org.egothor.stemmer.Optimizer Maven / Gradle / Ivy
/*
Egothor Software License version 1.00
Copyright (C) 1997-2004 Leo Galambos.
Copyright (C) 2002-2004 "Egothor developers"
on behalf of the Egothor Project.
All rights reserved.
This software is copyrighted by the "Egothor developers". If this
license applies to a single file or document, the "Egothor developers"
are the people or entities mentioned as copyright holders in that file
or document. If this license applies to the Egothor project as a
whole, the copyright holders are the people or entities mentioned in
the file CREDITS. This file can be found in the same location as this
license in the distribution.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright
notice, the list of contributors, this list of conditions, and the
following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, the list of contributors, this list of conditions, and the
disclaimer that follows these conditions in the documentation
and/or other materials provided with the distribution.
3. The name "Egothor" must not be used to endorse or promote products
derived from this software without prior written permission. For
written permission, please contact [email protected]
4. Products derived from this software may not be called "Egothor",
nor may "Egothor" appear in their name, without prior written
permission from [email protected].
In addition, we request that you include in the end-user documentation
provided with the redistribution and/or in the software itself an
acknowledgement equivalent to the following:
"This product includes software developed by the Egothor Project.
http://egothor.sf.net/"
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE EGOTHOR PROJECT OR ITS CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This software consists of voluntary contributions made by many
individuals on behalf of the Egothor Project and was originally
created by Leo Galambos ([email protected]).
*/
package org.egothor.stemmer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import org.apache.lucene.internal.hppc.CharCursor;
/**
* The Optimizer class is a Trie that will be reduced (have empty rows removed).
*
* The reduction will be made by joining two rows where the first is a subset of the second.
*/
public class Optimizer extends Reduce {
/** Constructor for the Optimizer object. */
public Optimizer() {}
/**
* Optimize (remove empty rows) from the given Trie and return the resulting Trie.
*
* @param orig the Trie to consolidate
* @return the newly consolidated Trie
*/
@Override
public Trie optimize(Trie orig) {
List cmds = orig.cmds;
List rows = new ArrayList<>();
List orows = orig.rows;
int[] remap = new int[orows.size()];
for (int j = orows.size() - 1; j >= 0; j--) {
Row now = new Remap(orows.get(j), remap);
boolean merged = false;
for (int i = 0; i < rows.size(); i++) {
Row q = merge(now, rows.get(i));
if (q != null) {
rows.set(i, q);
merged = true;
remap[j] = i;
break;
}
}
if (merged == false) {
remap[j] = rows.size();
rows.add(now);
}
}
int root = remap[orig.root];
Arrays.fill(remap, -1);
rows = removeGaps(root, rows, new ArrayList(), remap);
return new Trie(orig.forward, remap[root], cmds, rows);
}
/**
* Merge the given rows and return the resulting Row.
*
* @param master the master Row
* @param existing the existing Row
* @return the resulting Row, or null if the operation cannot be realized
*/
public Row merge(Row master, Row existing) {
Iterator i = master.cells.keys().iterator();
Row n = new Row();
for (; i.hasNext(); ) {
char ch = i.next().value;
// XXX also must handle Cnt and Skip !!
Cell a = master.cells.get(ch);
Cell b = existing.cells.get(ch);
Cell s = (b == null) ? new Cell(a) : merge(a, b);
if (s == null) {
return null;
}
n.cells.put(ch, s);
}
i = existing.cells.keys().iterator();
for (; i.hasNext(); ) {
char ch = i.next().value;
if (master.at(ch) != null) {
continue;
}
n.cells.put(ch, existing.at(ch));
}
return n;
}
/**
* Merge the given Cells and return the resulting Cell.
*
* @param m the master Cell
* @param e the existing Cell
* @return the resulting Cell, or null if the operation cannot be realized
*/
public Cell merge(Cell m, Cell e) {
Cell n = new Cell();
if (m.skip != e.skip) {
return null;
}
if (m.cmd >= 0) {
if (e.cmd >= 0) {
if (m.cmd == e.cmd) {
n.cmd = m.cmd;
} else {
return null;
}
} else {
n.cmd = m.cmd;
}
} else {
n.cmd = e.cmd;
}
if (m.ref >= 0) {
if (e.ref >= 0) {
if (m.ref == e.ref) {
if (m.skip == e.skip) {
n.ref = m.ref;
} else {
return null;
}
} else {
return null;
}
} else {
n.ref = m.ref;
}
} else {
n.ref = e.ref;
}
n.cnt = m.cnt + e.cnt;
n.skip = m.skip;
return n;
}
}