org.apache.hudi.common.util.StringUtils Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hudi.common.util;
import javax.annotation.Nullable;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* Simple utility for operations on strings.
*/
public class StringUtils {
public static final String EMPTY_STRING = "";
/**
*
* Joins the elements of the provided array into a single String containing the provided list of elements.
*
*
*
* No separator is added to the joined String. Null objects or empty strings within the array are represented by empty
* strings.
*
*
*
* StringUtils.join(null) = null
* StringUtils.join([]) = ""
* StringUtils.join([null]) = ""
* StringUtils.join(["a", "b", "c"]) = "abc"
* StringUtils.join([null, "", "a"]) = "a"
*
*/
public static String join(final String... elements) {
return join(elements, EMPTY_STRING);
}
public static String joinUsingDelim(String delim, final String... elements) {
return join(elements, delim);
}
public static String join(final String[] array, final String separator) {
if (array == null) {
return null;
}
return org.apache.hadoop.util.StringUtils.join(separator, array);
}
/**
* Wrapper of {@link java.lang.String#join(CharSequence, Iterable)}.
*
* Allow return {@code null} when {@code Iterable} is {@code null}.
*/
public static String join(CharSequence delimiter, Iterable elements) {
if (elements == null) {
return null;
}
return String.join(delimiter, elements);
}
public static String toHexString(byte[] bytes) {
StringBuilder sb = new StringBuilder(bytes.length * 2);
for (byte b : bytes) {
sb.append(String.format("%02x", b));
}
return sb.toString();
}
public static boolean isNullOrEmpty(String str) {
return str == null || str.length() == 0;
}
public static boolean nonEmpty(String str) {
return !isNullOrEmpty(str);
}
/**
* Returns the given string if it is non-null; the empty string otherwise.
*
* @param string the string to test and possibly return
* @return {@code string} itself if it is non-null; {@code ""} if it is null
*/
public static String nullToEmpty(@Nullable String string) {
return string == null ? "" : string;
}
public static String objToString(@Nullable Object obj) {
if (obj == null) {
return null;
}
return obj instanceof ByteBuffer ? toHexString(((ByteBuffer) obj).array()) : obj.toString();
}
/**
* Returns the given string if it is nonempty; {@code null} otherwise.
*
* @param string the string to test and possibly return
* @return {@code string} itself if it is nonempty; {@code null} if it is empty or null
*/
public static @Nullable String emptyToNull(@Nullable String string) {
return stringIsNullOrEmpty(string) ? null : string;
}
private static boolean stringIsNullOrEmpty(@Nullable String string) {
return string == null || string.isEmpty();
}
/**
* Splits input string, delimited {@code delimiter} into a list of non-empty strings
* (skipping any empty string produced during splitting)
*/
public static List split(@Nullable String input, String delimiter) {
if (isNullOrEmpty(input)) {
return Collections.emptyList();
}
return Stream.of(input.split(delimiter)).map(String::trim).filter(s -> !s.isEmpty()).collect(Collectors.toList());
}
}