Example usage for java.util Collections emptyList

Introduction

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

Prototype

@SuppressWarnings("unchecked")
public static final <T> List<T> emptyList()

Source Link

Document

Returns an empty list (immutable).

Usage

From source file:Main.java

public static <K, V> List<V> getValueList(Map<K, List<V>> map, K key) {
    List<V> valueList = map.get(key);
    if (valueList == null)
        return Collections.emptyList();
    return valueList;
}

From source file:Main.java

public static <T> List<T> asList(T... args) {
    if (args == null || args.length == 0) {
        return Collections.emptyList();
    }/*  w  ww .j  a  va 2  s .  c o m*/

    return Arrays.asList(args);
}

From source file:Main.java

public static <T> Collection<T> unmodifiableCollection(Collection<? extends T> collection) {
    if (collection == null) {
        return Collections.emptyList();
    } else {//from w  w w .  j av a  2s .com
        return Collections.unmodifiableCollection(collection);
    }
}

From source file:Main.java

public static <T> List<T> safe(List<T> l) {
    if (l == null) {
        return Collections.emptyList();
    }/*from w  ww .  j av  a  2  s .  c  o m*/
    return l;
}

From source file:Main.java

public static List<Thread> getGroupThreads(ThreadGroup threadGroup) {
    if (threadGroup == null) {
        return Collections.emptyList();
    }//  ww  w . j a v  a 2 s. c  om

    Thread[] threadArray = new Thread[threadGroup.activeCount() * 2];
    threadGroup.enumerate(threadArray);
    return Arrays.asList(threadArray);
}

From source file:Main.java

/**
 * If list is null, change to empty list
 *//*from   w ww  .  j ava  2  s  .  c  o m*/
public static <T> List<T> notNull(List<T> list) {
    if (list == null) {
        return Collections.emptyList();
    }
    return list;
}

From source file:Main.java

public static <V> List<V> subList(List<V> list, int startIndex, int count) {
    if (null == list || startIndex >= list.size() || count <= 0) {
        return Collections.emptyList();
    }//from   w  ww .j a v a2 s. com
    int endIndex = Math.min(startIndex + count, list.size());
    return list.subList(startIndex, endIndex);
}

From source file:Main.java

public static <T> List<T> nonNullList(final List<T> list) {
    if (list == null) {
        return Collections.emptyList();
    }/*from   www. j av a  2s .c o  m*/

    return list;
}

From source file:Main.java

public static <T> List<T> readOnlyCopy(List<T> orig) {
    if (orig.isEmpty())
        return Collections.emptyList();
    if (orig.size() == 1)
        return Collections.singletonList(orig.get(0));
    ArrayList<T> copy = new ArrayList<>(orig.size());
    copy.addAll(orig);//from ww w. j  av a2s . c  o  m
    return Collections.unmodifiableList(copy);
}

From source file:Main.java

public static <T> List<T> circleSubList(List<T> srcList, int position, int count) {
    if (srcList == null || srcList.size() == 0) {
        return Collections.emptyList();
    }/* w  w  w. j a v  a 2s  .c  o  m*/
    position = position < 0 ? 0 : position;
    count = count > srcList.size() ? srcList.size() : count;
    if (position > srcList.size() - 1) {
        return srcList.subList(0, count);
    }
    if (position + count <= srcList.size()) {
        return srcList.subList(position, (position + count));
    }
    List<T> fList = srcList.subList(position, srcList.size());
    List<T> eList = srcList.subList(0, count - srcList.size() + position);
    fList.addAll(eList);
    return fList;
}