org.apache.lucene.search.suggest.jaspell.JaspellLookup Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.search.suggest.jaspell;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import org.apache.lucene.search.suggest.InputIterator;
import org.apache.lucene.search.suggest.Lookup;
import org.apache.lucene.search.suggest.jaspell.JaspellTernarySearchTrie.TSTNode;
import org.apache.lucene.store.DataInput;
import org.apache.lucene.store.DataOutput;
import org.apache.lucene.util.Accountable;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.CharsRef;
import org.apache.lucene.util.CharsRefBuilder;
/**
* Suggest implementation based on
* JaSpell.
*
* @see JaspellTernarySearchTrie
* @deprecated Migrate to one of the newer suggesters which are much more RAM efficient.
*/
@Deprecated
public class JaspellLookup extends Lookup implements Accountable {
JaspellTernarySearchTrie trie = new JaspellTernarySearchTrie();
private boolean usePrefix = true;
private int editDistance = 2;
/** Number of entries the lookup was built with */
private long count = 0;
/**
* Creates a new empty trie
* @see #build(InputIterator)
* */
public JaspellLookup() {}
@Override
public void build(InputIterator iterator) throws IOException {
if (iterator.hasPayloads()) {
throw new IllegalArgumentException("this suggester doesn't support payloads");
}
if (iterator.hasContexts()) {
throw new IllegalArgumentException("this suggester doesn't support contexts");
}
count = 0;
trie = new JaspellTernarySearchTrie();
trie.setMatchAlmostDiff(editDistance);
BytesRef spare;
final CharsRefBuilder charsSpare = new CharsRefBuilder();
while ((spare = iterator.next()) != null) {
final long weight = iterator.weight();
if (spare.length == 0) {
continue;
}
charsSpare.copyUTF8Bytes(spare);
trie.put(charsSpare.toString(), Long.valueOf(weight));
count++;
}
}
/**
* Adds a new node if key already exists,
* otherwise replaces its value.
*
* This method always returns false.
*/
public boolean add(CharSequence key, Object value) {
trie.put(key, value);
// XXX
return false;
}
/**
* Returns the value for the specified key, or null
* if the key does not exist.
*/
public Object get(CharSequence key) {
return trie.get(key);
}
@Override
public List lookup(CharSequence key, Set contexts, boolean onlyMorePopular, int num) {
if (contexts != null) {
throw new IllegalArgumentException("this suggester doesn't support contexts");
}
List res = new ArrayList<>();
List list;
int count = onlyMorePopular ? num * 2 : num;
if (usePrefix) {
list = trie.matchPrefix(key, count);
} else {
list = trie.matchAlmost(key, count);
}
if (list == null || list.size() == 0) {
return res;
}
int maxCnt = Math.min(num, list.size());
if (onlyMorePopular) {
LookupPriorityQueue queue = new LookupPriorityQueue(num);
for (String s : list) {
long freq = ((Number)trie.get(s)).longValue();
queue.insertWithOverflow(new LookupResult(new CharsRef(s), freq));
}
for (LookupResult lr : queue.getResults()) {
res.add(lr);
}
} else {
for (int i = 0; i < maxCnt; i++) {
String s = list.get(i);
long freq = ((Number)trie.get(s)).longValue();
res.add(new LookupResult(new CharsRef(s), freq));
}
}
return res;
}
private static final byte LO_KID = 0x01;
private static final byte EQ_KID = 0x02;
private static final byte HI_KID = 0x04;
private static final byte HAS_VALUE = 0x08;
private void readRecursively(DataInput in, TSTNode node) throws IOException {
node.splitchar = in.readString().charAt(0);
byte mask = in.readByte();
if ((mask & HAS_VALUE) != 0) {
node.data = Long.valueOf(in.readLong());
}
if ((mask & LO_KID) != 0) {
TSTNode kid = new TSTNode('\0', node);
node.relatives[TSTNode.LOKID] = kid;
readRecursively(in, kid);
}
if ((mask & EQ_KID) != 0) {
TSTNode kid = new TSTNode('\0', node);
node.relatives[TSTNode.EQKID] = kid;
readRecursively(in, kid);
}
if ((mask & HI_KID) != 0) {
TSTNode kid = new TSTNode('\0', node);
node.relatives[TSTNode.HIKID] = kid;
readRecursively(in, kid);
}
}
private void writeRecursively(DataOutput out, TSTNode node) throws IOException {
if (node == null) {
return;
}
out.writeString(new String(new char[] {node.splitchar}, 0, 1));
byte mask = 0;
if (node.relatives[TSTNode.LOKID] != null) mask |= LO_KID;
if (node.relatives[TSTNode.EQKID] != null) mask |= EQ_KID;
if (node.relatives[TSTNode.HIKID] != null) mask |= HI_KID;
if (node.data != null) mask |= HAS_VALUE;
out.writeByte(mask);
if (node.data != null) {
out.writeLong(((Number)node.data).longValue());
}
writeRecursively(out, node.relatives[TSTNode.LOKID]);
writeRecursively(out, node.relatives[TSTNode.EQKID]);
writeRecursively(out, node.relatives[TSTNode.HIKID]);
}
@Override
public boolean store(DataOutput output) throws IOException {
output.writeVLong(count);
TSTNode root = trie.getRoot();
if (root == null) { // empty tree
return false;
}
writeRecursively(output, root);
return true;
}
@Override
public boolean load(DataInput input) throws IOException {
count = input.readVLong();
TSTNode root = new TSTNode('\0', null);
readRecursively(input, root);
trie.setRoot(root);
return true;
}
@Override
public long ramBytesUsed() {
return trie.ramBytesUsed();
}
@Override
public long getCount() {
return count;
}
}