Example usage for java.util Collections singleton

Introduction

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

Prototype

public static <T> Set<T> singleton(T o)

Source Link

Document

Returns an immutable set containing only the specified object.

Usage

From source file:com.tamingtext.tagging.LuceneTagExtractor.java

public static void main(String[] args) throws IOException {
    DefaultOptionBuilder obuilder = new DefaultOptionBuilder();
    ArgumentBuilder abuilder = new ArgumentBuilder();
    GroupBuilder gbuilder = new GroupBuilder();

    Option inputOpt = obuilder.withLongName("dir").withRequired(true)
            .withArgument(abuilder.withName("dir").withMinimum(1).withMaximum(1).create())
            .withDescription("The Lucene directory").withShortName("d").create();

    Option outputOpt = obuilder.withLongName("output").withRequired(false)
            .withArgument(abuilder.withName("output").withMinimum(1).withMaximum(1).create())
            .withDescription("The output directory").withShortName("o").create();

    Option maxOpt = obuilder.withLongName("max").withRequired(false)
            .withArgument(abuilder.withName("max").withMinimum(1).withMaximum(1).create())
            .withDescription(/* w  ww  .j a v  a 2 s. c  o m*/
                    "The maximum number of vectors to output.  If not specified, then it will loop over all docs")
            .withShortName("m").create();

    Option fieldOpt = obuilder.withLongName("field").withRequired(true)
            .withArgument(abuilder.withName("field").withMinimum(1).withMaximum(1).create())
            .withDescription("The field in the index").withShortName("f").create();

    Option helpOpt = obuilder.withLongName("help").withDescription("Print out help").withShortName("h")
            .create();

    Group group = gbuilder.withName("Options").withOption(inputOpt).withOption(outputOpt).withOption(maxOpt)
            .withOption(fieldOpt).create();

    try {
        Parser parser = new Parser();
        parser.setGroup(group);
        CommandLine cmdLine = parser.parse(args);

        if (cmdLine.hasOption(helpOpt)) {
            CommandLineUtil.printHelp(group);
            return;
        }

        File file = new File(cmdLine.getValue(inputOpt).toString());

        if (!file.isDirectory()) {
            throw new IllegalArgumentException(file + " does not exist or is not a directory");
        }

        long maxDocs = Long.MAX_VALUE;
        if (cmdLine.hasOption(maxOpt)) {
            maxDocs = Long.parseLong(cmdLine.getValue(maxOpt).toString());
        }

        if (maxDocs < 0) {
            throw new IllegalArgumentException("maxDocs must be >= 0");
        }

        String field = cmdLine.getValue(fieldOpt).toString();

        PrintWriter out = null;
        if (cmdLine.hasOption(outputOpt)) {
            out = new PrintWriter(new FileWriter(cmdLine.getValue(outputOpt).toString()));
        } else {
            out = new PrintWriter(new OutputStreamWriter(System.out, "UTF-8"));
        }

        File output = new File("/home/drew/taming-text/delicious/training");
        output.mkdirs();

        emitTextForTags(file, output);

        IOUtils.close(Collections.singleton(out));
    } catch (OptionException e) {
        log.error("Exception", e);
        CommandLineUtil.printHelp(group);
    }

}

From source file:Main.java

public static <K> Set<K> createSingletonSet(K item) {
    return Collections.singleton(item);
}

From source file:Main.java

public static Set<Object> singletonSet(Object object) {
    return Collections.singleton(object);
}

From source file:Main.java

/**
 * Removes null values from the given map
 *///from   w  w w  .j  ava2 s . co  m
public static void removeNullValues(Map<String, ?> map) {
    if (map == null)
        return;
    map.values().removeAll(Collections.singleton(null));
}

From source file:Main.java

public static void filterNull(Collection<?> collection) {
    if (isNotEmpty(collection)) {
        collection.removeAll(Collections.singleton(null));
    }/*w ww. j av  a 2 s. c o m*/
}

From source file:Main.java

public static <A> Set<A> makeSet(Collection<A> xs) {
    if (xs.size() == 0)
        return Collections.<A>emptySet();
    else if (xs.size() == 1)
        return Collections.singleton(xs.iterator().next());
    else {//from   w  w  w .ja  v  a 2  s  . c  o  m
        Set<A> set = new HashSet<A>(xs.size());
        set.addAll(xs);
        return set;
    }
}

From source file:Main.java

public static <T> Set<T> toImmutableSet(Set<T> set) {
    switch (set.size()) {
    case 0:/* ww w .  j  a  v a  2s .  co m*/
        return Collections.emptySet();
    case 1:
        return Collections.singleton(set.iterator().next());
    default:
        return Collections.unmodifiableSet(set);
    }
}

From source file:Main.java

/**
 * Convert a String to a unmodifiable set of characters.
 * @param str The string to convert/*from  w w  w .  j  a va2  s  .co  m*/
 * @return A set containing the characters in str. A empty set
 *    is returned if str is null.
 */
public static Set<Character> strToUnmodifiableSet(String str) {
    if (str == null)
        return Collections.emptySet();
    if (str.length() == 1)
        return Collections.singleton(str.charAt(0));
    return Collections.unmodifiableSet(strToSet(str));
}

From source file:Main.java

/**
 * Creates an unmodifiable set filled with the given values.
 * //from ww w.j  a v a2  s.  c  o  m
 * @param <T>
 *            the set's element type.
 * @param values
 *            the values.
 * @return a newly created set containing the given values.
 */
@SafeVarargs
public static <T> Set<T> createUnmodifiableSet(final T... values) {
    switch (values.length) {
    case 0:
        return Collections.emptySet();
    case 1:
        return Collections.singleton(values[0]);
    default:
        return Collections.unmodifiableSet(createHashSet(values));
    }
}

From source file:Main.java

@SafeVarargs
public static <A> Set<A> makeSet(A... xs) {
    if (xs.length == 0)
        return Collections.<A>emptySet();
    else if (xs.length == 1)
        return Collections.singleton(xs[0]);
    else {//www. ja v a  2  s.  c o  m
        Set<A> set = new HashSet<A>(xs.length);
        Collections.addAll(set, xs);
        return set;
    }
}