Java String Join join(String delimiter, Object... parts)

Description

join

License

Open Source License

Declaration

public static String join(String delimiter, Object... parts) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.util.*;

public class Main {
    public static String join(String delimiter, Object... parts) {
        return join(Arrays.asList(parts), delimiter);
    }/*from www .j  a  v a 2s  .c  o  m*/

    public static String join(Object[] parts, String delimiter) {
        return join(Arrays.asList(parts), delimiter);
    }

    /**
     * Joins the String values of the contents of the Object array (parts) by inserting (delimiter) between each String.
     * This is the counterpart to String.split() and does the exact opposite of String.split().
     * @param parts The Object array that contains the objects, the String values of which you want to join together.
     * @param delimiter The String to insert between each object's String value in (parts)
     * @return Returns a String object constructed by joining each String value of the objects in (parts) using
     *  String.valueOf() on each object and with the given (delimiter). Returns null if the (parts) array is null
     *  or returns the empty String if the (parts) array is empty. A null delimiter throws a NullPointerException.
     * @author: David Kovacs
     */
    public static String join(Iterable<?> parts, String delimiter) {
        if (parts == null)
            return null;
        if (delimiter == null)
            throw new NullPointerException(
                    "The delimiter cannnot be null. Use an empty string if you want no delimiter.");

        StringBuilder result = new StringBuilder();
        String currentDelim = null;
        for (Object part : parts) {
            if (currentDelim == null)
                currentDelim = delimiter;
            else
                result.append(currentDelim);
            result.append(String.valueOf(part));
        }
        return result.toString();
    }

    /** This works the same as {@link String#valueOf(Object)}, except it returns an empty string instead of "null" if the input is null. */
    public static String valueOf(Object o) {
        return o == null ? "" : String.valueOf(o);
    }
}

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