/// <summary>Given an output filename, write a bunch of random records to it.</summary>
/// <exception cref="System.IO.IOException"/>
/// <exception cref="System.Exception"/>
protected override void Map(Text key, Text value, Mapper.Context context)
{
int itemCount = 0;
while (numBytesToWrite > 0)
{
// Generate the key/value
int noWordsKey = minWordsInKey + (wordsInKeyRange != 0 ? random.Next(wordsInKeyRange
) : 0);
int noWordsValue = minWordsInValue + (wordsInValueRange != 0 ? random.Next(wordsInValueRange
) : 0);
Text keyWords = GenerateSentence(noWordsKey);
Text valueWords = GenerateSentence(noWordsValue);
// Write the sentence
context.Write(keyWords, valueWords);
numBytesToWrite -= (keyWords.GetLength() + valueWords.GetLength());
// Update counters, progress etc.
context.GetCounter(RandomTextWriter.Counters.BytesWritten).Increment(keyWords.GetLength
() + valueWords.GetLength());
context.GetCounter(RandomTextWriter.Counters.RecordsWritten).Increment(1);
if (++itemCount % 200 == 0)
{
context.SetStatus("wrote record " + itemCount + ". " + numBytesToWrite + " bytes left."
);
}
}
context.SetStatus("done with " + itemCount + " records.");
}
/// <summary>Given an output filename, write a bunch of random records to it.</summary>
/// <exception cref="System.IO.IOException"/>
/// <exception cref="System.Exception"/>
protected override void Map(WritableComparable key, Writable value, Mapper.Context
context)
{
int itemCount = 0;
while (numBytesToWrite > 0)
{
int keyLength = minKeySize + (keySizeRange != 0 ? random.Next(keySizeRange) : 0);
randomKey.SetSize(keyLength);
RandomizeBytes(randomKey.GetBytes(), 0, randomKey.GetLength());
int valueLength = minValueSize + (valueSizeRange != 0 ? random.Next(valueSizeRange
) : 0);
randomValue.SetSize(valueLength);
RandomizeBytes(randomValue.GetBytes(), 0, randomValue.GetLength());
context.Write(randomKey, randomValue);
numBytesToWrite -= keyLength + valueLength;
context.GetCounter(RandomWriter.Counters.BytesWritten).Increment(keyLength + valueLength
);
context.GetCounter(RandomWriter.Counters.RecordsWritten).Increment(1);
if (++itemCount % 200 == 0)
{
context.SetStatus("wrote record " + itemCount + ". " + numBytesToWrite + " bytes left."
);
}
}
context.SetStatus("done with " + itemCount + " records.");
}
/// <summary>Map method.</summary>
/// <param name="offset">samples starting from the (offset+1)th sample.</param>
/// <param name="size">the number of samples for this map</param>
/// <param name="context">output {ture->numInside, false->numOutside}</param>
/// <exception cref="System.IO.IOException"/>
/// <exception cref="System.Exception"/>
protected override void Map(LongWritable offset, LongWritable size, Mapper.Context
context)
{
QuasiMonteCarlo.HaltonSequence haltonsequence = new QuasiMonteCarlo.HaltonSequence
(offset.Get());
long numInside = 0L;
long numOutside = 0L;
for (long i = 0; i < size.Get();)
{
//generate points in a unit square
double[] point = haltonsequence.NextPoint();
//count points inside/outside of the inscribed circle of the square
double x = point[0] - 0.5;
double y = point[1] - 0.5;
if (x * x + y * y > 0.25)
{
numOutside++;
}
else
{
numInside++;
}
//report status
i++;
if (i % 1000 == 0)
{
context.SetStatus("Generated " + i + " samples.");
}
}
//output map results
context.Write(new BooleanWritable(true), new LongWritable(numInside));
context.Write(new BooleanWritable(false), new LongWritable(numOutside));
}
/// <exception cref="System.IO.IOException"/>
protected override void Map(LongWritable key, Text value, Mapper.Context context)
{
StringBuilder sb = new StringBuilder(512);
for (int i = 0; i < 1000; i++)
{
sb.Append("a");
}
context.SetStatus(sb.ToString());
int progressStatusLength = context.GetConfiguration().GetInt(MRConfig.ProgressStatusLenLimitKey
, MRConfig.ProgressStatusLenLimitDefault);
if (context.GetStatus().Length > progressStatusLength)
{
throw new IOException("Status is not truncated");
}
}