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 java.io.UnsupportedEncodingException;
021import java.net.URI;
022import java.net.URLDecoder;
023import java.nio.charset.StandardCharsets;
024import java.util.Collections;
025import java.util.Map;
026import java.util.stream.Collectors;
027import org.apache.commons.lang3.StringUtils;
028import org.apache.hadoop.conf.Configuration;
029import org.apache.yetus.audience.InterfaceAudience;
030
031import org.apache.hbase.thirdparty.com.google.common.base.Joiner;
032import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
033
034/**
035 * Utility for Strings.
036 */
037@InterfaceAudience.Private
038public final class Strings {
039  public static final String DEFAULT_SEPARATOR = "=";
040  public static final String DEFAULT_KEYVALUE_SEPARATOR = ", ";
041
042  public static final Joiner JOINER = Joiner.on(",");
043  public static final Splitter SPLITTER = Splitter.on(",");
044
045  private Strings() {
046  }
047
048  /**
049   * Append to a StringBuilder a key/value. Uses default separators.
050   * @param sb    StringBuilder to use
051   * @param key   Key to append.
052   * @param value Value to append.
053   * @return Passed <code>sb</code> populated with key/value.
054   */
055  public static StringBuilder appendKeyValue(final StringBuilder sb, final String key,
056    final Object value) {
057    return appendKeyValue(sb, key, value, DEFAULT_SEPARATOR, DEFAULT_KEYVALUE_SEPARATOR);
058  }
059
060  /**
061   * Append to a StringBuilder a key/value. Uses default separators.
062   * @param sb                StringBuilder to use
063   * @param key               Key to append.
064   * @param value             Value to append.
065   * @param separator         Value to use between key and value.
066   * @param keyValueSeparator Value to use between key/value sets.
067   * @return Passed <code>sb</code> populated with key/value.
068   */
069  public static StringBuilder appendKeyValue(final StringBuilder sb, final String key,
070    final Object value, final String separator, final String keyValueSeparator) {
071    if (sb.length() > 0) {
072      sb.append(keyValueSeparator);
073    }
074    return sb.append(key).append(separator).append(value);
075  }
076
077  /**
078   * Given a PTR string generated via reverse DNS lookup, return everything except the trailing
079   * period. Example for host.example.com., return host.example.com
080   * @param dnPtr a domain name pointer (PTR) string.
081   * @return Sanitized hostname with last period stripped off.
082   */
083  public static String domainNamePointerToHostName(String dnPtr) {
084    if (dnPtr == null) {
085      return null;
086    }
087
088    return dnPtr.endsWith(".") ? dnPtr.substring(0, dnPtr.length() - 1) : dnPtr;
089  }
090
091  /**
092   * Push the input string to the right by appending a character before it, usually a space.
093   * @param input   the string to pad
094   * @param padding the character to repeat to the left of the input string
095   * @param length  the desired total length including the padding
096   * @return padding characters + input
097   */
098  public static String padFront(String input, char padding, int length) {
099    if (input.length() > length) {
100      throw new IllegalArgumentException("input \"" + input + "\" longer than maxLength=" + length);
101    }
102    int numPaddingCharacters = length - input.length();
103    return StringUtils.repeat(padding, numPaddingCharacters) + input;
104  }
105
106  /**
107   * Parse the query string of an URI to a key value map. If a single key occurred multiple times,
108   * only the first one will take effect.
109   */
110  public static Map<String, String> parseURIQueries(URI uri) {
111    if (StringUtils.isBlank(uri.getRawQuery())) {
112      return Collections.emptyMap();
113    }
114    return Splitter.on('&').trimResults().splitToStream(uri.getRawQuery()).map(kv -> {
115      int idx = kv.indexOf('=');
116      try {
117        if (idx > 0) {
118          return Pair.newPair(
119            URLDecoder.decode(kv.substring(0, idx), StandardCharsets.UTF_8.name()),
120            URLDecoder.decode(kv.substring(idx + 1), StandardCharsets.UTF_8.name()));
121        } else {
122          return Pair.newPair(URLDecoder.decode(kv, StandardCharsets.UTF_8.name()), "");
123        }
124      } catch (UnsupportedEncodingException e) {
125        // should not happen
126        throw new AssertionError(e);
127      }
128    }).collect(Collectors.toMap(Pair::getFirst, Pair::getSecond, (v1, v2) -> v1));
129  }
130
131  /**
132   * Apply the key value pairs in the query string of the given URI to the given Configuration. If a
133   * single key occurred multiple times, only the first one will take effect.
134   */
135  public static void applyURIQueriesToConf(URI uri, Configuration conf) {
136    parseURIQueries(uri).forEach(conf::set);
137  }
138}