Example usage for java.util Collections singletonList

Introduction

In this page you can find the example usage for java.util Collections singletonList.

Prototype

public static <T> List<T> singletonList(T o) 

Source Link

Document

Returns an immutable list containing only the specified object.

Usage

From source file:com.twentyn.patentSearch.DocumentSearch.java

public static void main(String[] args) throws Exception {
    System.out.println("Starting up...");
    System.out.flush();/*w  ww  . j ava2s.  com*/
    Options opts = new Options();
    opts.addOption(Option.builder("x").longOpt("index").hasArg().required().desc("Path to index file to read")
            .build());
    opts.addOption(Option.builder("h").longOpt("help").desc("Print this help message and exit").build());
    opts.addOption(Option.builder("v").longOpt("verbose").desc("Print verbose log output").build());

    opts.addOption(Option.builder("f").longOpt("field").hasArg().desc("The indexed field to search").build());
    opts.addOption(
            Option.builder("q").longOpt("query").hasArg().desc("The query to use when searching").build());
    opts.addOption(Option.builder("l").longOpt("list-file").hasArg()
            .desc("A file containing a list of queries to run in sequence").build());
    opts.addOption(
            Option.builder("e").longOpt("enumerate").desc("Enumerate the documents in the index").build());
    opts.addOption(Option.builder("d").longOpt("dump").hasArg()
            .desc("Dump terms in the document index for a specified field").build());
    opts.addOption(
            Option.builder("o").longOpt("output").hasArg().desc("Write results JSON to this file.").build());
    opts.addOption(Option.builder("n").longOpt("inchi-field").hasArg()
            .desc("The index of the InChI field if an input TSV is specified.").build());
    opts.addOption(Option.builder("s").longOpt("synonym-field").hasArg()
            .desc("The index of the chemical synonym field if an input TSV is specified.").build());

    HelpFormatter helpFormatter = new HelpFormatter();
    CommandLineParser cmdLineParser = new DefaultParser();
    CommandLine cmdLine = null;
    try {
        cmdLine = cmdLineParser.parse(opts, args);
    } catch (ParseException e) {
        System.out.println("Caught exception when parsing command line: " + e.getMessage());
        helpFormatter.printHelp("DocumentIndexer", opts);
        System.exit(1);
    }

    if (cmdLine.hasOption("help")) {
        helpFormatter.printHelp("DocumentIndexer", opts);
        System.exit(0);
    }

    if (!(cmdLine.hasOption("enumerate") || cmdLine.hasOption("dump") || (cmdLine.hasOption("field")
            && (cmdLine.hasOption("query") || cmdLine.hasOption("list-file"))))) {
        System.out.println("Must specify one of 'enumerate', 'dump', or 'field' + {'query', 'list-file'}");
        helpFormatter.printHelp("DocumentIndexer", opts);
        System.exit(1);
    }

    if (cmdLine.hasOption("verbose")) {
        // With help from http://stackoverflow.com/questions/23434252/programmatically-change-log-level-in-log4j2
        LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
        Configuration ctxConfig = ctx.getConfiguration();
        LoggerConfig logConfig = ctxConfig.getLoggerConfig(LogManager.ROOT_LOGGER_NAME);
        logConfig.setLevel(Level.DEBUG);

        ctx.updateLoggers();
        LOGGER.debug("Verbose logging enabled");
    }

    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.enable(SerializationFeature.INDENT_OUTPUT);
    objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);

    LOGGER.info("Opening index at " + cmdLine.getOptionValue("index"));

    try (Directory indexDir = FSDirectory.open(new File(cmdLine.getOptionValue("index")).toPath());
            IndexReader indexReader = DirectoryReader.open(indexDir);) {
        if (cmdLine.hasOption("enumerate")) {
            /* Enumerate all documents in the index.
             * With help from
             * http://stackoverflow.com/questions/2311845/is-it-possible-to-iterate-through-documents-stored-in-lucene-index
             */
            for (int i = 0; i < indexReader.maxDoc(); i++) {
                Document doc = indexReader.document(i);
                LOGGER.info("Doc " + i + ":");
                LOGGER.info(doc);
            }
        } else if (cmdLine.hasOption("dump")) {
            /* Dump indexed terms for a specific field.
             * With help from http://stackoverflow.com/questions/11148036/find-list-of-terms-indexed-by-lucene */
            Terms terms = SlowCompositeReaderWrapper.wrap(indexReader).terms(cmdLine.getOptionValue("dump"));
            LOGGER.info("Has positions: " + terms.hasPositions());
            LOGGER.info("Has offsets:   " + terms.hasOffsets());
            LOGGER.info("Has freqs:     " + terms.hasFreqs());
            LOGGER.info("Stats:         " + terms.getStats());
            LOGGER.info(terms);
            TermsEnum termsEnum = terms.iterator();
            BytesRef br = null;
            while ((br = termsEnum.next()) != null) {
                LOGGER.info("  " + br.utf8ToString());
            }

        } else {
            IndexSearcher searcher = new IndexSearcher(indexReader);
            String field = cmdLine.getOptionValue("field");

            List<Pair<String, String>> queries = null;
            if (cmdLine.hasOption("query")) {
                queries = Collections.singletonList(Pair.of("", cmdLine.getOptionValue("query")));
            } else if (cmdLine.hasOption("list-file")) {
                if (!(cmdLine.hasOption("inchi-field") && cmdLine.hasOption("synonym-field"))) {
                    LOGGER.error("Must specify both inchi-field and synonym-field when using list-file.");
                    System.exit(1);
                }
                Integer inchiField = Integer.parseInt(cmdLine.getOptionValue("inchi-field"));
                Integer synonymField = Integer.parseInt(cmdLine.getOptionValue("synonym-field"));

                queries = new LinkedList<>();
                BufferedReader r = new BufferedReader(new FileReader(cmdLine.getOptionValue("list-file")));
                String line;
                while ((line = r.readLine()) != null) {
                    line = line.trim();
                    if (!line.isEmpty()) {
                        // TODO: use a proper TSV reader; this is intentionally terrible as is.
                        String[] fields = line.split("\t");
                        queries.add(Pair.of(fields[inchiField].replace("\"", ""), fields[synonymField]));
                    }
                }
                r.close();
            }

            if (queries == null || queries.size() == 0) {
                LOGGER.error("Found no queries to run.");
                return;
            }

            List<SearchResult> searchResults = new ArrayList<>(queries.size());
            for (Pair<String, String> queryPair : queries) {
                String inchi = queryPair.getLeft();
                String rawQueryString = queryPair.getRight();
                /* The Lucene query parser interprets the kind of structural annotations we see in chemical entities
                 * as query directives, which is not what we want at all.  Phrase queries seem to work adequately
                 * with the analyzer we're currently using. */
                String queryString = rawQueryString.trim().toLowerCase();
                String[] parts = queryString.split("\\s+");
                PhraseQuery query = new PhraseQuery();
                for (String p : parts) {
                    query.add(new Term(field, p));
                }
                LOGGER.info("Running query: " + query.toString());

                BooleanQuery bq = new BooleanQuery();
                bq.add(query, BooleanClause.Occur.MUST);
                bq.add(new TermQuery(new Term(field, "yeast")), BooleanClause.Occur.SHOULD);
                bq.add(new TermQuery(new Term(field, "ferment")), BooleanClause.Occur.SHOULD);
                bq.add(new TermQuery(new Term(field, "fermentation")), BooleanClause.Occur.SHOULD);
                bq.add(new TermQuery(new Term(field, "fermentive")), BooleanClause.Occur.SHOULD);
                bq.add(new TermQuery(new Term(field, "saccharomyces")), BooleanClause.Occur.SHOULD);

                LOGGER.info("  Full query: " + bq.toString());

                TopDocs topDocs = searcher.search(bq, 100);
                ScoreDoc[] scoreDocs = topDocs.scoreDocs;
                if (scoreDocs.length == 0) {
                    LOGGER.info("Search returned no results.");
                }
                List<ResultDocument> results = new ArrayList<>(scoreDocs.length);
                for (int i = 0; i < scoreDocs.length; i++) {
                    ScoreDoc scoreDoc = scoreDocs[i];
                    Document doc = indexReader.document(scoreDoc.doc);
                    LOGGER.info("Doc " + i + ": " + scoreDoc.doc + ", score " + scoreDoc.score + ": "
                            + doc.get("id") + ", " + doc.get("title"));
                    results.add(new ResultDocument(scoreDoc.doc, scoreDoc.score, doc.get("title"),
                            doc.get("id"), null));
                }
                LOGGER.info("----- Done with query " + query.toString());
                // TODO: reduce memory usage when not writing results to an output file.
                searchResults.add(new SearchResult(inchi, rawQueryString, bq, results));
            }

            if (cmdLine.hasOption("output")) {
                try (FileWriter writer = new FileWriter(cmdLine.getOptionValue("output"));) {
                    writer.write(objectMapper.writeValueAsString(searchResults));
                }
            }
        }
    }
}

---

From source file:Main.java

public static <T> List<T> readOnlyCopy(List<T> orig) {
    if (orig.isEmpty())
        return Collections.emptyList();
    if (orig.size() == 1)
        return Collections.singletonList(orig.get(0));
    ArrayList<T> copy = new ArrayList<>(orig.size());
    copy.addAll(orig);/*from   w  w  w  .j a  v  a 2  s .  c o  m*/
    return Collections.unmodifiableList(copy);
}

---

From source file:Main.java

public static List<?> toList(Object obj) {
    if (obj instanceof List) {
        return (List<?>) obj;
    } else if (obj == null) {
        return Collections.emptyList();
    } else {//from w w w .  j  a  v a2  s  .com
        return Collections.singletonList(obj);
    }
}

---

From source file:Main.java

public static <T> List<List<T>> partition(List<T> inputList, int size) {
    if (inputList.size() == 0) {
        return Collections.singletonList(inputList);
    }/*from  w w w. j  a  va 2s .  c o  m*/

    int partitions = inputList.size() / size + (inputList.size() % size > 0 ? 1 : 0);

    List<List<T>> result = new ArrayList<List<T>>(partitions);

    for (int i = 0; i < partitions - 1; i++) {
        result.add(inputList.subList(i * size, (i + 1) * size));
    }

    result.add(inputList.subList((partitions - 1) * size, inputList.size()));

    return result;
}

---

From source file:Main.java

public static <T> List<T> toImmutableList(List<T> list) {
    switch (list.size()) {
    case 0:/*from  w ww .j a  v a 2  s .c om*/
        return Collections.emptyList();
    case 1:
        return Collections.singletonList(list.get(0));
    default:
        return Collections.unmodifiableList(list);
    }
}

---

From source file:Main.java

public static List<String> split(String str, char delimiter) {

    if (TextUtils.isEmpty(str)) {
        return Collections.emptyList();
    }//from w  w  w  . j  a v  a 2s.  com

    int substringsCount = 1;
    for (int i = 0, len = str.length(); i < len; i++) {
        if (str.charAt(i) == delimiter) {
            substringsCount++;
        }
    }

    if (substringsCount == 1) {
        return Collections.singletonList(str);
    }

    List<String> split = new ArrayList<String>(substringsCount);

    int index = str.indexOf(delimiter);
    int lastIndex = 0;
    while (index != -1) {

        split.add(str.substring(lastIndex, index));

        lastIndex = index + 1;
        index = str.indexOf(delimiter, lastIndex);
    }

    split.add(str.substring(lastIndex, str.length())); // add the final string after the last delimiter

    return split;
}

---

From source file:Main.java

public static <T> List<T> list(T t) {
    return Collections.singletonList(t);
}

---

From source file:Main.java

/**
 * Returns a collection with fast contains() implementation. The collection
 * is intended to be reusable, a single use will not be efficient. Most
 * efficient with primitive objects (String, Integer...)
 *///from   w w  w .j ava 2  s.c om
@SuppressWarnings("unchecked")
public static <T> Collection<T> fastSearchCollection(T... arr) {
    final int size = arr.length;
    if (size == 0)
        return Collections.EMPTY_LIST;

    if (size == 1)
        Collections.singletonList(arr[0]);

    // optimization for short list, avoid hash
    if (size <= 8) {
        return Arrays.asList(arr);
    }
    // big lists, use hash (constant time)
    return new HashSet<T>(Arrays.asList(arr));
}

---

From source file:Main.java

public static <T> List<T> list(final T... entries) {
    switch (entries.length) {
    case 0: {/*from   w ww . ja  v a  2 s  . c o  m*/
        return Collections.emptyList();
    }
    case 1: {
        return Collections.singletonList(entries[0]);
    }
    default: {
        final List<T> result = new ArrayList<T>();

        for (T entry : entries) {
            result.add(entry);
        }

        return result;
    }
    }
}

---

From source file:Main.java

@SuppressLint("NewApi")
private static List<Camera.Area> buildMiddleArea(int areaPer1000) {
    return Collections
            .singletonList(new Camera.Area(new Rect(-areaPer1000, -areaPer1000, areaPer1000, areaPer1000), 1));
}

---

• «
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31
• 32
• 33
• 34
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• 45
• 46
• 47
• 48
• 49
• 50
• »