Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | // Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org) |
| 2 | |
| 3 | package org.xbill.DNS; |
| 4 | |
| 5 | import java.io.Serializable; |
| 6 | import java.util.*; |
| 7 | |
| 8 | /** |
| 9 | * A set of Records with the same name, type, and class. Also included |
| 10 | * are all RRSIG records signing the data records. |
| 11 | * @see Record |
| 12 | * @see RRSIGRecord |
| 13 | * |
| 14 | * @author Brian Wellington |
| 15 | */ |
| 16 | |
| 17 | public class RRset implements Serializable { |
| 18 | |
| 19 | private static final long serialVersionUID = -3270249290171239695L; |
| 20 | |
| 21 | /* |
| 22 | * rrs contains both normal and RRSIG records, with the RRSIG records |
| 23 | * at the end. |
| 24 | */ |
| 25 | private List rrs; |
| 26 | private short nsigs; |
| 27 | private short position; |
| 28 | |
| 29 | /** Creates an empty RRset */ |
| 30 | public |
| 31 | RRset() { |
| 32 | rrs = new ArrayList(1); |
| 33 | nsigs = 0; |
| 34 | position = 0; |
| 35 | } |
| 36 | |
| 37 | /** Creates an RRset and sets its contents to the specified record */ |
| 38 | public |
| 39 | RRset(Record record) { |
| 40 | this(); |
| 41 | safeAddRR(record); |
| 42 | } |
| 43 | |
| 44 | /** Creates an RRset with the contents of an existing RRset */ |
| 45 | public |
| 46 | RRset(RRset rrset) { |
| 47 | synchronized (rrset) { |
| 48 | rrs = (List) ((ArrayList)rrset.rrs).clone(); |
| 49 | nsigs = rrset.nsigs; |
| 50 | position = rrset.position; |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | private void |
| 55 | safeAddRR(Record r) { |
| 56 | if (!(r instanceof RRSIGRecord)) { |
| 57 | if (nsigs == 0) |
| 58 | rrs.add(r); |
| 59 | else |
| 60 | rrs.add(rrs.size() - nsigs, r); |
| 61 | } else { |
| 62 | rrs.add(r); |
| 63 | nsigs++; |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | /** Adds a Record to an RRset */ |
| 68 | public synchronized void |
| 69 | addRR(Record r) { |
| 70 | if (rrs.size() == 0) { |
| 71 | safeAddRR(r); |
| 72 | return; |
| 73 | } |
| 74 | Record first = first(); |
| 75 | if (!r.sameRRset(first)) |
| 76 | throw new IllegalArgumentException("record does not match " + |
| 77 | "rrset"); |
| 78 | |
| 79 | if (r.getTTL() != first.getTTL()) { |
| 80 | if (r.getTTL() > first.getTTL()) { |
| 81 | r = r.cloneRecord(); |
| 82 | r.setTTL(first.getTTL()); |
| 83 | } else { |
| 84 | for (int i = 0; i < rrs.size(); i++) { |
| 85 | Record tmp = (Record) rrs.get(i); |
| 86 | tmp = tmp.cloneRecord(); |
| 87 | tmp.setTTL(r.getTTL()); |
| 88 | rrs.set(i, tmp); |
| 89 | } |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | if (!rrs.contains(r)) |
| 94 | safeAddRR(r); |
| 95 | } |
| 96 | |
| 97 | /** Deletes a Record from an RRset */ |
| 98 | public synchronized void |
| 99 | deleteRR(Record r) { |
| 100 | if (rrs.remove(r) && (r instanceof RRSIGRecord)) |
| 101 | nsigs--; |
| 102 | } |
| 103 | |
| 104 | /** Deletes all Records from an RRset */ |
| 105 | public synchronized void |
| 106 | clear() { |
| 107 | rrs.clear(); |
| 108 | position = 0; |
| 109 | nsigs = 0; |
| 110 | } |
| 111 | |
| 112 | private synchronized Iterator |
| 113 | iterator(boolean data, boolean cycle) { |
| 114 | int size, start, total; |
| 115 | |
| 116 | total = rrs.size(); |
| 117 | |
| 118 | if (data) |
| 119 | size = total - nsigs; |
| 120 | else |
| 121 | size = nsigs; |
| 122 | if (size == 0) |
| 123 | return Collections.EMPTY_LIST.iterator(); |
| 124 | |
| 125 | if (data) { |
| 126 | if (!cycle) |
| 127 | start = 0; |
| 128 | else { |
| 129 | if (position >= size) |
| 130 | position = 0; |
| 131 | start = position++; |
| 132 | } |
| 133 | } else { |
| 134 | start = total - nsigs; |
| 135 | } |
| 136 | |
| 137 | List list = new ArrayList(size); |
| 138 | if (data) { |
| 139 | list.addAll(rrs.subList(start, size)); |
| 140 | if (start != 0) |
| 141 | list.addAll(rrs.subList(0, start)); |
| 142 | } else { |
| 143 | list.addAll(rrs.subList(start, total)); |
| 144 | } |
| 145 | |
| 146 | return list.iterator(); |
| 147 | } |
| 148 | |
| 149 | /** |
| 150 | * Returns an Iterator listing all (data) records. |
| 151 | * @param cycle If true, cycle through the records so that each Iterator will |
| 152 | * start with a different record. |
| 153 | */ |
| 154 | public synchronized Iterator |
| 155 | rrs(boolean cycle) { |
| 156 | return iterator(true, cycle); |
| 157 | } |
| 158 | |
| 159 | /** |
| 160 | * Returns an Iterator listing all (data) records. This cycles through |
| 161 | * the records, so each Iterator will start with a different record. |
| 162 | */ |
| 163 | public synchronized Iterator |
| 164 | rrs() { |
| 165 | return iterator(true, true); |
| 166 | } |
| 167 | |
| 168 | /** Returns an Iterator listing all signature records */ |
| 169 | public synchronized Iterator |
| 170 | sigs() { |
| 171 | return iterator(false, false); |
| 172 | } |
| 173 | |
| 174 | /** Returns the number of (data) records */ |
| 175 | public synchronized int |
| 176 | size() { |
| 177 | return rrs.size() - nsigs; |
| 178 | } |
| 179 | |
| 180 | /** |
| 181 | * Returns the name of the records |
| 182 | * @see Name |
| 183 | */ |
| 184 | public Name |
| 185 | getName() { |
| 186 | return first().getName(); |
| 187 | } |
| 188 | |
| 189 | /** |
| 190 | * Returns the type of the records |
| 191 | * @see Type |
| 192 | */ |
| 193 | public int |
| 194 | getType() { |
| 195 | return first().getRRsetType(); |
| 196 | } |
| 197 | |
| 198 | /** |
| 199 | * Returns the class of the records |
| 200 | * @see DClass |
| 201 | */ |
| 202 | public int |
| 203 | getDClass() { |
| 204 | return first().getDClass(); |
| 205 | } |
| 206 | |
| 207 | /** Returns the ttl of the records */ |
| 208 | public synchronized long |
| 209 | getTTL() { |
| 210 | return first().getTTL(); |
| 211 | } |
| 212 | |
| 213 | /** |
| 214 | * Returns the first record |
| 215 | * @throws IllegalStateException if the rrset is empty |
| 216 | */ |
| 217 | public synchronized Record |
| 218 | first() { |
| 219 | if (rrs.size() == 0) |
| 220 | throw new IllegalStateException("rrset is empty"); |
| 221 | return (Record) rrs.get(0); |
| 222 | } |
| 223 | |
| 224 | private String |
| 225 | iteratorToString(Iterator it) { |
| 226 | StringBuffer sb = new StringBuffer(); |
| 227 | while (it.hasNext()) { |
| 228 | Record rr = (Record) it.next(); |
| 229 | sb.append("["); |
| 230 | sb.append(rr.rdataToString()); |
| 231 | sb.append("]"); |
| 232 | if (it.hasNext()) |
| 233 | sb.append(" "); |
| 234 | } |
| 235 | return sb.toString(); |
| 236 | } |
| 237 | |
| 238 | /** Converts the RRset to a String */ |
| 239 | public String |
| 240 | toString() { |
| 241 | if (rrs == null) |
| 242 | return ("{empty}"); |
| 243 | StringBuffer sb = new StringBuffer(); |
| 244 | sb.append("{ "); |
| 245 | sb.append(getName() + " "); |
| 246 | sb.append(getTTL() + " "); |
| 247 | sb.append(DClass.string(getDClass()) + " "); |
| 248 | sb.append(Type.string(getType()) + " "); |
| 249 | sb.append(iteratorToString(iterator(true, false))); |
| 250 | if (nsigs > 0) { |
| 251 | sb.append(" sigs: "); |
| 252 | sb.append(iteratorToString(iterator(false, false))); |
| 253 | } |
| 254 | sb.append(" }"); |
| 255 | return sb.toString(); |
| 256 | } |
| 257 | |
| 258 | } |