/// <summary>
/// Returns final FST. NOTE: this will return null if
/// nothing is accepted by the FST.
/// </summary>
public virtual FST <T> Finish()
{
UnCompiledNode <T> root = frontier[0];
// minimize nodes in the last word's suffix
DoFreezeTail(0);
if (root.InputCount < minSuffixCount1 || root.InputCount < minSuffixCount2 || root.NumArcs == 0)
{
if (fst.emptyOutput == null)
{
return(null);
}
else if (minSuffixCount1 > 0 || minSuffixCount2 > 0)
{
// empty string got pruned
return(null);
}
}
else
{
if (minSuffixCount2 != 0)
{
CompileAllTargets(root, lastInput.Length);
}
}
//if (DEBUG) System.out.println(" builder.finish root.isFinal=" + root.isFinal + " root.Output=" + root.Output);
fst.Finish(CompileNode(root, lastInput.Length).Node);
if (doPackFST)
{
return(fst.Pack(3, Math.Max(10, (int)(fst.NodeCount / 4)), acceptableOverheadRatio));
}
else
{
return(fst);
}
}