Java Collection Join join(final String d, final Collection c)

Description

Behaves like Perl's join function.

License

Open Source License

Parameter

Parameter	Description
d	the delimiter to put between the elements
c	the collection from where to take the elements

Exception

Parameter	Description
NullPointerException	if the collection is <code>null</code>

Return

the constructed string

Declaration

public static String join(final String d, final Collection<? extends Object> c) 

Method Source Code

//package com.java2s;
/*/*from  www .ja  v a2s  .com*/
 * Integrated Rule Inference System (IRIS):
 * An extensible rule inference system for datalog with extensions.
 * 
 * Copyright (C) 2008 Semantic Technology Institute (STI) Innsbruck, 
 * University of Innsbruck, Technikerstrasse 21a, 6020 Innsbruck, Austria.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
 * MA  02110-1301, USA.
 */

import java.util.Collection;

public class Main {
    /**
     * Behaves like Perl's join function. Concats all elements of the colleciton
     * separated by the given delimiter.
     * 
     * @param d
     *            the delimiter to put between the elements
     * @param c
     *            the collection from where to take the elements
     * @return the constructed string
     * @throws NullPointerException
     *             if the delimiter is <code>null</code>
     * @throws NullPointerException
     *             if the collection is <code>null</code>
     * @since 0.3
     */
    public static String join(final String d, final Collection<? extends Object> c) {
        if (d == null) {
            throw new NullPointerException("The delimiter must not be null");
        }
        if (c == null) {
            throw new NullPointerException("The collection must not be null");
        }

        if (c.isEmpty()) {
            return "";
        }

        final StringBuilder b = new StringBuilder();
        boolean first = true;
        for (final Object o : c) {
            if (first)
                first = false;
            else
                b.append(d);
            b.append(o);
        }
        return b.toString();
    }
}

Related

1. join(final Collection values, final char separator)
2. join(final Collection collection)
3. join(final Collection collection, final String delimiter)
4. join(final Collection objs, final String delimiter)
5. join(final Collection objs, String delimiter)
6. join(final String delimiter, final Collection elements)
7. join(final String s, final Collection c)
8. join(final String sep, final Collection c)
9. join(final String sep, final Collection strs)