FbUtility.java

package eoc.studio.voicecard.facebook.utils;

import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

public class FbUtility {
    public static final String EMPTY = "";
    /**
     * <p>
     * Joins the elements of the provided {@code Iterator} into a single String containing the provided
     * elements.
     * </p>
     * 
     * <p>
     * No delimiter is added before or after the list. Null objects or empty strings within the iteration are
     * represented by empty strings.
     * </p>
     * 
     * <p>
     * See the examples here: {@link #join(Object[],char)}.
     * </p>
     * 
     * @param iterator the {@code Iterator} of values to join together, may be null
     * @param separator the separator character to use
     * @return the joined String, {@code null} if null iterator input
     * @since 2.0
     */
    public static String join(Iterator<?> iterator, char separator)
    {

        // handle null, zero and one elements before building a buffer
        if (iterator == null)
        {
            return null;
        }
        if (!iterator.hasNext())
        {
            return EMPTY;
        }
        Object first = iterator.next();
        if (!iterator.hasNext())
        {
            return first == null? "": first.toString();
        }

        // two or more elements
        StringBuilder buf = new StringBuilder(256); // Java default is 16, probably too small
        if (first != null)
        {
            buf.append(first);
        }

        while (iterator.hasNext())
        {
            buf.append(separator);
            Object obj = iterator.next();
            if (obj != null)
            {
                buf.append(obj);
            }
        }

        return buf.toString();
    }

    public static String join(Map<?, ?> map, char separator, char valueStartChar, char valueEndChar)
    {

        // handle null, zero and one elements before building a buffer
        if (map == null)
        {
            return null;
        }
        if (map.size() == 0)
        {
            return EMPTY;
        }

        // two or more elements
        StringBuilder buf = new StringBuilder(256); // Java default is 16, probably too small

        boolean isFirst = true;
        for (Entry<?, ?> entry: map.entrySet())
        {
            if (isFirst)
            {
                buf.append(entry.getKey());
                buf.append(valueStartChar);
                buf.append(entry.getValue());
                buf.append(valueEndChar);
                isFirst = false;
            }
            else
            {
                buf.append(separator);
                buf.append(entry.getKey());
                buf.append(valueStartChar);
                buf.append(entry.getValue());
                buf.append(valueEndChar);
            }
        }

        return buf.toString();
    }
}