Example usage for java.util Collection size

Introduction

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

Prototype

int size();

Source Link

Document

Returns the number of elements in this collection.

Usage

From source file:Main.java

public static <T> T getUnique(Collection<T> list) {
    if (list == null)
        throw new IllegalArgumentException(" collection is null! collection must be not null");
    else if (list.size() != 1)
        throw new IllegalArgumentException(
                list.size() + " collection must be unique : " + list.iterator().next().toString());
    else/*from  w  w w  . j ava  2 s .  com*/
        return list.iterator().next();
}

From source file:Main.java

/**
 * Determines if a collection is empty/*from   w  w  w  .ja  va  2  s .  com*/
 * 
 * @param collection 
 * @return true if the collection is empty
 */
@SuppressWarnings("unchecked")
public static boolean isEmpty(Collection collection) {
    boolean empty = false;
    if (collection == null) {
        empty = true;
    } else if (collection.size() <= 0) {
        empty = true;
    }
    return empty;
}

From source file:Main.java

/**
 * // w  w w  .ja  v a 2  s . co  m
 * @param c1
 * @param s1
 * @return c1 - s1
 * 
 */
public static <T> List<T> minius(Collection<T> c1, Collection<T> s1) {

    if (c1 == null) {
        return Collections.emptyList();
    }

    if (s1 == null || s1.size() == 0) {
        return new ArrayList<T>(c1);
    }
    List<T> list = new ArrayList<T>();
    for (T t : c1) {
        if (!s1.contains(t)) {
            list.add(t);
        }
    }
    return list;
}

From source file:Main.java

public static String[] asArray(Object object) {
    if (object == null) {
        return null;
    }/*from w  ww .  ja  v a  2s  .com*/

    Class componentType = object.getClass().getComponentType();

    if (String.class.equals(componentType)) {
        return (String[]) object;
    } else if (componentType != null) {
        Object[] objects = (Object[]) object;
        String[] result = new String[objects.length];
        for (int i = 0; i < objects.length; i++) {
            Object o = objects[i];
            if (o == null) {
                continue;
            }

            result[i] = o.toString();
        }

        return result;
    } else if (object instanceof Collection) {
        Collection collection = (Collection) object;
        String[] result = new String[collection.size()];
        Iterator iterator = collection.iterator();

        for (int i = 0; i < result.length; i++) {
            Object next = iterator.next();
            if (next == null) {
                continue;
            }

            result[i] = next.toString();
        }

        return result;
    } else {
        String string = object.toString().trim();
        String[] split = string.split("\\s*,\\s*");
        return split;
    }
}

From source file:Main.java

/**
 * Join a bunch of objects into a string delimited by the separator
 *
 * @param sep//from   w w  w.j  ava  2s . co  m
 * @param c
 * @return
 */
public static String join(final String sep, final Collection<? extends Object> c) {
    if (c == null) {
        return null;
    }
    if (c.size() == 1) {
        return String.valueOf(c.iterator().next());
    }
    if (c.size() == 0) {
        return "";
    }
    final StringBuilder sb = new StringBuilder();
    String s = "";
    for (final Object o : c) {
        sb.append(s).append(String.valueOf(o));
        s = sep;
    }
    return sb.toString();
}

From source file:com.goncalomb.bukkit.bkglib.namemaps.EnchantmentsMap.java

public static List<String> getNames(Collection<Enchantment> enchantments) {
    ArrayList<String> names = new ArrayList<String>(enchantments.size());
    for (Enchantment enchantment : enchantments) {
        names.add(getName(enchantment));
    }/*from   w w  w.j  a  va2 s . co  m*/
    return names;
}

From source file:Main.java

public static boolean containsDuplicates(Collection<?> coll) {
    if (coll == null)
        throw new IllegalArgumentException();

    Set<Object> set = new HashSet<>(coll);

    return set.size() != coll.size();
}

From source file:Main.java

/**
 * Determines the size of the given collection, checking for null.
 *
 * @param   collection/*from w w w  .j a v  a  2  s.com*/
 *      The collection to get the size of.
 * @return
 *      The size of the collection. If it is null, zero is returned.
 */
public static int size(final Collection<?> collection) {
    if (collection == null) {
        return 0;
    } else {
        return collection.size();
    }
}

From source file:Main.java

public static String toString(Collection<Integer> stack, String delimiterChars) {
    if (stack.isEmpty()) {
        return "";
    }/*from   w w w .  j  av  a2 s .com*/
    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:Main.java

public static long[] toPrimitiveLongArray(Collection<Long> collection) {
    // Need to do this manually because we're converting to a primitive long array, not
    // a Long array.
    final int size = collection.size();
    final long[] ret = new long[size];
    // Collection doesn't have get(i).  (Iterable doesn't have size())
    int i = 0;//from   www  .j  a va2  s. c o m
    for (Long value : collection) {
        ret[i++] = value;
    }
    return ret;
}