1/*
2 * Copyright 2008 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package org.mockftpserver.core.util;
17
18import java.util.Collection;
19import java.util.Iterator;
20
21/**
22 * Contains static String-related utility methods.
23 *
24 * @author Chris Mair
25 * @version $Revision$ - $Date$
26 */
27public class StringUtil {
28
29    /**
30     * Pad the specified String with spaces to the right to the specified width. If the length
31     * of string is already equal to or greater than width, then just return string.
32     *
33     * @param string - the String to pad
34     * @param width  - the target width
35     * @return a String of at least width characters, padded on the right with spaces as necessary
36     */
37    public static String padRight(String string, int width) {
38        int numSpaces = width - string.length();
39        return (numSpaces > 0) ? string + spaces(numSpaces) : string;
40    }
41
42    /**
43     * Pad the specified String with spaces to the left to the specified width. If the length
44     * of string is already equal to or greater than width, then just return string.
45     *
46     * @param string - the String to pad
47     * @param width  - the target width
48     * @return a String of at least width characters, padded on the left with spaces as necessary
49     */
50    public static String padLeft(String string, int width) {
51        int numSpaces = width - string.length();
52        return (numSpaces > 0) ? spaces(numSpaces) + string : string;
53    }
54
55    /**
56     * Join the Strings within the parts Collection, inserting the delimiter in between elements
57     *
58     * @param parts     - the Collection of Strings to join
59     * @param delimiter - the delimiter String to insert between the parts
60     * @return the Strings within the parts collection joined together using the specified delimiter
61     */
62    public static String join(Collection parts, String delimiter) {
63        Assert.notNull(parts, "parts");
64        Assert.notNull(delimiter, "delimiter");
65
66        StringBuffer buf = new StringBuffer();
67        Iterator iter = parts.iterator();
68        while (iter.hasNext()) {
69            String component = (String) iter.next();
70            buf.append(component);
71            if (iter.hasNext()) {
72                buf.append(delimiter);
73            }
74        }
75        return buf.toString();
76    }
77
78    //--------------------------------------------------------------------------
79    // Internal Helper Methods
80    //--------------------------------------------------------------------------
81
82    private static String spaces(int numSpaces) {
83        StringBuffer buf = new StringBuffer();
84        for (int i = 0; i < numSpaces; i++) {
85            buf.append(" ");
86        }
87        return buf.toString();
88    }
89
90    /**
91     * Private constructor to prevent instantiation. All members are static.
92     */
93    private StringUtil() {
94    }
95
96}