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      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  */
     16 package org.mockftpserver.core.util;
     17 
     18 import java.util.Collection;
     19 import java.util.Iterator;
     20 
     21 /**
     22  * Contains static String-related utility methods.
     23  *
     24  * @author Chris Mair
     25  * @version $Revision$ - $Date$
     26  */
     27 public 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 }