001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.util; 019 020import org.apache.commons.lang3.StringUtils; 021import org.apache.yetus.audience.InterfaceAudience; 022 023import org.apache.hbase.thirdparty.com.google.common.base.Joiner; 024import org.apache.hbase.thirdparty.com.google.common.base.Splitter; 025 026/** 027 * Utility for Strings. 028 */ 029@InterfaceAudience.Private 030public final class Strings { 031 public static final String DEFAULT_SEPARATOR = "="; 032 public static final String DEFAULT_KEYVALUE_SEPARATOR = ", "; 033 034 public static final Joiner JOINER = Joiner.on(","); 035 public static final Splitter SPLITTER = Splitter.on(","); 036 037 private Strings() { 038 } 039 040 /** 041 * Append to a StringBuilder a key/value. Uses default separators. 042 * @param sb StringBuilder to use 043 * @param key Key to append. 044 * @param value Value to append. 045 * @return Passed <code>sb</code> populated with key/value. 046 */ 047 public static StringBuilder appendKeyValue(final StringBuilder sb, final String key, 048 final Object value) { 049 return appendKeyValue(sb, key, value, DEFAULT_SEPARATOR, DEFAULT_KEYVALUE_SEPARATOR); 050 } 051 052 /** 053 * Append to a StringBuilder a key/value. Uses default separators. 054 * @param sb StringBuilder to use 055 * @param key Key to append. 056 * @param value Value to append. 057 * @param separator Value to use between key and value. 058 * @param keyValueSeparator Value to use between key/value sets. 059 * @return Passed <code>sb</code> populated with key/value. 060 */ 061 public static StringBuilder appendKeyValue(final StringBuilder sb, final String key, 062 final Object value, final String separator, final String keyValueSeparator) { 063 if (sb.length() > 0) { 064 sb.append(keyValueSeparator); 065 } 066 return sb.append(key).append(separator).append(value); 067 } 068 069 /** 070 * Given a PTR string generated via reverse DNS lookup, return everything except the trailing 071 * period. Example for host.example.com., return host.example.com 072 * @param dnPtr a domain name pointer (PTR) string. 073 * @return Sanitized hostname with last period stripped off. 074 */ 075 public static String domainNamePointerToHostName(String dnPtr) { 076 if (dnPtr == null) { 077 return null; 078 } 079 080 return dnPtr.endsWith(".") ? dnPtr.substring(0, dnPtr.length() - 1) : dnPtr; 081 } 082 083 /** 084 * Push the input string to the right by appending a character before it, usually a space. 085 * @param input the string to pad 086 * @param padding the character to repeat to the left of the input string 087 * @param length the desired total length including the padding 088 * @return padding characters + input 089 */ 090 public static String padFront(String input, char padding, int length) { 091 if (input.length() > length) { 092 throw new IllegalArgumentException("input \"" + input + "\" longer than maxLength=" + length); 093 } 094 int numPaddingCharacters = length - input.length(); 095 return StringUtils.repeat(padding, numPaddingCharacters) + input; 096 } 097}