HADOOP-351. Make IPC code independent of Jetty. Contributed by Devaraj Das.

git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk@423443 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -55,6 +55,8 @@ Trunk (unreleased changes)
     redirected to datanodes where the data is local when possible.
     (Devaraj Das via cutting)
 
+16. HADOOP-351.  Make Hadoop IPC kernel independent of Jetty.
+    (Devaraj Das via cutting)
 
 Release 0.4.0 - 2006-06-28
 

src/java/org/apache/hadoop/ipc/Server.java

@@ -47,8 +47,7 @@ import org.apache.hadoop.conf.Configurable;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableUtils;
-
-import org.mortbay.http.nio.SocketChannelOutputStream;
+import org.apache.hadoop.ipc.SocketChannelOutputStream;
 
 /** An abstract IPC service.  IPC calls take a single {@link Writable} as a
  * parameter, and return a {@link Writable} as their value.  A service runs on

src/java/org/apache/hadoop/ipc/SocketChannelOutputStream.java

@@ -0,0 +1,158 @@
+/**
+ * Licensed 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.
+ */
+
+package org.apache.hadoop.ipc;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.SocketChannel;
+
+/* ------------------------------------------------------------------------------- */
+/** 
+ * Blocking output stream on non-blocking SocketChannel.  Makes the 
+ * assumption that writes will rarely need to block.
+ * All writes flush to the channel, and no additional buffering is done.
+ */
+class SocketChannelOutputStream extends OutputStream {    
+    
+    ByteBuffer buffer;
+    ByteBuffer flush;
+    SocketChannel channel;
+    Selector selector;
+    
+    /* ------------------------------------------------------------------------------- */
+    /** Constructor.
+     * 
+     */
+    public SocketChannelOutputStream(SocketChannel channel, int bufferSize)
+    {
+        this.channel = channel;
+        buffer = ByteBuffer.allocateDirect(bufferSize);
+    }
+
+    /* ------------------------------------------------------------------------------- */
+    /*
+     * @see java.io.OutputStream#write(int)
+     */
+    public void write(int b) throws IOException
+    {
+        buffer.clear();
+        buffer.put((byte)b);
+        buffer.flip();
+        flush = buffer;
+        flushBuffer();
+    }
+
+    
+    /* ------------------------------------------------------------------------------- */
+    /*
+     * @see java.io.OutputStream#close()
+     */
+    public void close() throws IOException
+    {
+        channel.close();
+    }
+
+    /* ------------------------------------------------------------------------------- */
+    /*
+     * @see java.io.OutputStream#flush()
+     */
+    public void flush() throws IOException
+    {
+    }
+
+    /* ------------------------------------------------------------------------------- */
+    /*
+     * @see java.io.OutputStream#write(byte[], int, int)
+     */
+    public void write(byte[] buf, int offset, int length) throws IOException
+    {
+        if (length > buffer.capacity())
+            flush = ByteBuffer.wrap(buf,offset,length);
+        else
+         {
+             buffer.clear();
+             buffer.put(buf,offset,length);
+             buffer.flip();
+             flush = buffer;
+         }
+         flushBuffer();
+    }
+
+    /* ------------------------------------------------------------------------------- */
+    /*
+     * @see java.io.OutputStream#write(byte[])
+     */
+    public void write(byte[] buf) throws IOException
+    {
+        if (buf.length > buffer.capacity())
+            flush = ByteBuffer.wrap(buf);
+        else
+         {
+             buffer.clear();
+             buffer.put(buf);
+             buffer.flip();
+             flush = buffer;
+         }
+         flushBuffer();
+    }
+
+
+    /* ------------------------------------------------------------------------------- */
+    private void flushBuffer() throws IOException
+    {
+        while (flush.hasRemaining())
+        {
+            int len = channel.write(flush);
+            if (len < 0)
+                throw new IOException("EOF");
+            if (len == 0)
+            {
+                // write channel full.  Try letting other threads have a go.
+                Thread.yield();
+                len = channel.write(flush);
+                if (len < 0)
+                    throw new IOException("EOF");
+                if (len == 0)
+                {
+                    // still full.  need to  block until it is writable.
+                    if (selector==null)
+                     {
+                            selector = Selector.open();
+                            channel.register(selector, SelectionKey.OP_WRITE);
+                     }
+
+                     selector.select();
+                }
+            }
+        }
+    }
+
+    /* ------------------------------------------------------------------------------- */
+    public void destroy()
+    {
+        if (selector != null)
+        {
+            try{ selector.close();}
+            catch(IOException e){}
+            selector = null;
+            buffer = null;
+            flush = null;
+            channel = null;
+        }
+    }
+}