add contrib example of using "fat client" api. patch by gdusbabek; reviewed by jbellis for CASSANDRA-596

git-svn-id: https://svn.apache.org/repos/asf/incubator/cassandra/trunk@887456 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -10,6 +10,7 @@
  * fix returning live subcolumns of deleted supercolumns (CASSANDRA-583)
  * respect JAVA_HOME in bin/ scripts (several tickets)
  * add StorageService.initClient for fat clients on the JVM (CASSANDRA-535)
+   (see contrib/client_only for an example of use)
 
 
 0.5.0 beta

contrib/client_only/ClientOnlyExample.java

@@ -0,0 +1,168 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.cassandra.db.*;
+import org.apache.cassandra.db.filter.QueryPath;
+import org.apache.cassandra.db.marshal.AbstractType;
+import org.apache.cassandra.service.*;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+public class ClientOnlyExample
+{
+
+    private static void testWriting() throws IOException
+    {
+        StorageService.instance().initClient();
+        // sleep for a bit so that gossip can do its thing.
+        try
+        {
+            Thread.sleep(10000L);
+        }
+        catch (Exception ex)
+        {
+        }
+
+        // do some writing.
+        final AbstractType comp = ColumnFamily.getComparatorFor("Keyspace1", "Standard1", null);
+        for (int i = 0; i < 100; i++)
+        {
+            RowMutation change = new RowMutation("Keyspace1", "key" + i);
+            ColumnPath cp = new ColumnPath("Standard1", null, ("colb").getBytes());
+            change.add(new QueryPath(cp), ("value" + i).getBytes(), 0);
+
+            // don't call change.apply().  The reason is that is makes a static call into Table, which will perform
+            // local storage initialization, which creates local directories.
+            // change.apply();
+
+            StorageProxy.insert(change);
+            try
+            {
+                Thread.sleep(50L);
+            }
+            catch (Exception ex)
+            {
+            }
+            System.out.println("wrote key" + i);
+        }
+        System.out.println("Done writing.");
+        StorageService.instance().stopClient();
+    }
+
+    private static void testReading() throws IOException
+    {
+        StorageService.instance().initClient();
+        // sleep for a bit so that gossip can do its thing.
+        try
+        {
+            Thread.sleep(10000L);
+        }
+        catch (Exception ex)
+        {
+        }
+
+        // do some queries.
+        Collection<byte[]> cols = new ArrayList<byte[]>()
+        {{
+            add("colb".getBytes());
+        }};
+        for (int i = 0; i < 100; i++)
+        {
+            List<ReadCommand> commands = new ArrayList<ReadCommand>();
+            SliceByNamesReadCommand readCommand = new SliceByNamesReadCommand("Keyspace1", "key" + i, new QueryPath("Standard1", null, null), cols);
+            readCommand.setDigestQuery(false);
+            commands.add(readCommand);
+            try
+            {
+                List<Row> rows = StorageProxy.readProtocol(commands, ConsistencyLevel.ONE);
+                assert rows.size() == 1;
+                Row row = rows.get(0);
+                ColumnFamily cf = row.cf;
+                if (cf != null)
+                {
+                    for (IColumn col : cf.getSortedColumns())
+                    {
+                        System.out.println(new String(col.name()) + ", " + new String(col.value()));
+                    }
+                }
+                else
+                    System.err.println("This output indicates that nothing was read.");
+            }
+            catch (UnavailableException e)
+            {
+                throw new RuntimeException(e);
+            }
+            catch (TimedOutException e)
+            {
+                throw new RuntimeException(e);
+            }
+
+        }
+
+        // no need to do this:
+        // StorageService.instance().decommission();
+        // do this instead:
+        StorageService.instance().stopClient();
+    }
+
+    /**
+     * First, bring one or more nodes up. Then run ClientOnlyExample with these VM arguments:
+     *
+     -Xms128M
+     -Xmx1G
+     -Dstorage-config=/Users/gary.dusbabek/cass-configs/trunk/conf3-client
+
+     Pass "write" or "read" into the program to exercise the various methods.
+
+     Caveats:
+
+     1.  Much of cassandra is not reentrant.  That is, you can't spin a client up, down, then back up in the same jvm.
+     2.  Because of the above, you still need to force-quit the process. StorageService.stopClient() doesn't (can't)
+         spin everything down.
+     */
+    public static void main(String args[])
+    {
+        if (args.length == 0)
+            System.out.println("run with \"read\" or \"write\".");
+        else if ("read".equalsIgnoreCase(args[0]))
+        {
+            try
+            {
+                testReading();
+            }
+            catch (IOException e)
+            {
+                throw new RuntimeException(e);
+            }
+        }
+        else if ("write".equalsIgnoreCase(args[0]))
+        {
+            try
+            {
+                testWriting();
+            }
+            catch (IOException e)
+            {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+}