Example usage for java.util Collections emptySet

Introduction

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

Prototype

@SuppressWarnings("unchecked")
public static final <T> Set<T> emptySet()

Source Link

Document

Returns an empty set (immutable).

Usage

From source file:Main.java

/**
 * Returns <code>theSet</code> if it is not <code>null</code> or
 * an unmodifiable singleton empty set (see {@link Collections#emptySet()}).
 * @param <T>/*from   w w w.j a  v a 2  s.  c o m*/
 * @param theSet
 * @return
 */
public static <T> Set<T> emptySetIfNull(final Set<T> theSet) {
    if (theSet == null)
        return Collections.emptySet();
    else
        return theSet;
}

From source file:me.smoe.adar.utils.cam.o.common.SentenceAnalyzer.java

public static Set<String> analyzer(String sentence) throws Exception {
    if (StringUtils.isEmpty(sentence)) {
        return Collections.emptySet();
    }//  w  w  w.java2s  .com

    Analyzer analyzer = new StandardAnalyzer();
    try {
        TokenStream tokenStream = analyzer.tokenStream(StringUtils.EMPTY, new StringReader(sentence));
        tokenStream.addAttribute(CharTermAttribute.class);
        tokenStream.reset();

        Set<String> words = new LinkedHashSet<>();
        while (tokenStream.incrementToken()) {
            String word = ((CharTermAttribute) tokenStream.getAttribute(CharTermAttribute.class)).toString();

            if (word.length() <= 1) {
                continue;
            }

            words.add(word);
        }

        return words;
    } finally {
        analyzer.close();
    }
}

From source file:io.syndesis.credential.CredentialFlowStateHelper.java

static Set<CredentialFlowState> restoreFrom(final Restorer restore,
        final HttpServletRequest request) {
    final Cookie[] servletCookies = request.getCookies();

    if (ArrayUtils.isEmpty(servletCookies)) {
        return Collections.emptySet();
    }// w  ww .  j  av a 2  s.co  m

    final List<javax.ws.rs.core.Cookie> credentialCookies = Arrays.stream(servletCookies)
            .filter(c -> c.getName().startsWith(CredentialFlowState.CREDENTIAL_PREFIX))
            .map(CredentialFlowStateHelper::toJaxRsCookie).collect(Collectors.toList());

    try {
        return restore.apply(credentialCookies, CredentialFlowState.class);
    } catch (final IllegalArgumentException e) {
        return Collections.emptySet();
    }
}

From source file:net.openid.appauth.AdditionalParamsProcessor.java

static Set<String> builtInParams(String... params) {
    if (params == null || params.length == 0) {
        return Collections.emptySet();
    }/*  w  ww .ja  v  a  2  s  .c o  m*/

    return Collections.unmodifiableSet(new HashSet<>(Arrays.asList(params)));
}

From source file:Main.java

private static <T> Set<T> _asSet(T[] a, boolean makeImmutable) {
    int count = (a != null) ? a.length : 0;

    Set<T> outSet;/*from  ww w . j  a  v  a2  s. co m*/

    if (count == 0) {
        outSet = Collections.emptySet();
    } else {
        if (count == 1) {
            outSet = Collections.singleton(a[0]);
        } else {
            // make the initial size big enough that we don't have to rehash to fit the array, for
            // the .75 load factor we pass in
            int initialSize = (int) Math.ceil(count / .75d);

            outSet = new HashSet<T>(initialSize, .75f);

            for (int i = 0; i < count; i++) {
                outSet.add(a[i]);
            }

            if (makeImmutable) {
                outSet = Collections.unmodifiableSet(outSet);
            }
        }
    }

    return outSet;
}

From source file:Main.java

public static final Set<String> stringArrayToSet(final String[] array) {
    if (array == null) {
        return Collections.emptySet();
    }//from  w ww  .  ja  v  a 2 s . co  m
    Set<String> tmp = new LinkedHashSet<>();
    for (String part : array) {
        String trimmed = part.trim();
        if (trimmed.length() > 0) {
            tmp.add(trimmed.intern());
        }
    }
    return tmp;
}

From source file:Main.java

/**
 * @param orig// w  w  w .j  a  va 2 s .co  m
 *            if null, return intersect
 */
public static Set<? extends Object> intersectSet(Set<? extends Object> orig, Set<? extends Object> intersect) {
    if (orig == null)
        return intersect;
    if (intersect == null || orig.isEmpty())
        return Collections.emptySet();
    Set<Object> set = new HashSet<Object>(orig.size());
    for (Object p : orig) {
        if (intersect.contains(p))
            set.add(p);
    }
    return set;
}

From source file:Main.java

public static <T> Set<T> inter(final List<Set<T>> sets) {
    final List<Set<T>> mutable = new ArrayList<Set<T>>(sets.size());
    for (final Set<T> s : sets) {
        // ignore nulls
        if (s != null)
            mutable.add(s);//w w  w .  j  a  v  a2 s  . co  m
    }

    if (mutable.isEmpty())
        return null;
    else if (mutable.size() == 1)
        return mutable.get(0);

    final int indexMin = indexOfMinSize(mutable);
    if (indexMin != 0) {
        mutable.add(0, mutable.remove(indexMin));
        return inter(mutable);
    }

    if (mutable.get(0).isEmpty())
        return Collections.emptySet();

    // replace the first 2 by their intersection
    // (inter will swap as appropriate if java doesn't evalute args in source order)
    mutable.add(0, inter(mutable.remove(0), mutable.remove(0)));
    return inter(mutable);
}

From source file:org.jboss.capedwarf.connect.server.HttpHeaders.java

/**
 * Get headers; read-only./*  w w w  .  j  av  a 2s.co  m*/
 *
 * @return the headers
 */
public static Set<Header> getHeaders() {
    Set<Header> set = tlh.get();
    if (set == null)
        return Collections.emptySet();

    return Collections.unmodifiableSet(set);
}

From source file:com.igitras.codegen.common.utils.Utils.java

public static <T> boolean checkCollectionEqual(Collection<T> from, Collection<T> to) {
    if (from == null) {
        from = Collections.emptySet();
    }//w  w  w.  j  a v  a  2s .  c o m

    if (to == null) {
        to = Collections.emptySet();
    }

    for (T t : from) {
        if (!to.contains(t)) {
            return false;
        }
    }

    for (T t : to) {
        if (!from.contains(t)) {
            return false;
        }
    }

    return true;
}