Example usage for java.util Collection isEmpty

Introduction

In this page you can find the example usage for java.util Collection isEmpty.

Prototype

boolean isEmpty();

Source Link

Document

Returns true if this collection contains no elements.

Usage

From source file:org.grails.datastore.mapping.redis.query.RedisQueryUtils.java

public static List<Long> transformRedisResults(ConversionService conversionService,
        Collection<String> results) {
    List<Long> returnResults;
    if (!results.isEmpty()) {
        List<Long> foreignKeys = new ArrayList<Long>();
        for (String result : results) {
            foreignKeys.add(conversionService.convert(result, Long.class));
        }//from   w  w w. j  a v  a 2  s.com
        returnResults = foreignKeys;
    } else {
        returnResults = Collections.emptyList();
    }
    return returnResults;
}

From source file:Main.java

public static String toString(Collection<Integer> stack, String delimiterChars) {
    if (stack.isEmpty()) {
        return "";
    }/*from   www .  ja  v  a  2 s  .c  o m*/
    if (stack.size() == 1) {
        return Integer.toString(stack.iterator().next());
    }
    StringWriter writer = new StringWriter();
    String delimiter = "";
    for (Integer item : stack) {
        writer.append(delimiter);
        writer.append(Integer.toString(item));
        delimiter = delimiterChars;
    }
    return writer.toString();
}

From source file:me.taylorkelly.mywarp.util.CommandUtils.java

/**
 * Joins all worlds in the given collection in one string, separated by {@code ", "}.
 *
 * @param worlds a collection of worlds//  w  w w  .  j a  va 2s  .c o m
 * @return a string with all world-names or {@code -} if the collection was empty
 */
public static String joinWorlds(Collection<LocalWorld> worlds) {
    if (worlds.isEmpty()) {
        return "-";
    }

    StrBuilder ret = new StrBuilder();
    for (LocalWorld world : worlds) {
        ret.appendSeparator(", ");
        ret.append(world.getName());
    }
    return ret.toString();
}

From source file:Main.java

/**
 * @param col to filter using Collections2.filter
 * @param predicate to use//from  w  w  w  .  java2  s  . com
 * @param fallbackPredicate to use if predicate resulted in empty collection
 * @param <T> type contained in the collection
 * @return the filtered collection
 */
public static <T> Collection<T> filter(Collection<T> col, Predicate<? super T> predicate,
        Predicate<? super T> fallbackPredicate) {
    Collection<T> result = Collections2.filter(col, predicate);
    if (result.isEmpty()) {
        return Collections2.filter(col, fallbackPredicate);
    }
    return result;
}

From source file:com.github.yongchristophertang.engine.AssertUtils.java

/**
 * Assert a collection of T instances is not empty.
 */// w  w  w .  j  av  a2s  .co m
public static <T> void collectionNotEmpty(Collection<T> collection, String message) {
    if (collection.isEmpty()) {
        throw new IllegalArgumentException(message);
    }
}

From source file:net.firejack.platform.core.utils.ArrayUtils.java

public static <T> T[] getArray(Collection<T> itemList, Class<T> clazz) {
    return itemList == null || itemList.isEmpty() ? null
            : itemList.toArray((T[]) Array.newInstance(clazz, itemList.size()));
}

From source file:Main.java

/**
 * /*from w w w.  ja v a 2 s.  co m*/
 * build a SQL IN clause from the array of parameters passed in
 * @param inListValues: components of the IN list
 * @return an empty string if the IN list will be empty
 */
protected static String inString(Collection<String> inListValues) {
    if (inListValues.isEmpty()) {
        return "";
    }
    // the delimiter for strings in the DB is assumed to be a single quote.
    // this is the ANSI-92 standard.
    // if the ArrayList input is empty, IN ('') is returned.
    StringBuilder inBuilder = new StringBuilder(150);
    inBuilder.append("('");
    boolean isFirst = true;
    for (String val : inListValues) {
        if (isFirst) {
            isFirst = false;
        } else {
            inBuilder.append("','");
        }
        inBuilder.append(val);
    }
    inBuilder.append("')");

    return inBuilder.toString();
}

From source file:Main.java

/**
 * Check whether a collection is null or empty.
 *
 * @param collection/*from www . j  a  va 2 s  .c om*/
 *            Collection to check.
 * @return {@code true} if the collection is {@code null} or {@link Collection#isEmpty()} returns {@code true}.
 */
public static boolean isEmpty(Collection<?> collection) {
    return collection == null || collection.isEmpty();
}

From source file:Main.java

/**
 * Utility method to check for a not empty {@link Collection} including a null check.
 *
 * @param collection {@link Collection} to test for non empty
 * @return true if collection is not null and has at least one entry.
 *//* ww w.ja  v  a 2 s.com*/
public static boolean isNotEmpty(final Collection<?> collection) {
    return collection != null && !collection.isEmpty();
}

From source file:Main.java

/**
 * Return {@code true} if any element in '{@code candidates}' is contained in
 * '{@code source}', otherwise returns {@code false}.
 * //from  w  w w  . jav a2s .  c  om
 * @param source
 *           the source Collection.
 * @param candidates
 *           the candidates to search for.
 * @return whether any of the candidates has been found.
 */
public static boolean containsAny(Collection<?> source, Object... candidates) {
    if (source == null || source.isEmpty() || candidates == null || candidates.length == 0) {
        return false;
    }
    for (Object candidate : candidates) {
        if (source.contains(candidate)) {
            return true;
        }
    }
    return false;
}