Example usage for java.util Collections emptyMap

Introduction

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

Prototype

@SuppressWarnings("unchecked")
public static final <K, V> Map<K, V> emptyMap()

Source Link

Document

Returns an empty map (immutable).

Usage

From source file:Main.java

static <K, V> Map<K, V> getMap(Map<K, V> orig) {
    if (orig == null || orig.size() == 0) {
        return Collections.emptyMap();
    } else if (orig.size() == 1) {
        final Map.Entry<K, V> entry = orig.entrySet().iterator().next();
        return Collections.singletonMap(entry.getKey(), entry.getValue());
    } else {/*from   w ww  . j a v  a2s  . com*/
        return Collections.unmodifiableMap(new TreeMap<>(orig));
    }
}

From source file:Main.java

public static <V, K> Map<V, K> safe(Map<V, K> collection) {
    return collection == null ? Collections.emptyMap() : collection;
}

From source file:Main.java

/**
 * Returns an unmodifiable view of the specified {@code mapSet}. This
 *  method allows modules to provide users with "read-only" access to
 * {@link Map}, but also to the value {@link Set}.
 *
 * @param <K>/*from   w ww .  ja  v  a2  s  .  co  m*/
 *            the class of the map keys
 * @param <V>
 *            the class of the set values
 * @param mapSet
 *            the {@link Map} of {@link Set} for which an unmodifiable view
 *            is to be returned
 * @return an unmodifiable view of the specified map.
 *
 * @see Collections#unmodifiableMap(Map)
 * @see Collections#unmodifiableSet(Set)
 * @since 4.2
 */
@Nonnull
public static <K, V> Map<K, Set<V>> unmodifiableMapSet(@Nullable final Map<K, Set<V>> mapSet) {
    if (mapSet == null) {
        return Collections.emptyMap();
    }

    for (final Map.Entry<K, Set<V>> entry : mapSet.entrySet()) {
        final K key = entry.getKey();
        final Set<V> value = entry.getValue();

        mapSet.replace(key, Collections.unmodifiableSet(value));
    }

    return Collections.unmodifiableMap(mapSet);
}

From source file:Main.java

private static Map<Object, Object> createMap(Object... keysAndValues) {
    switch (keysAndValues.length) {
    case 0:/*  ww w  .j  a va 2s.  c o  m*/
        return Collections.emptyMap();
    case 2:
        return Collections.singletonMap(keysAndValues[0], keysAndValues[1]);
    }
    if (keysAndValues.length % 2 == 1) {
        throw new IllegalArgumentException("Odd number of createMap arguments");
    }

    final Map<Object, Object> map = new HashMap<Object, Object>();
    for (int i = 0; i < keysAndValues.length; i += 2) {
        map.put(keysAndValues[i], keysAndValues[i + 1]);
    }
    return map;
}

From source file:Main.java

/**
 * Creates an empty element mapping.//from  w  ww. ja  v  a  2s.  c  om
 *
 * @return the empty mapping
 */
private static Map<Node, Node> emptyElementMapping() {
    return Collections.emptyMap();
}

From source file:Main.java

public static Map<String, String> extractParameters(String exString) {
    exString = exString.trim();//from   www . j  a  va 2 s .  c  om

    int leftParIndex = exString.indexOf(LEFT_PARENTHESIS);
    if (leftParIndex == -1) {
        return Collections.emptyMap();
    }

    String paramsStr;
    if (exString.endsWith(")")) {
        paramsStr = exString.substring(leftParIndex + 1, exString.lastIndexOf(")"));
    } else {
        paramsStr = exString.substring(leftParIndex + 1, exString.length());
    }

    Map<String, String> parameters = new LinkedHashMap<String, String>();
    String[] paramsPairs = paramsStr.trim().split(",");
    for (String paramsPair : paramsPairs) {
        String[] keyValue = paramsPair.trim().split("=");
        if (keyValue.length == 2) {
            parameters.put(keyValue[0].trim(), keyValue[1].trim());
        }
    }
    return parameters;
}

From source file:com.linecorp.armeria.server.docs.FieldInfo.java

static FieldInfo of(FieldMetaData fieldMetaData) {
    return of(fieldMetaData, null, Collections.emptyMap());
}

From source file:com.linecorp.armeria.server.docs.MapInfo.java

static MapInfo of(MapMetaData mapMetaData) {
    return of(mapMetaData, null, Collections.emptyMap());
}

From source file:Main.java

public static Map<String, String> attributesToMap(String scope, XMLStreamReader reader) {
    int numAttrs = reader.getAttributeCount();
    if (numAttrs == 0) {
        return Collections.emptyMap();
    }/*  w w w. j  a v  a 2  s .c  o  m*/
    Map<String, String> rtn = new HashMap<String, String>(numAttrs);
    for (int i = 0; i < numAttrs; i++) {
        StringBuilder attrName = new StringBuilder();
        if (scope.length() > 0) {
            attrName.append(scope).append(SCOPE_SEP);
        }
        attrName.append(reader.getAttributeName(i).toString());
        rtn.put(attrName.toString(), reader.getAttributeValue(i));
    }
    return rtn;
}

From source file:com.openshift.internal.util.URIUtils.java

public static Map<String, String> splitFragment(String location) {
    if (StringUtils.isEmpty(location)) {
        return Collections.emptyMap();
    }/*from   w  w w.j a  va2s.  c om*/
    URI uri = null;
    try {
        uri = new URI(location);
    } catch (URISyntaxException e) {
        throw new RuntimeException(e);
    }
    return splitFragment(uri);
}