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

@SuppressWarnings({ "rawtypes", "cast" })
public static List<String> getListStrings(final AbstractCollection collection) {
	if ((null != collection) && (collection.size() > 0)) {
		final List<String> result = new ArrayList<String>();
		if (collection.iterator().next() instanceof Object) {
			// treat as an object
			for (final Object o : collection) {
				if (null != o) {
					result.add(o.toString());
				}
			}

		} else {
			// treat as a primitive
			final Iterator it = collection.iterator();
			while (it.hasNext()) {
				result.add(String.valueOf(it.next()));
			}
		}

		return result;
	}

	return null;
}
 

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();
}
 

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();
}