[
https://issues.apache.org/jira/browse/OPENNLP-1539?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17849016#comment-17849016
]
ASF GitHub Bot commented on OPENNLP-1539:
-----------------------------------------
rzo1 commented on code in PR #601:
URL: https://github.com/apache/opennlp/pull/601#discussion_r1611936275
##########
opennlp-tools/src/main/java/opennlp/tools/postag/POSTagFormatMapper.java:
##########
@@ -0,0 +1,207 @@
+/*
+ * 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 opennlp.tools.postag;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A mapping implementation for converting between different POS tag formats.
+ * This class supports conversion between Penn Treebank (PENN) and Universal
Dependencies (UD) formats.
+ * The conversion is based on the <a
href="https://universaldependencies.org/tagset-conversion/en-penn-uposf.html";>Universal
Dependencies conversion table.</a>
+ * Please note that when converting from UD to Penn format, there may be
ambiguity in some cases.
+ */
+public class POSTagFormatMapper {
+
+ private static final Logger logger =
LoggerFactory.getLogger(POSTagFormatMapper.class);
+
+ private static final Map<String, String> CONVERSION_TABLE_PENN_TO_UD = new
HashMap<>();
+ private static final Map<String, String> CONVERSION_TABLE_UD_TO_PENN = new
HashMap<>();
+
+ static {
+ /*
+ * This is a conversion table to convert PENN to UD format as described in
+ * https://universaldependencies.org/tagset-conversion/en-penn-uposf.html
+ */
+ CONVERSION_TABLE_PENN_TO_UD.put("#", "SYM");
+ CONVERSION_TABLE_PENN_TO_UD.put("$", "SYM");
+ CONVERSION_TABLE_PENN_TO_UD.put("''", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put(",", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put("-LRB-", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put("-RRB-", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put(".", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put(":", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put("AFX", "ADJ");
+ CONVERSION_TABLE_PENN_TO_UD.put("CC", "CCONJ");
+ CONVERSION_TABLE_PENN_TO_UD.put("CD", "NUM");
+ CONVERSION_TABLE_PENN_TO_UD.put("DT", "DET");
+ CONVERSION_TABLE_PENN_TO_UD.put("EX", "PRON");
+ CONVERSION_TABLE_PENN_TO_UD.put("FW", "X");
+ CONVERSION_TABLE_PENN_TO_UD.put("HYPH", "PUNCT");
+ CONVERSION_TABLE_PENN_TO_UD.put("IN", "ADP");
+ CONVERSION_TABLE_PENN_TO_UD.put("JJ", "ADJ");
+ CONVERSION_TABLE_PENN_TO_UD.put("JJR", "ADJ");
+ CONVERSION_TABLE_PENN_TO_UD.put("JJS", "ADJ");
+ CONVERSION_TABLE_PENN_TO_UD.put("LS", "X");
+ CONVERSION_TABLE_PENN_TO_UD.put("MD", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("NIL", "X");
+ CONVERSION_TABLE_PENN_TO_UD.put("NN", "NOUN");
+ CONVERSION_TABLE_PENN_TO_UD.put("NNP", "PROPN");
+ CONVERSION_TABLE_PENN_TO_UD.put("NNPS", "PROPN");
+ CONVERSION_TABLE_PENN_TO_UD.put("NNS", "NOUN");
+ CONVERSION_TABLE_PENN_TO_UD.put("PDT", "DET");
+ CONVERSION_TABLE_PENN_TO_UD.put("POS", "PART");
+ CONVERSION_TABLE_PENN_TO_UD.put("PRP", "PRON");
+ CONVERSION_TABLE_PENN_TO_UD.put("PRP$", "DET");
+ CONVERSION_TABLE_PENN_TO_UD.put("RB", "ADV");
+ CONVERSION_TABLE_PENN_TO_UD.put("RBR", "ADV");
+ CONVERSION_TABLE_PENN_TO_UD.put("RBS", "ADV");
+ CONVERSION_TABLE_PENN_TO_UD.put("RP", "ADP");
+ CONVERSION_TABLE_PENN_TO_UD.put("SYM", "SYM");
+ CONVERSION_TABLE_PENN_TO_UD.put("TO", "PART");
+ CONVERSION_TABLE_PENN_TO_UD.put("UH", "INTJ");
+ CONVERSION_TABLE_PENN_TO_UD.put("VB", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("VBD", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("VBG", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("VBN", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("VBP", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("VBZ", "VERB");
+ CONVERSION_TABLE_PENN_TO_UD.put("WDT", "DET");
+ CONVERSION_TABLE_PENN_TO_UD.put("WP", "PRON");
+ CONVERSION_TABLE_PENN_TO_UD.put("WP$", "DET");
+ CONVERSION_TABLE_PENN_TO_UD.put("WRB", "ADV");
+
+ /*
+ * Note: The back conversion might lose information.
+ */
+ CONVERSION_TABLE_UD_TO_PENN.put("ADJ", "JJ");
+ CONVERSION_TABLE_UD_TO_PENN.put("ADP", "IN");
+ CONVERSION_TABLE_UD_TO_PENN.put("ADV", "RB");
+ CONVERSION_TABLE_UD_TO_PENN.put("AUX", "MD");
+ CONVERSION_TABLE_UD_TO_PENN.put("CCONJ", "CC");
+ CONVERSION_TABLE_UD_TO_PENN.put("DET", "DT");
+ CONVERSION_TABLE_UD_TO_PENN.put("INTJ", "UH");
+ CONVERSION_TABLE_UD_TO_PENN.put("NOUN", "NN");
+ CONVERSION_TABLE_UD_TO_PENN.put("NUM", "CD");
+ CONVERSION_TABLE_UD_TO_PENN.put("PART", "RP");
+ CONVERSION_TABLE_UD_TO_PENN.put("PRON", "PRP");
+ CONVERSION_TABLE_UD_TO_PENN.put("PROPN", "NNP");
+ CONVERSION_TABLE_UD_TO_PENN.put("PUNCT", ".");
+ CONVERSION_TABLE_UD_TO_PENN.put("SCONJ", "IN");
+ CONVERSION_TABLE_UD_TO_PENN.put("SYM", "SYM");
+ CONVERSION_TABLE_UD_TO_PENN.put("VERB", "VB");
+ CONVERSION_TABLE_UD_TO_PENN.put("X", "FW");
+ }
+
+ private final POSTagFormat modelFormat;
+
+ protected POSTagFormatMapper(final String[] possibleOutcomes) {
+ Objects.requireNonNull(possibleOutcomes, "Outcomes must not be NULL.");
+ this.modelFormat = guessModelTagFormat(possibleOutcomes);
Review Comment:
Do we have a chance to get it from the POSModel itself? Otherwise, we only
have the outcomes to decide and need to guess?
> Introduce parameter for POSTaggerME to configure output POS tag format
> ----------------------------------------------------------------------
>
> Key: OPENNLP-1539
> URL: https://issues.apache.org/jira/browse/OPENNLP-1539
> Project: OpenNLP
> Issue Type: Improvement
> Components: POS Tagger
> Affects Versions: 2.0.0, 2.1.0, 2.2.0, 2.3.0
> Reporter: Martin Wiesner
> Assignee: Richard Zowalla
> Priority: Major
> Fix For: 2.4.0
>
>
> [Classic (legacy) POS models|https://opennlp.sourceforge.net/models-1.5/]
> output tags in the [PENN Treebank POS
> tag|https://www.ling.upenn.edu/courses/Fall_2003/ling001/penn_treebank_pos.html]
> format.
> The modern UD-based models, however, differ in the [longer output
> format|https://universaldependencies.org/u/pos/], e.g. "VB" (Penn) vs. "VERB"
> (UD). Extended (UD) word features are covered here:
> https://universaldependencies.org/u/feat/index.html
> This difference results in mismatches and will cause existing IT / tests to
> fail, if executed. Luckily, a mapping table is found here:
> https://universaldependencies.org/tagset-conversion/en-penn-uposf.html
> To provide compatibility for existing applications and/or use-cases, we need
> to provide a way to retrieve both POS formats.
> Aims:
> - Introduce a constructor parameter for POSTaggerME to configure tag format /
> style: Penn or UD style
> - Implement a mapping between both POS tag formats: UD <==> Penn
> - Update the OpenNLP Manual to explain differences of POS tag format and
> configuration parameter
> Conceptual idea:
> - {{new POSTaggerME("en")}} => by _default_: UD format "as is"
> - {{new POSTaggerME("en", POSTagFormat.PENN)}} => by _intention_, here: Penn
> style
> Benefit:
> 1. It should be explicit so devs / user see what they will get via
> {{POSTagFormat}}. Enum values: POSTagFormat.UD, POSTagFormat.PENN,
> POSTagFormat.DEFAULT
> 2. IT tests can now be formulated to work on both modern and legacy models.
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