HADOOP-4174. Move fs image/edit log methods from ClientProtocol to NamenodeProtocol. (shv via szetszwo)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@696040 13f79535-47bb-0310-9956-ffa450edef68

src/hdfs/org/apache/hadoop/hdfs/server/protocol/BlocksWithLocations.java

@@ -0,0 +1,117 @@
+/**
+ * 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.
+ */
+package org.apache.hadoop.hdfs.server.protocol;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import org.apache.hadoop.hdfs.protocol.Block;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.io.WritableUtils;
+
+/** A class to implement an array of BlockLocations
+ *  It provide efficient customized serialization/deserialization methods
+ *  in stead of using the default array (de)serialization provided by RPC
+ */
+public class BlocksWithLocations implements Writable {
+
+  /**
+   * A class to keep track of a block and its locations
+   */
+  public static class BlockWithLocations  implements Writable {
+    Block block;
+    String datanodeIDs[];
+    
+    /** default constructor */
+    public BlockWithLocations() {
+      block = new Block();
+      datanodeIDs = null;
+    }
+    
+    /** constructor */
+    public BlockWithLocations(Block b, String[] datanodes) {
+      block = b;
+      datanodeIDs = datanodes;
+    }
+    
+    /** get the block */
+    public Block getBlock() {
+      return block;
+    }
+    
+    /** get the block's locations */
+    public String[] getDatanodes() {
+      return datanodeIDs;
+    }
+    
+    /** deserialization method */
+    public void readFields(DataInput in) throws IOException {
+      block.readFields(in);
+      int len = WritableUtils.readVInt(in); // variable length integer
+      datanodeIDs = new String[len];
+      for(int i=0; i<len; i++) {
+        datanodeIDs[i] = Text.readString(in);
+      }
+    }
+    
+    /** serialization method */
+    public void write(DataOutput out) throws IOException {
+      block.write(out);
+      WritableUtils.writeVInt(out, datanodeIDs.length); // variable length int
+      for(String id:datanodeIDs) {
+        Text.writeString(out, id);
+      }
+    }
+  }
+
+  private BlockWithLocations[] blocks;
+
+  /** default constructor */
+  BlocksWithLocations() {
+  }
+
+  /** Constructor with one parameter */
+  public BlocksWithLocations( BlockWithLocations[] blocks ) {
+    this.blocks = blocks;
+  }
+
+  /** getter */
+  public BlockWithLocations[] getBlocks() {
+    return blocks;
+  }
+
+  /** serialization method */
+  public void write( DataOutput out ) throws IOException {
+    WritableUtils.writeVInt(out, blocks.length);
+    for(int i=0; i<blocks.length; i++) {
+      blocks[i].write(out);
+    }
+  }
+
+  /** deserialization method */
+  public void readFields(DataInput in) throws IOException {
+    int len = WritableUtils.readVInt(in);
+    blocks = new BlockWithLocations[len];
+    for(int i=0; i<len; i++) {
+      blocks[i] = new BlockWithLocations();
+      blocks[i].readFields(in);
+    }
+  }
+}