/* Copyright (C) 2003 Univ. of Massachusetts Amherst, Computer Science Dept.
This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
http://www.cs.umass.edu/~mccallum/mallet
This software is provided under the terms of the Common Public License,
version 1.0, as published by http://www.opensource.org. For further
information, see the file `LICENSE' included with this distribution. */
package cc.mallet.pipe;
import cc.mallet.pipe.Pipe;
import cc.mallet.pipe.SerialPipes;
import cc.mallet.types.Alphabet;
/**
* Created: Aug 28, 2005
*
* @author <A HREF="mailto:casutton@cs.umass.edu>casutton@cs.umass.edu</A>
* @version $Id: PipeUtils.java,v 1.1 2007/10/22 21:37:39 mccallum Exp $
*/
public class PipeUtils {
private PipeUtils () {}; // no instances
public static Pipe concatenatePipes (Pipe p1, Pipe p2)
{
Alphabet dataDict = combinedDataDicts (p1, p2);
Alphabet targetDict = combinedTargetDicts (p1, p2);
Pipe ret = new SerialPipes (new Pipe[] { p1, p2 });
if (dataDict != null) ret.dataAlphabetResolved = true;
if (targetDict != null) ret.targetAlphabetResolved = true;
ret.dataAlphabet = dataDict;
ret.targetAlphabet = targetDict;
return ret;
}
private static Alphabet combinedDataDicts (Pipe p1, Pipe p2)
{
if (p1.dataAlphabet == null) return p2.dataAlphabet;
if (p2.dataAlphabet == null) return p1.dataAlphabet;
if (p1.dataAlphabet == p2.dataAlphabet) return p2.dataAlphabet;
throw new IllegalArgumentException ("Attempt to concat pipes with incompatible data dicts.");
}
private static Alphabet combinedTargetDicts (Pipe p1, Pipe p2)
{
if (p1.targetAlphabet == null) return p2.targetAlphabet;
if (p2.targetAlphabet == null) return p1.targetAlphabet;
if (p1.targetAlphabet == p2.targetAlphabet) return p2.targetAlphabet;
throw new IllegalArgumentException ("Attempt to concat pipes with incompatible target dicts.");
}
}