a subclass to return an object
* of the subclass's type.
*/
protected NameNode newNameNode(String label) {
return new NameNode(label);
}
/*
* Returns the name of this node relative to its parent, or null for
* the root of a tree.
*/
String getLabel() {
return label;
}
/*
* Returns the depth of this node in the tree. The depth of the root
* is 0.
*/
int depth() {
return depth;
}
boolean isZoneCut() {
return isZoneCut;
}
void setZoneCut(boolean isZoneCut) {
this.isZoneCut = isZoneCut;
}
/*
* Returns the children of this node, or null if there are none.
* The caller must not modify the Hashtable returned.
*/
Hashtable<String,NameNode> getChildren() {
return children;
}
/*
* Returns the child node given the hash key (the down-cased label)
* for its name relative to this node, or null if there is no such
* child.
*/
NameNode get(String key) {
return (children != null)
? children.get(key)
: null;
}
/*
* Returns the node at the end of a path, or null if the
* node does not exist.
* The path is specified by the labels of {@code name}, beginning
* at index idx.
*/
NameNode get(DnsName name, int idx) {
NameNode node = this;
for (int i = idx; i < name.size() && node != null; i++) {
node = node.get(name.getKey(i));
}
return node;
}
/*
* Returns the node at the end of a path, creating it and any
* intermediate nodes as needed.
* The path is specified by the labels of {@code name}, beginning
* at index idx.
*/
NameNode add(DnsName name, int idx) {
NameNode node = this;
for (int i = idx; i < name.size(); i++) {
String label = name.get(i);
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