src/org/xbill/DNS/Zone.java - platform/external/smack - Git at Google

 // Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

 package org.xbill.DNS;

 import java.io.*;
 import java.util.*;

 /**
  * A DNS Zone.  This encapsulates all data related to a Zone, and provides
  * convenient lookup methods.
  *
  * @author Brian Wellington
  */

 public class Zone implements Serializable {

 private static final long serialVersionUID = -9220510891189510942L;

 /** A primary zone */
 public static final int PRIMARY = 1;

 /** A secondary zone */
 public static final int SECONDARY = 2;

 private Map data;
 private Name origin;
 private Object originNode;
 private int dclass = DClass.IN;
 private RRset NS;
 private SOARecord SOA;
 private boolean hasWild;

 class ZoneIterator implements Iterator {
 	private Iterator zentries;
 	private RRset [] current;
 	private int count;
 	private boolean wantLastSOA;

 	ZoneIterator(boolean axfr) {
 		synchronized (Zone.this) {
 			zentries = data.entrySet().iterator();
 		}
 		wantLastSOA = axfr;
 		RRset [] sets = allRRsets(originNode);
 		current = new RRset[sets.length];
 		for (int i = 0, j = 2; i < sets.length; i++) {
 			int type = sets[i].getType();
 			if (type == Type.SOA)
 				current[0] = sets[i];
 			else if (type == Type.NS)
 				current[1] = sets[i];
 			else
 				current[j++] = sets[i];
 		}
 	}

 	public boolean
 	hasNext() {
 		return (current != null || wantLastSOA);
 	}

 	public Object
 	next() {
 		if (!hasNext()) {
 			throw new NoSuchElementException();
 		}
 		if (current == null) {
 			wantLastSOA = false;
 			return oneRRset(originNode, Type.SOA);
 		}
 		Object set = current[count++];
 		if (count == current.length) {
 			current = null;
 			while (zentries.hasNext()) {
 				Map.Entry entry = (Map.Entry) zentries.next();
 				if (entry.getKey().equals(origin))
 					continue;
 				RRset [] sets = allRRsets(entry.getValue());
 				if (sets.length == 0)
 					continue;
 				current = sets;
 				count = 0;
 				break;
 			}
 		}
 		return set;
 	}

 	public void
 	remove() {
 		throw new UnsupportedOperationException();
 	}
 }

 private void
 validate() throws IOException {
 	originNode = exactName(origin);
 	if (originNode == null)
 		throw new IOException(origin + ": no data specified");

 	RRset rrset = oneRRset(originNode, Type.SOA);
 	if (rrset == null || rrset.size() != 1)
 		throw new IOException(origin +
 				      ": exactly 1 SOA must be specified");
 	Iterator it = rrset.rrs();
 	SOA = (SOARecord) it.next();

 	NS = oneRRset(originNode, Type.NS);
 	if (NS == null)
 		throw new IOException(origin + ": no NS set specified");
 }

 private final void
 maybeAddRecord(Record record) throws IOException {
 	int rtype = record.getType();
 	Name name = record.getName();

 	if (rtype == Type.SOA && !name.equals(origin)) {
 		throw new IOException("SOA owner " + name +
 				      " does not match zone origin " +
 				      origin);
 	}
 	if (name.subdomain(origin))
 		addRecord(record);
 }

 /**
  * Creates a Zone from the records in the specified master file.
  * @param zone The name of the zone.
  * @param file The master file to read from.
  * @see Master
  */
 public
 Zone(Name zone, String file) throws IOException {
 	data = new TreeMap();

 	if (zone == null)
 		throw new IllegalArgumentException("no zone name specified");
 	Master m = new Master(file, zone);
 	Record record;

 	origin = zone;
 	while ((record = m.nextRecord()) != null)
 		maybeAddRecord(record);
 	validate();
 }

 /**
  * Creates a Zone from an array of records.
  * @param zone The name of the zone.
  * @param records The records to add to the zone.
  * @see Master
  */
 public
 Zone(Name zone, Record [] records) throws IOException {
 	data = new TreeMap();

 	if (zone == null)
 		throw new IllegalArgumentException("no zone name specified");
 	origin = zone;
 	for (int i = 0; i < records.length; i++)
 		maybeAddRecord(records[i]);
 	validate();
 }

 private void
 fromXFR(ZoneTransferIn xfrin) throws IOException, ZoneTransferException {
 	data = new TreeMap();

 	origin = xfrin.getName();
 	List records = xfrin.run();
 	for (Iterator it = records.iterator(); it.hasNext(); ) {
 		Record record = (Record) it.next();
 		maybeAddRecord(record);
 	}
 	if (!xfrin.isAXFR())
 		throw new IllegalArgumentException("zones can only be " +
 						   "created from AXFRs");
 	validate();
 }

 /**
  * Creates a Zone by doing the specified zone transfer.
  * @param xfrin The incoming zone transfer to execute.
  * @see ZoneTransferIn
  */
 public
 Zone(ZoneTransferIn xfrin) throws IOException, ZoneTransferException {
 	fromXFR(xfrin);
 }

 /**
  * Creates a Zone by performing a zone transfer to the specified host.
  * @see ZoneTransferIn
  */
 public
 Zone(Name zone, int dclass, String remote)
 throws IOException, ZoneTransferException
 {
 	ZoneTransferIn xfrin = ZoneTransferIn.newAXFR(zone, remote, null);
 	xfrin.setDClass(dclass);
 	fromXFR(xfrin);
 }

 /** Returns the Zone's origin */
 public Name
 getOrigin() {
 	return origin;
 }

 /** Returns the Zone origin's NS records */
 public RRset
 getNS() {
 	return NS;
 }

 /** Returns the Zone's SOA record */
 public SOARecord
 getSOA() {
 	return SOA;
 }

 /** Returns the Zone's class */
 public int
 getDClass() {
 	return dclass;
 }

 private synchronized Object
 exactName(Name name) {
 	return data.get(name);
 }

 private synchronized RRset []
 allRRsets(Object types) {
 	if (types instanceof List) {
 		List typelist = (List) types;
 		return (RRset []) typelist.toArray(new RRset[typelist.size()]);
 	} else {
 		RRset set = (RRset) types;
 		return new RRset [] {set};
 	}
 }

 private synchronized RRset
 oneRRset(Object types, int type) {
 	if (type == Type.ANY)
 		throw new IllegalArgumentException("oneRRset(ANY)");
 	if (types instanceof List) {
 		List list = (List) types;
 		for (int i = 0; i < list.size(); i++) {
 			RRset set = (RRset) list.get(i);
 			if (set.getType() == type)
 				return set;
 		}
 	} else {
 		RRset set = (RRset) types;
 		if (set.getType() == type)
 			return set;
 	}
 	return null;
 }

 private synchronized RRset
 findRRset(Name name, int type) {
 	Object types = exactName(name);
 	if (types == null)
 		return null;
 	return oneRRset(types, type);
 }

 private synchronized void
 addRRset(Name name, RRset rrset) {
 	if (!hasWild && name.isWild())
 		hasWild = true;
 	Object types = data.get(name);
 	if (types == null) {
 		data.put(name, rrset);
 		return;
 	}
 	int rtype = rrset.getType();
 	if (types instanceof List) {
 		List list = (List) types;
 		for (int i = 0; i < list.size(); i++) {
 			RRset set = (RRset) list.get(i);
 			if (set.getType() == rtype) {
 				list.set(i, rrset);
 				return;
 			}
 		}
 		list.add(rrset);
 	} else {
 		RRset set = (RRset) types;
 		if (set.getType() == rtype)
 			data.put(name, rrset);
 		else {
 			LinkedList list = new LinkedList();
 			list.add(set);
 			list.add(rrset);
 			data.put(name, list);
 		}
 	}
 }

 private synchronized void
 removeRRset(Name name, int type) {
 	Object types = data.get(name);
 	if (types == null) {
 		return;
 	}
 	if (types instanceof List) {
 		List list = (List) types;
 		for (int i = 0; i < list.size(); i++) {
 			RRset set = (RRset) list.get(i);
 			if (set.getType() == type) {
 				list.remove(i);
 				if (list.size() == 0)
 					data.remove(name);
 				return;
 			}
 		}
 	} else {
 		RRset set = (RRset) types;
 		if (set.getType() != type)
 			return;
 		data.remove(name);
 	}
 }

 private synchronized SetResponse
 lookup(Name name, int type) {
 	int labels;
 	int olabels;
 	int tlabels;
 	RRset rrset;
 	Name tname;
 	Object types;
 	SetResponse sr;

 	if (!name.subdomain(origin))
 		return SetResponse.ofType(SetResponse.NXDOMAIN);

 	labels = name.labels();
 	olabels = origin.labels();

 	for (tlabels = olabels; tlabels <= labels; tlabels++) {
 		boolean isOrigin = (tlabels == olabels);
 		boolean isExact = (tlabels == labels);

 		if (isOrigin)
 			tname = origin;
 		else if (isExact)
 			tname = name;
 		else
 			tname = new Name(name, labels - tlabels);

 		types = exactName(tname);
 		if (types == null)
 			continue;

 		/* If this is a delegation, return that. */
 		if (!isOrigin) {
 			RRset ns = oneRRset(types, Type.NS);
 			if (ns != null)
 				return new SetResponse(SetResponse.DELEGATION,
 						       ns);
 		}

 		/* If this is an ANY lookup, return everything. */
 		if (isExact && type == Type.ANY) {
 			sr = new SetResponse(SetResponse.SUCCESSFUL);
 			RRset [] sets = allRRsets(types);
 			for (int i = 0; i < sets.length; i++)
 				sr.addRRset(sets[i]);
 			return sr;
 		}

 		/*
 		 * If this is the name, look for the actual type or a CNAME.
 		 * Otherwise, look for a DNAME.
 		 */
 		if (isExact) {
 			rrset = oneRRset(types, type);
 			if (rrset != null) {
 				sr = new SetResponse(SetResponse.SUCCESSFUL);
 				sr.addRRset(rrset);
 				return sr;
 			}
 			rrset = oneRRset(types, Type.CNAME);
 			if (rrset != null)
 				return new SetResponse(SetResponse.CNAME,
 						       rrset);
 		} else {
 			rrset = oneRRset(types, Type.DNAME);
 			if (rrset != null)
 				return new SetResponse(SetResponse.DNAME,
 						       rrset);
 		}

 		/* We found the name, but not the type. */
 		if (isExact)
 			return SetResponse.ofType(SetResponse.NXRRSET);
 	}

 	if (hasWild) {
 		for (int i = 0; i < labels - olabels; i++) {
 			tname = name.wild(i + 1);

 			types = exactName(tname);
 			if (types == null)
 				continue;

 			rrset = oneRRset(types, type);
 			if (rrset != null) {
 				sr = new SetResponse(SetResponse.SUCCESSFUL);
 				sr.addRRset(rrset);
 				return sr;
 			}
 		}
 	}

 	return SetResponse.ofType(SetResponse.NXDOMAIN);
 }

 /**
  * Looks up Records in the Zone.  This follows CNAMEs and wildcards.
  * @param name The name to look up
  * @param type The type to look up
  * @return A SetResponse object
  * @see SetResponse
  */
 public SetResponse
 findRecords(Name name, int type) {
 	return lookup(name, type);
 }

 /**
  * Looks up Records in the zone, finding exact matches only.
  * @param name The name to look up
  * @param type The type to look up
  * @return The matching RRset
  * @see RRset
  */
 public RRset
 findExactMatch(Name name, int type) {
 	Object types = exactName(name);
 	if (types == null)
 		return null;
 	return oneRRset(types, type);
 }

 /**
  * Adds an RRset to the Zone
  * @param rrset The RRset to be added
  * @see RRset
  */
 public void
 addRRset(RRset rrset) {
 	Name name = rrset.getName();
 	addRRset(name, rrset);
 }

 /**
  * Adds a Record to the Zone
  * @param r The record to be added
  * @see Record
  */
 public void
 addRecord(Record r) {
 	Name name = r.getName();
 	int rtype = r.getRRsetType();
 	synchronized (this) {
 		RRset rrset = findRRset(name, rtype);
 		if (rrset == null) {
 			rrset = new RRset(r);
 			addRRset(name, rrset);
 		} else {
 			rrset.addRR(r);
 		}
 	}
 }

 /**
  * Removes a record from the Zone
  * @param r The record to be removed
  * @see Record
  */
 public void
 removeRecord(Record r) {
 	Name name = r.getName();
 	int rtype = r.getRRsetType();
 	synchronized (this) {
 		RRset rrset = findRRset(name, rtype);
 		if (rrset == null)
 			return;
 		if (rrset.size() == 1 && rrset.first().equals(r))
 			removeRRset(name, rtype);
 		else
 			rrset.deleteRR(r);
 	}
 }

 /**
  * Returns an Iterator over the RRsets in the zone.
  */
 public Iterator
 iterator() {
 	return new ZoneIterator(false);
 }

 /**
  * Returns an Iterator over the RRsets in the zone that can be used to
  * construct an AXFR response.  This is identical to {@link #iterator} except
  * that the SOA is returned at the end as well as the beginning.
  */
 public Iterator
 AXFR() {
 	return new ZoneIterator(true);
 }

 private void
 nodeToString(StringBuffer sb, Object node) {
 	RRset [] sets = allRRsets(node);
 	for (int i = 0; i < sets.length; i++) {
 		RRset rrset = sets[i];
 		Iterator it = rrset.rrs();
 		while (it.hasNext())
 			sb.append(it.next() + "\n");
 		it = rrset.sigs();
 		while (it.hasNext())
 			sb.append(it.next() + "\n");
 	}
 }

 /**
  * Returns the contents of the Zone in master file format.
  */
 public synchronized String
 toMasterFile() {
 	Iterator zentries = data.entrySet().iterator();
 	StringBuffer sb = new StringBuffer();
 	nodeToString(sb, originNode);
 	while (zentries.hasNext()) {
 		Map.Entry entry = (Map.Entry) zentries.next();
 		if (!origin.equals(entry.getKey()))
 			nodeToString(sb, entry.getValue());
 	}
 	return sb.toString();
 }

 /**
  * Returns the contents of the Zone as a string (in master file format).
  */
 public String
 toString() {
 	return toMasterFile();
 }

 }
	// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

	package org.xbill.DNS;

	import java.io.*;
	import java.util.*;

	/**
	* A DNS Zone. This encapsulates all data related to a Zone, and provides
	* convenient lookup methods.
	*
	* @author Brian Wellington
	*/

	public class Zone implements Serializable {

	private static final long serialVersionUID = -9220510891189510942L;

	/** A primary zone */
	public static final int PRIMARY = 1;

	/** A secondary zone */
	public static final int SECONDARY = 2;

	private Map data;
	private Name origin;
	private Object originNode;
	private int dclass = DClass.IN;
	private RRset NS;
	private SOARecord SOA;
	private boolean hasWild;

	class ZoneIterator implements Iterator {
	private Iterator zentries;
	private RRset [] current;
	private int count;
	private boolean wantLastSOA;

	ZoneIterator(boolean axfr) {
	synchronized (Zone.this) {
	zentries = data.entrySet().iterator();
	}
	wantLastSOA = axfr;
	RRset [] sets = allRRsets(originNode);
	current = new RRset[sets.length];
	for (int i = 0, j = 2; i < sets.length; i++) {
	int type = sets[i].getType();
	if (type == Type.SOA)
	current[0] = sets[i];
	else if (type == Type.NS)
	current[1] = sets[i];
	else
	current[j++] = sets[i];
	}
	}

	public boolean
	hasNext() {
	return (current != null \|\| wantLastSOA);
	}

	public Object
	next() {
	if (!hasNext()) {
	throw new NoSuchElementException();
	}
	if (current == null) {
	wantLastSOA = false;
	return oneRRset(originNode, Type.SOA);
	}
	Object set = current[count++];
	if (count == current.length) {
	current = null;
	while (zentries.hasNext()) {
	Map.Entry entry = (Map.Entry) zentries.next();
	if (entry.getKey().equals(origin))
	continue;
	RRset [] sets = allRRsets(entry.getValue());
	if (sets.length == 0)
	continue;
	current = sets;
	count = 0;
	break;
	}
	}
	return set;
	}

	public void
	remove() {
	throw new UnsupportedOperationException();
	}
	}

	private void
	validate() throws IOException {
	originNode = exactName(origin);
	if (originNode == null)
	throw new IOException(origin + ": no data specified");

	RRset rrset = oneRRset(originNode, Type.SOA);
	if (rrset == null \|\| rrset.size() != 1)
	throw new IOException(origin +
	": exactly 1 SOA must be specified");
	Iterator it = rrset.rrs();
	SOA = (SOARecord) it.next();

	NS = oneRRset(originNode, Type.NS);
	if (NS == null)
	throw new IOException(origin + ": no NS set specified");
	}

	private final void
	maybeAddRecord(Record record) throws IOException {
	int rtype = record.getType();
	Name name = record.getName();

	if (rtype == Type.SOA && !name.equals(origin)) {
	throw new IOException("SOA owner " + name +
	" does not match zone origin " +
	origin);
	}
	if (name.subdomain(origin))
	addRecord(record);
	}

	/**
	* Creates a Zone from the records in the specified master file.
	* @param zone The name of the zone.
	* @param file The master file to read from.
	* @see Master
	*/
	public
	Zone(Name zone, String file) throws IOException {
	data = new TreeMap();

	if (zone == null)
	throw new IllegalArgumentException("no zone name specified");
	Master m = new Master(file, zone);
	Record record;

	origin = zone;
	while ((record = m.nextRecord()) != null)
	maybeAddRecord(record);
	validate();
	}

	/**
	* Creates a Zone from an array of records.
	* @param zone The name of the zone.
	* @param records The records to add to the zone.
	* @see Master
	*/
	public
	Zone(Name zone, Record [] records) throws IOException {
	data = new TreeMap();

	if (zone == null)
	throw new IllegalArgumentException("no zone name specified");
	origin = zone;
	for (int i = 0; i < records.length; i++)
	maybeAddRecord(records[i]);
	validate();
	}

	private void
	fromXFR(ZoneTransferIn xfrin) throws IOException, ZoneTransferException {
	data = new TreeMap();

	origin = xfrin.getName();
	List records = xfrin.run();
	for (Iterator it = records.iterator(); it.hasNext(); ) {
	Record record = (Record) it.next();
	maybeAddRecord(record);
	}
	if (!xfrin.isAXFR())
	throw new IllegalArgumentException("zones can only be " +
	"created from AXFRs");
	validate();
	}

	/**
	* Creates a Zone by doing the specified zone transfer.
	* @param xfrin The incoming zone transfer to execute.
	* @see ZoneTransferIn
	*/
	public
	Zone(ZoneTransferIn xfrin) throws IOException, ZoneTransferException {
	fromXFR(xfrin);
	}

	/**
	* Creates a Zone by performing a zone transfer to the specified host.
	* @see ZoneTransferIn
	*/
	public
	Zone(Name zone, int dclass, String remote)
	throws IOException, ZoneTransferException
	{
	ZoneTransferIn xfrin = ZoneTransferIn.newAXFR(zone, remote, null);
	xfrin.setDClass(dclass);
	fromXFR(xfrin);
	}

	/** Returns the Zone's origin */
	public Name
	getOrigin() {
	return origin;
	}

	/** Returns the Zone origin's NS records */
	public RRset
	getNS() {
	return NS;
	}

	/** Returns the Zone's SOA record */
	public SOARecord
	getSOA() {
	return SOA;
	}

	/** Returns the Zone's class */
	public int
	getDClass() {
	return dclass;
	}

	private synchronized Object
	exactName(Name name) {
	return data.get(name);
	}

	private synchronized RRset []
	allRRsets(Object types) {
	if (types instanceof List) {
	List typelist = (List) types;
	return (RRset []) typelist.toArray(new RRset[typelist.size()]);
	} else {
	RRset set = (RRset) types;
	return new RRset [] {set};
	}
	}

	private synchronized RRset
	oneRRset(Object types, int type) {
	if (type == Type.ANY)
	throw new IllegalArgumentException("oneRRset(ANY)");
	if (types instanceof List) {
	List list = (List) types;
	for (int i = 0; i < list.size(); i++) {
	RRset set = (RRset) list.get(i);
	if (set.getType() == type)
	return set;
	}
	} else {
	RRset set = (RRset) types;
	if (set.getType() == type)
	return set;
	}
	return null;
	}

	private synchronized RRset
	findRRset(Name name, int type) {
	Object types = exactName(name);
	if (types == null)
	return null;
	return oneRRset(types, type);
	}

	private synchronized void
	addRRset(Name name, RRset rrset) {
	if (!hasWild && name.isWild())
	hasWild = true;
	Object types = data.get(name);
	if (types == null) {
	data.put(name, rrset);
	return;
	}
	int rtype = rrset.getType();
	if (types instanceof List) {
	List list = (List) types;
	for (int i = 0; i < list.size(); i++) {
	RRset set = (RRset) list.get(i);
	if (set.getType() == rtype) {
	list.set(i, rrset);
	return;
	}
	}
	list.add(rrset);
	} else {
	RRset set = (RRset) types;
	if (set.getType() == rtype)
	data.put(name, rrset);
	else {
	LinkedList list = new LinkedList();
	list.add(set);
	list.add(rrset);
	data.put(name, list);
	}
	}
	}

	private synchronized void
	removeRRset(Name name, int type) {
	Object types = data.get(name);
	if (types == null) {
	return;
	}
	if (types instanceof List) {
	List list = (List) types;
	for (int i = 0; i < list.size(); i++) {
	RRset set = (RRset) list.get(i);
	if (set.getType() == type) {
	list.remove(i);
	if (list.size() == 0)
	data.remove(name);
	return;
	}
	}
	} else {
	RRset set = (RRset) types;
	if (set.getType() != type)
	return;
	data.remove(name);
	}
	}

	private synchronized SetResponse
	lookup(Name name, int type) {
	int labels;
	int olabels;
	int tlabels;
	RRset rrset;
	Name tname;
	Object types;
	SetResponse sr;

	if (!name.subdomain(origin))
	return SetResponse.ofType(SetResponse.NXDOMAIN);

	labels = name.labels();
	olabels = origin.labels();

	for (tlabels = olabels; tlabels <= labels; tlabels++) {
	boolean isOrigin = (tlabels == olabels);
	boolean isExact = (tlabels == labels);

	if (isOrigin)
	tname = origin;
	else if (isExact)
	tname = name;
	else
	tname = new Name(name, labels - tlabels);

	types = exactName(tname);
	if (types == null)
	continue;

	/* If this is a delegation, return that. */
	if (!isOrigin) {
	RRset ns = oneRRset(types, Type.NS);
	if (ns != null)
	return new SetResponse(SetResponse.DELEGATION,
	ns);
	}

	/* If this is an ANY lookup, return everything. */
	if (isExact && type == Type.ANY) {
	sr = new SetResponse(SetResponse.SUCCESSFUL);
	RRset [] sets = allRRsets(types);
	for (int i = 0; i < sets.length; i++)
	sr.addRRset(sets[i]);
	return sr;
	}

	/*
	* If this is the name, look for the actual type or a CNAME.
	* Otherwise, look for a DNAME.
	*/
	if (isExact) {
	rrset = oneRRset(types, type);
	if (rrset != null) {
	sr = new SetResponse(SetResponse.SUCCESSFUL);
	sr.addRRset(rrset);
	return sr;
	}
	rrset = oneRRset(types, Type.CNAME);
	if (rrset != null)
	return new SetResponse(SetResponse.CNAME,
	rrset);
	} else {
	rrset = oneRRset(types, Type.DNAME);
	if (rrset != null)
	return new SetResponse(SetResponse.DNAME,
	rrset);
	}

	/* We found the name, but not the type. */
	if (isExact)
	return SetResponse.ofType(SetResponse.NXRRSET);
	}

	if (hasWild) {
	for (int i = 0; i < labels - olabels; i++) {
	tname = name.wild(i + 1);

	types = exactName(tname);
	if (types == null)
	continue;

	rrset = oneRRset(types, type);
	if (rrset != null) {
	sr = new SetResponse(SetResponse.SUCCESSFUL);
	sr.addRRset(rrset);
	return sr;
	}
	}
	}

	return SetResponse.ofType(SetResponse.NXDOMAIN);
	}

	/**
	* Looks up Records in the Zone. This follows CNAMEs and wildcards.
	* @param name The name to look up
	* @param type The type to look up
	* @return A SetResponse object
	* @see SetResponse
	*/
	public SetResponse
	findRecords(Name name, int type) {
	return lookup(name, type);
	}

	/**
	* Looks up Records in the zone, finding exact matches only.
	* @param name The name to look up
	* @param type The type to look up
	* @return The matching RRset
	* @see RRset
	*/
	public RRset
	findExactMatch(Name name, int type) {
	Object types = exactName(name);
	if (types == null)
	return null;
	return oneRRset(types, type);
	}

	/**
	* Adds an RRset to the Zone
	* @param rrset The RRset to be added
	* @see RRset
	*/
	public void
	addRRset(RRset rrset) {
	Name name = rrset.getName();
	addRRset(name, rrset);
	}

	/**
	* Adds a Record to the Zone
	* @param r The record to be added
	* @see Record
	*/
	public void
	addRecord(Record r) {
	Name name = r.getName();
	int rtype = r.getRRsetType();
	synchronized (this) {
	RRset rrset = findRRset(name, rtype);
	if (rrset == null) {
	rrset = new RRset(r);
	addRRset(name, rrset);
	} else {
	rrset.addRR(r);
	}
	}
	}

	/**
	* Removes a record from the Zone
	* @param r The record to be removed
	* @see Record
	*/
	public void
	removeRecord(Record r) {
	Name name = r.getName();
	int rtype = r.getRRsetType();
	synchronized (this) {
	RRset rrset = findRRset(name, rtype);
	if (rrset == null)
	return;
	if (rrset.size() == 1 && rrset.first().equals(r))
	removeRRset(name, rtype);
	else
	rrset.deleteRR(r);
	}
	}

	/**
	* Returns an Iterator over the RRsets in the zone.
	*/
	public Iterator
	iterator() {
	return new ZoneIterator(false);
	}

	/**
	* Returns an Iterator over the RRsets in the zone that can be used to
	* construct an AXFR response. This is identical to {@link #iterator} except
	* that the SOA is returned at the end as well as the beginning.
	*/
	public Iterator
	AXFR() {
	return new ZoneIterator(true);
	}

	private void
	nodeToString(StringBuffer sb, Object node) {
	RRset [] sets = allRRsets(node);
	for (int i = 0; i < sets.length; i++) {
	RRset rrset = sets[i];
	Iterator it = rrset.rrs();
	while (it.hasNext())
	sb.append(it.next() + "\n");
	it = rrset.sigs();
	while (it.hasNext())
	sb.append(it.next() + "\n");
	}
	}

	/**
	* Returns the contents of the Zone in master file format.
	*/
	public synchronized String
	toMasterFile() {
	Iterator zentries = data.entrySet().iterator();
	StringBuffer sb = new StringBuffer();
	nodeToString(sb, originNode);
	while (zentries.hasNext()) {
	Map.Entry entry = (Map.Entry) zentries.next();
	if (!origin.equals(entry.getKey()))
	nodeToString(sb, entry.getValue());
	}
	return sb.toString();
	}

	/**
	* Returns the contents of the Zone as a string (in master file format).
	*/
	public String
	toString() {
	return toMasterFile();
	}

	}