Add support for a synchronous delete, via observe operation.

This change adds support for a synchronous delete, including
detection of full delete versus logical delete.

The main use case behind this feature is that if using
Couchbase Server 2.0, and wanting to query views, one may
wish to ensure a delete has been persisted to know that
a subsequent query with .setStale(false) will take the
deletion into account when generating the index.

Change-Id: I99ad5b5089992a7df2c2ab12e487d043265df21f
Reviewed-on: http://review.couchbase.org/19778
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Tested-by: Matt Ingenthron <matt@couchbase.com>

src/main/java/com/couchbase/client/CouchbaseClient.java

@@ -59,6 +59,7 @@
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicReference;
@@ -805,6 +806,47 @@ public Boolean unlock(final String key,
     return unlock(key, casId, transcoder);
   }
 
+  /**
+   * Delete a value and Observe.
+   *
+   * @param key the key to set
+   * @param req the Persistence to Master value
+   * @param rep the Persistence to Replicas
+   * @return whether or not the operation was performed
+   *
+   */
+  public Future<Boolean> delete(String key,
+          PersistTo req, ReplicateTo rep) {
+    OperationFuture<Boolean> deleteOp = delete(key);
+    try {
+      if (deleteOp.get()) {
+        observePoll(key, 0L, req, rep);
+      }
+    } catch (InterruptedException e) {
+      deleteOp.set(false, deleteOp.getStatus());
+    } catch (ExecutionException e) {
+      deleteOp.set(false, deleteOp.getStatus());
+    } catch (TimeoutException e) {
+      deleteOp.set(false, deleteOp.getStatus());
+    } catch (IllegalArgumentException e) {
+      deleteOp.set(false, deleteOp.getStatus());
+    } catch (RuntimeException e) {
+      deleteOp.set(false, deleteOp.getStatus());
+    }
+    return (deleteOp);
+  }
+/**
+   * Delete a value with Observe.
+   *
+   * @param key the key to set
+   * @param req the Persistence to Master value
+   * @return whether or not the operation was performed
+   *
+   */
+  public Future<Boolean> delete(String key, PersistTo req) {
+    return delete(key, req, ReplicateTo.ZERO);
+  }
+
   /**
    * Set a value and Observe.
    *
@@ -1028,6 +1070,7 @@ private void observePoll(String key, long cas,
     // Other than Master
     switch (persist) {
     case MASTER:
+    case ONE:
       persists=0;
       break;
     case TWO:
@@ -1096,7 +1139,7 @@ private void observePoll(String key, long cas,
       try {
         Thread.sleep(400);
       } catch (InterruptedException e) {
-         getLogger().error("Interrupted while in observe loop.", e);
+        getLogger().error("Interrupted while in observe loop.", e);
       }
     } while (loop++ < 10);
 

src/main/java/com/couchbase/client/CouchbaseClientIF.java

@@ -67,5 +67,9 @@ OperationFuture<Boolean> set(String key, int exp,
           String value, PersistTo persist);
   OperationFuture<Boolean> set(String key, int exp,
           String value, PersistTo persist, ReplicateTo replicate);
+  Future<Boolean> delete(String key, PersistTo persist);
+  Future<Boolean> delete(String key, PersistTo persist,
+          ReplicateTo replicate);
+
   int getNumVBuckets();
 }