Java Collection Join join(String delimiter, Collection parts)

Description

join

License

Open Source License

Declaration

public static String join(String delimiter, Collection<?> parts) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright (c) 2010-2015 BSI Business Systems Integration AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors://from w  w w  . j a v  a2  s .c  o m
 *     BSI Business Systems Integration AG - initial API and implementation
 ******************************************************************************/

import java.util.Collection;

public class Main {
    private static final String[] EMPTY_ARRAY = new String[0];

    /**
     * Concatenates the raw input of {@link Object}s separated by <code>delimiter</code>. On each object
     * {@link Object#toString()} is invoked.<br />
     * <code>null</code> values or those {@link Object#toString()} is empty are neglected.
     *
     * @param delimiter
     * @param values
     * @return never <code>null</code>, empty String in case no elements are appended
     * @since 3.8.1
     */
    public static String join(String delimiter, Object... parts) {
        if (parts == null || parts.length == 0) {
            return "";
        }
        boolean added = false;
        StringBuilder builder = new StringBuilder();
        for (Object o : parts) {
            if (o == null) {
                continue;
            }
            String s = o.toString();
            if (!isNullOrEmpty(s)) {
                if (added && delimiter != null) {
                    builder.append(delimiter);
                }
                builder.append(s);
                added = true;
            }
        }
        return builder.toString();
    }

    /**
     * @see #join(String, Object...)
     * @since 4.0.0
     */
    public static String join(String delimiter, Long[] parts) {
        return join(delimiter, (Object[]) parts);
    }

    /**
     * @see #join(String, Object...)
     * @since 3.8.1
     */
    public static String join(String delimiter, String[] parts) {
        return join(delimiter, (Object[]) parts);
    }

    /**
     * @see #join(String, Object...)
     * @since 4.0.0
     */
    public static String join(String delimiter, Collection<?> parts) {
        return join(delimiter, parts == null ? EMPTY_ARRAY : parts.toArray());
    }

    /**
     * Checks whether a given string is {@code null} or empty. A string is considered empty if it equals the empty string
     * "" (internally this method checks whether the string length is 0).
     *
     * @param s
     *          the string to be checked
     * @return {@code true} if {@code s} is {@code null} or equals the empty string, {@code false} otherwise
     */
    public static boolean isNullOrEmpty(CharSequence s) {
        return s == null || s.length() == 0;
    }

    public static int length(CharSequence s) {
        if (s == null) {
            return 0;
        } else {
            return s.length();
        }
    }
}

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