Java SortedMap Usage firstElement(Collection c)

Description

first Element

License

Open Source License

Declaration

public static <T> T firstElement(Collection<T> c) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright (c) 2010-2015 BSI Business Systems Integration AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors://  w  ww.ja  v  a 2  s  .co  m
 *     BSI Business Systems Integration AG - initial API and implementation
 ******************************************************************************/

import java.util.Collection;

import java.util.List;

import java.util.SortedMap;

public class Main {
    @SuppressWarnings("unchecked")
    public static <T> T firstElement(Object c) {
        if (c instanceof Collection<?>) {
            return (T) firstElement((Collection<?>) c);
        }
        return null;
    }

    public static <T> T firstElement(Collection<T> c) {
        if (isEmpty(c)) {
            return null;
        }
        return c.iterator().next();
    }

    public static <T> T firstElement(List<T> c) {
        if (isEmpty(c)) {
            return null;
        }
        return c.get(0);
    }

    public static <T, U> U firstElement(SortedMap<T, U> m) {
        if (m == null || m.isEmpty()) {
            return null;
        }
        return m.get(m.firstKey());
    }

    public static boolean isEmpty(Collection<?> c) {
        return c == null || c.isEmpty();
    }
}

Related

1. computeByteSizeM( SortedMap byteSizeByName)
2. computePathCauselessLms( List>> depCausesByNameList)
3. filterPrefix( SortedMap baseMap, String prefix)
4. find(SortedMap map, String baseName)
5. firstElement(Collection c)
6. generatePropertiesFilter(SortedMap propertiesMap)
7. getAll(SortedMap map)
8. getObjectSortedMap(SortedMap map, T key)