java.util.AbstractCollection#isEmpty ( )源码实例Demo

private static String join(AbstractCollection<String> col, String delimiter) {
	if (col.isEmpty()) return "";
	Iterator<String> iter = col.iterator();
	StringBuffer buffer = new StringBuffer(iter.next());
	while(iter.hasNext()) buffer.append(delimiter).append(iter.next());
	return buffer.toString();
}
 

@Override
public Iterable<S> unmarshal(AbstractCollection<S> source) throws Exception {

  if (source == null || source.isEmpty()) {
    return Collections.emptyList();
  }

  return source;
}
 

public static String join(AbstractCollection<String> s, String delimiter) {
    if (s.isEmpty()) return "";
    Iterator<String> iter = s.iterator();
    StringBuffer buffer = new StringBuffer(iter.next());
    while (iter.hasNext()) {
        buffer.append(delimiter);
        buffer.append(iter.next());
    }
    return buffer.toString();
}
 

/**
 * Join multiple strings into a string delimited by the given delimiter.
 * 
 * @param s a collection of strings
 * @param delimiter the delimiter 
 * @return a 'delimiter' separated string
 */
public static String join(AbstractCollection<String> s, String delimiter) {
    if (s.isEmpty()) return "";
    Iterator<String> iter = s.iterator();
    StringBuffer buffer = new StringBuffer(iter.next());
    while (iter.hasNext()) {
        buffer.append(delimiter);
        buffer.append(iter.next());
    }
    return buffer.toString();
}
 

public static String join(AbstractCollection<String> s, String delimiter) {
    if (s == null || s.isEmpty()) return "";
    Iterator<String> iter = s.iterator();
    StringBuilder builder = new StringBuilder(iter.next());
    while( iter.hasNext() )
    {
	builder.append(delimiter).append(iter.next());
    }
    return builder.toString();
}