/**
* Optimization hook. Override this to make SequenceFile.Sorter's scream.
*
* <p>The default implementation reads the data into two {@link WritableComparable}s (using {@link
* Writable#readFields(DataInput)}, then calls {@link
* #compare(WritableComparable,WritableComparable)}.
*/
public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
try {
buffer.reset(b1, s1, l1); // parse key1
key1.readFields(buffer);
buffer.reset(b2, s2, l2); // parse key2
key2.readFields(buffer);
} catch (IOException e) {
throw new RuntimeException(e);
}
return compare(key1, key2); // compare them
}
/** Utility method for testing writables. */
public static Writable testWritable(Writable before, Configuration conf) throws Exception {
DataOutputBuffer dob = new DataOutputBuffer();
before.write(dob);
DataInputBuffer dib = new DataInputBuffer();
dib.reset(dob.getData(), dob.getLength());
Writable after = (Writable) ReflectionUtils.newInstance(before.getClass(), conf);
after.readFields(dib);
assertEquals(before, after);
return after;
}
/** Used by child copy constructors. */
protected synchronized void copy(Writable other) {
if (other != null) {
try {
DataOutputBuffer out = new DataOutputBuffer();
other.write(out);
DataInputBuffer in = new DataInputBuffer();
in.reset(out.getData(), out.getLength());
readFields(in);
} catch (IOException e) {
throw new IllegalArgumentException("map cannot be copied: " + e.getMessage());
}
} else {
throw new IllegalArgumentException("source map cannot be null");
}
}
/** Move the data from the output buffer to the input buffer. */
void moveData() {
inBuffer.reset(outBuffer.getData(), outBuffer.getLength());
}