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/*
 * 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.accumulo.examples.simple.client;

import java.io.IOException;
import java.util.Map.Entry;

import org.apache.accumulo.core.Constants;
import org.apache.accumulo.core.client.AccumuloException;
import org.apache.accumulo.core.client.AccumuloSecurityException;
import org.apache.accumulo.core.client.BatchWriter;
import org.apache.accumulo.core.client.Connector;
import org.apache.accumulo.core.client.MutationsRejectedException;
import org.apache.accumulo.core.client.Scanner;
import org.apache.accumulo.core.client.TableExistsException;
import org.apache.accumulo.core.client.TableNotFoundException;
import org.apache.accumulo.core.client.ZooKeeperInstance;
import org.apache.accumulo.core.data.Key;
import org.apache.accumulo.core.data.Mutation;
import org.apache.accumulo.core.data.Range;
import org.apache.accumulo.core.data.Value;
import org.apache.hadoop.io.Text;
import org.apache.log4j.Logger;

/**
 * A demonstration of reading entire rows and deleting entire rows.
 */
public class RowOperations {
  
  private static final Logger log = Logger.getLogger(RowOperations.class);
  
  private static Connector connector;
  private static String table = "example";
  private static BatchWriter bw;
  
  public static void main(String[] args) throws AccumuloException, AccumuloSecurityException, TableExistsException, TableNotFoundException,
      MutationsRejectedException {
    if (args.length != 4) {
      log.error("Usage:    ");
      return;
    }
    
    // First the setup work
    connector = new ZooKeeperInstance(args[0], args[1]).getConnector(args[2], args[3].getBytes());
    
    // lets create an example table
    connector.tableOperations().create(table);
    
    // lets create 3 rows of information
    Text row1 = new Text("row1");
    Text row2 = new Text("row2");
    Text row3 = new Text("row3");
    
    // Which means 3 different mutations
    Mutation mut1 = new Mutation(row1);
    Mutation mut2 = new Mutation(row2);
    Mutation mut3 = new Mutation(row3);
    
    // And we'll put 4 columns in each row
    Text col1 = new Text("1");
    Text col2 = new Text("2");
    Text col3 = new Text("3");
    Text col4 = new Text("4");
    
    // Now we'll add them to the mutations
    mut1.put(new Text("column"), col1, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut1.put(new Text("column"), col2, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut1.put(new Text("column"), col3, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut1.put(new Text("column"), col4, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    
    mut2.put(new Text("column"), col1, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut2.put(new Text("column"), col2, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut2.put(new Text("column"), col3, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut2.put(new Text("column"), col4, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    
    mut3.put(new Text("column"), col1, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut3.put(new Text("column"), col2, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut3.put(new Text("column"), col3, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    mut3.put(new Text("column"), col4, System.currentTimeMillis(), new Value("This is the value for this key".getBytes()));
    
    // Now we'll make a Batch Writer
    bw = connector.createBatchWriter(table, 100000l, 30l, 1);
    
    // And add the mutations
    bw.addMutation(mut1);
    bw.addMutation(mut2);
    bw.addMutation(mut3);
    
    // Force a send
    bw.flush();
    
    // Now lets look at the rows
    Scanner rowThree = getRow(new Text("row3"));
    Scanner rowTwo = getRow(new Text("row2"));
    Scanner rowOne = getRow(new Text("row1"));
    
    // And print them
    log.info("This is everything");
    printRow(rowOne);
    printRow(rowTwo);
    printRow(rowThree);
    System.out.flush();
    
    // Now lets delete rowTwo with the iterator
    rowTwo = getRow(new Text("row2"));
    deleteRow(rowTwo);
    
    // Now lets look at the rows again
    rowThree = getRow(new Text("row3"));
    rowTwo = getRow(new Text("row2"));
    rowOne = getRow(new Text("row1"));
    
    // And print them
    log.info("This is row1 and row3");
    printRow(rowOne);
    printRow(rowTwo);
    printRow(rowThree);
    System.out.flush();
    
    // Should only see the two rows
    // Now lets delete rowOne without passing in the iterator
    
    deleteRow(row1);
    
    // Now lets look at the rows one last time
    rowThree = getRow(new Text("row3"));
    rowTwo = getRow(new Text("row2"));
    rowOne = getRow(new Text("row1"));
    
    // And print them
    log.info("This is just row3");
    printRow(rowOne);
    printRow(rowTwo);
    printRow(rowThree);
    System.out.flush();
    
    // Should only see rowThree
    
    // Always close your batchwriter
    
    bw.close();
    
    // and lets clean up our mess
    connector.tableOperations().delete(table);
    
    // fin~
    
  }
  
  /**
   * Deletes a row given a text object
   * 
   * @param row
   * @throws TableNotFoundException
   * @throws AccumuloSecurityException
   * @throws AccumuloException
   */
  private static void deleteRow(Text row) throws AccumuloException, AccumuloSecurityException, TableNotFoundException {
    deleteRow(getRow(row));
  }
  
  /**
   * Deletes a row, given a Scanner of JUST that row
   * 
   * @param scanner
   */
  private static void deleteRow(Scanner scanner) throws MutationsRejectedException {
    Mutation deleter = null;
    // iterate through the keys
    for (Entry entry : scanner) {
      // create a mutation for the row
      if (deleter == null)
        deleter = new Mutation(entry.getKey().getRow());
      // the remove function adds the key with the delete flag set to true
      deleter.putDelete(entry.getKey().getColumnFamily(), entry.getKey().getColumnQualifier());
    }
    bw.addMutation(deleter);
    bw.flush();
  }
  
  /**
   * Just a generic print function given an iterator. Not necessarily just for printing a single row
   * 
   * @param scanner
   */
  private static void printRow(Scanner scanner) {
    // iterates through and prints
    for (Entry entry : scanner)
      log.info("Key: " + entry.getKey().toString() + " Value: " + entry.getValue().toString());
  }
  
  /**
   * Gets a scanner over one row
   * 
   * @param row
   * @return
   * @throws TableNotFoundException
   * @throws AccumuloSecurityException
   * @throws AccumuloException
   * @throws IOException
   */
  private static Scanner getRow(Text row) throws AccumuloException, AccumuloSecurityException, TableNotFoundException {
    // Create a scanner
    Scanner scanner = connector.createScanner(table, Constants.NO_AUTHS);
    // Say start key is the one with key of row
    // and end key is the one that immediately follows the row
    scanner.setRange(new Range(row));
    return scanner;
  }
  
}