2 import java.util.HashMap;
4 import java.util.Iterator;
5 import java.util.HashSet;
6 import java.util.Arrays;
7 import java.util.Vector;
10 * IoTTable data structure. Provides client inferface.
11 * @author Brian Demsky
16 final public class Table {
18 private HashMap<IoTString, KeyValue> table=new HashMap<IoTString, KeyValue>();
19 private HashMap<Long, Pair<Long, Liveness> > lastmessagetable=new HashMap<Long, Pair<Long, Liveness> >();
20 private HashMap<Long, HashSet<RejectedMessage> > watchlist = new HashMap<Long, HashSet<RejectedMessage> >();
21 private SlotBuffer buffer;
22 private CloudComm cloud;
23 private long sequencenumber;
24 private long localmachineid;
25 private TableStatus lastTableStatus;
26 static final int FREE_SLOTS = 10;
27 static final int FORCED_RESIZE_INCREMENT = 20;
29 public Table(String baseurl, String password, long _localmachineid) {
30 localmachineid=_localmachineid;
31 buffer = new SlotBuffer();
32 numslots = buffer.capacity();
34 cloud=new CloudComm(baseurl, password);
37 public Table(CloudComm _cloud, long _localmachineid) {
38 localmachineid=_localmachineid;
39 buffer = new SlotBuffer();
40 numslots = buffer.capacity();
45 public void rebuild() {
46 Slot[] newslots=cloud.getSlots(sequencenumber+1);
47 validateandupdate(newslots, true);
50 public void update() {
51 Slot[] newslots=cloud.getSlots(sequencenumber+1);
53 validateandupdate(newslots, false);
56 public IoTString get(IoTString key) {
57 KeyValue kv=table.get(key);
64 public void initTable() {
65 Slot s=new Slot(1, localmachineid);
66 TableStatus status=new TableStatus(s, numslots);
68 Slot[] array=cloud.putSlot(s, numslots);
70 array = new Slot[] {s};
71 /* update data structure */
72 validateandupdate(array, true);
74 throw new Error("Error on initialization");
78 public String toString() {
79 return table.toString();
82 public IoTString put(IoTString key, IoTString value) {
84 KeyValue oldvalue=table.get(key);
85 if (tryput(key, value, false)) {
89 return oldvalue.getValue();
94 private boolean tryput(IoTString key, IoTString value, boolean forcedresize) {
95 Slot s=new Slot(sequencenumber+1, localmachineid, buffer.getSlot(sequencenumber).getHMAC());
96 long seqn = buffer.getOldestSeqNum();
99 TableStatus status=new TableStatus(s, FORCED_RESIZE_INCREMENT + numslots);
103 if ((numslots - buffer.size()) < FREE_SLOTS) {
104 /* have to check whether we have enough free slots */
105 long fullfirstseqn = buffer.getNewestSeqNum() + 1 - numslots;
106 seqn = fullfirstseqn < 1?1:fullfirstseqn;
107 for(int i=0; i < FREE_SLOTS; i++, seqn++) {
108 Slot prevslot=buffer.getSlot(seqn);
109 if (!prevslot.isLive())
111 Vector<Entry> liveentries = prevslot.getLiveEntries();
112 for(Entry liveentry:liveentries) {
113 if (s.hasSpace(liveentry))
114 s.addEntry(liveentry);
116 if (s.canFit(liveentry))
117 s.addEntry(liveentry);
118 else if (!forcedresize) {
119 return tryput(key, value, true);
125 KeyValue kv=new KeyValue(s, key, value);
126 boolean insertedkv=false;
127 if (s.hasSpace(kv)) {
132 long newestseqnum=buffer.getNewestSeqNum();
134 for(; seqn<=newestseqnum; seqn++) {
135 Slot prevslot=buffer.getSlot(seqn);
136 if (!prevslot.isLive())
138 Vector<Entry> liveentries = prevslot.getLiveEntries();
139 for(Entry liveentry:liveentries) {
140 if (s.hasSpace(liveentry))
141 s.addEntry(liveentry);
149 max = numslots + FORCED_RESIZE_INCREMENT;
150 Slot[] array=cloud.putSlot(s, max);
152 array = new Slot[] {s};
156 /* update data structure */
157 validateandupdate(array, true);
162 private void validateandupdate(Slot[] newslots, boolean acceptupdatestolocal) {
163 /* The cloud communication layer has checked slot HMACs already
165 if (newslots.length==0)
168 long firstseqnum=newslots[0].getSequenceNumber();
169 if (firstseqnum <= sequencenumber)
170 throw new Error("Server Error: Sent older slots!");
172 SlotIndexer indexer = new SlotIndexer(newslots, buffer);
173 checkHMACChain(indexer, newslots);
175 HashSet<Long> machineSet=new HashSet<Long>(lastmessagetable.keySet());
178 for(Slot slot: newslots) {
179 updateExpectedSize();
180 processSlot(indexer, slot, acceptupdatestolocal, machineSet);
183 /* If there is a gap, check to see if the server sent us everything. */
184 if (firstseqnum != (sequencenumber+1)) {
185 checkNumSlots(newslots.length);
186 if (!machineSet.isEmpty())
187 throw new Error("Missing record for machines: "+machineSet);
192 /* Commit new to slots. */
193 for(Slot slot:newslots) {
194 buffer.putSlot(slot);
196 sequencenumber = newslots[newslots.length - 1].getSequenceNumber();
199 private int expectedsize, currmaxsize;
201 private void checkNumSlots(int numslots) {
202 if (numslots != expectedsize)
203 throw new Error("Server Error: Server did not send all slots. Expected: "+expectedsize+" Received:"+numslots);
206 private void initExpectedSize() {
207 long prevslots = sequencenumber;
208 expectedsize = (prevslots < ((long) numslots))?(int) prevslots:numslots;
209 currmaxsize = numslots;
212 private void updateExpectedSize() {
214 if (expectedsize > currmaxsize)
215 expectedsize = currmaxsize;
218 private void updateCurrMaxSize(int newmaxsize) {
219 currmaxsize=newmaxsize;
222 private void commitNewMaxSize() {
223 if (numslots != currmaxsize)
224 buffer.resize(currmaxsize);
226 numslots=currmaxsize;
229 private void processEntry(KeyValue entry, SlotIndexer indexer) {
230 IoTString key=entry.getKey();
231 KeyValue oldvalue=table.get(key);
232 if (oldvalue != null) {
235 table.put(key, entry);
238 private void processEntry(LastMessage entry, SlotIndexer indexer, HashSet<Long> machineSet) {
239 updateLastMessage(entry.getMachineID(), entry.getSequenceNumber(), entry, false, machineSet);
242 private void processEntry(RejectedMessage entry, SlotIndexer indexer) {
243 long oldseqnum=entry.getOldSeqNum();
244 long newseqnum=entry.getNewSeqNum();
245 boolean isequal=entry.getEqual();
246 long machineid=entry.getMachineID();
247 for(long seqnum=oldseqnum; seqnum<=newseqnum; seqnum++) {
248 Slot slot=indexer.getSlot(seqnum);
250 long slotmachineid=slot.getMachineID();
251 if (isequal!=(slotmachineid==machineid)) {
252 throw new Error("Server Error: Trying to insert rejected message for slot "+seqnum);
257 HashSet<Long> watchset=new HashSet<Long>();
258 for(Map.Entry<Long, Pair<Long,Liveness> > lastmsg_entry:lastmessagetable.entrySet()) {
259 long entry_mid=lastmsg_entry.getKey();
260 /* We've seen it, don't need to continue to watch. Our next
261 * message will implicitly acknowledge it. */
262 if (entry_mid == localmachineid)
264 Pair<Long, Liveness> v=lastmsg_entry.getValue();
265 long entry_seqn=v.getFirst();
266 if (entry_seqn < newseqnum) {
267 addWatchList(entry_mid, entry);
268 watchset.add(entry_mid);
271 if (watchset.isEmpty())
274 entry.setWatchSet(watchset);
277 private void addWatchList(long machineid, RejectedMessage entry) {
278 HashSet<RejectedMessage> entries=watchlist.get(machineid);
280 watchlist.put(machineid, entries=new HashSet<RejectedMessage>());
284 private void processEntry(TableStatus entry, SlotIndexer indexer) {
285 int newnumslots=entry.getMaxSlots();
286 updateCurrMaxSize(newnumslots);
287 if (lastTableStatus != null)
288 lastTableStatus.setDead();
289 lastTableStatus = entry;
292 private void updateLastMessage(long machineid, long seqnum, Liveness liveness, boolean acceptupdatestolocal, HashSet<Long> machineSet) {
293 machineSet.remove(machineid);
295 HashSet<RejectedMessage> watchset=watchlist.get(machineid);
296 if (watchset != null) {
297 for(Iterator<RejectedMessage> rmit=watchset.iterator(); rmit.hasNext(); ) {
298 RejectedMessage rm=rmit.next();
299 if (rm.getNewSeqNum() <= seqnum) {
300 /* Remove it from our watchlist */
302 /* Decrement machines that need to see this notification */
303 rm.removeWatcher(machineid);
308 if (machineid == localmachineid) {
309 /* Our own messages are immediately dead. */
310 if (liveness instanceof LastMessage) {
311 ((LastMessage)liveness).setDead();
312 } else if (liveness instanceof Slot) {
313 ((Slot)liveness).setDead();
315 throw new Error("Unrecognized type");
320 Pair<Long, Liveness> lastmsgentry = lastmessagetable.put(machineid, new Pair<Long, Liveness>(seqnum, liveness));
321 if (lastmsgentry == null)
324 long lastmsgseqnum = lastmsgentry.getFirst();
325 Liveness lastentry = lastmsgentry.getSecond();
326 if (machineid != localmachineid) {
327 if (lastentry instanceof LastMessage) {
328 ((LastMessage)lastentry).setDead();
329 } else if (lastentry instanceof Slot) {
330 ((Slot)lastentry).setDead();
332 throw new Error("Unrecognized type");
336 if (machineid == localmachineid) {
337 if (lastmsgseqnum != seqnum && !acceptupdatestolocal)
338 throw new Error("Server Error: Mismatch on local machine sequence number");
340 if (lastmsgseqnum > seqnum)
341 throw new Error("Server Error: Rollback on remote machine sequence number");
345 private void processSlot(SlotIndexer indexer, Slot slot, boolean acceptupdatestolocal, HashSet<Long> machineSet) {
346 updateLastMessage(slot.getMachineID(), slot.getSequenceNumber(), slot, acceptupdatestolocal, machineSet);
347 for(Entry entry : slot.getEntries()) {
348 switch(entry.getType()) {
349 case Entry.TypeKeyValue:
350 processEntry((KeyValue)entry, indexer);
353 case Entry.TypeLastMessage:
354 processEntry((LastMessage)entry, indexer, machineSet);
357 case Entry.TypeRejectedMessage:
358 processEntry((RejectedMessage)entry, indexer);
361 case Entry.TypeTableStatus:
362 processEntry((TableStatus)entry, indexer);
366 throw new Error("Unrecognized type: "+entry.getType());
371 private void checkHMACChain(SlotIndexer indexer, Slot[] newslots) {
372 for(int i=0; i < newslots.length; i++) {
373 Slot currslot=newslots[i];
374 Slot prevslot=indexer.getSlot(currslot.getSequenceNumber()-1);
375 if (prevslot != null &&
376 !Arrays.equals(prevslot.getHMAC(), currslot.getPrevHMAC()))
377 throw new Error("Server Error: Invalid HMAC Chain"+currslot+" "+prevslot);