org.apache.logging.log4j.util.Strings 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.logging.log4j.util;
/**
* Consider this class private.
*
* @see Apache Commons Lang
*/
public final class Strings {
/**
* The empty string.
*/
public static final String EMPTY = "";
private Strings() {
}
/**
*
* Checks if a CharSequence is empty ("") or null.
*
*
*
* Strings.isEmpty(null) = true
* Strings.isEmpty("") = true
* Strings.isEmpty(" ") = false
* Strings.isEmpty("bob") = false
* Strings.isEmpty(" bob ") = false
*
*
*
* NOTE: This method changed in Lang version 2.0. It no longer trims the CharSequence. That functionality is
* available in isBlank().
*
*
*
* Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isEmpty(CharSequence)
*
*
* @param cs
* the CharSequence to check, may be null
* @return {@code true} if the CharSequence is empty or null
*/
public static boolean isEmpty(final CharSequence cs) {
return cs == null || cs.length() == 0;
}
/**
*
* Checks if a CharSequence is not empty ("") and not null.
*
*
*
* Strings.isNotEmpty(null) = false
* Strings.isNotEmpty("") = false
* Strings.isNotEmpty(" ") = true
* Strings.isNotEmpty("bob") = true
* Strings.isNotEmpty(" bob ") = true
*
*
*
* Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isNotEmpty(CharSequence)
*
*
* @param cs
* the CharSequence to check, may be null
* @return {@code true} if the CharSequence is not empty and not null
*/
public static boolean isNotEmpty(final CharSequence cs) {
return !isEmpty(cs);
}
/**
* Checks if a String is blank. A blank string is one that is {@code null}, empty, or when trimmed using
* {@link String#trim()} is empty.
*
* @param s
* the String to check, may be {@code null}
* @return {@code true} if the String is {@code null}, empty, or trims to empty.
*/
public static boolean isBlank(final String s) {
return s == null || s.trim().isEmpty();
}
/**
* Checks if a String is not blank. The opposite of {@link #isBlank(String)}.
*
* @param s
* the String to check, may be {@code null}
* @return {@code true} if the String is non-{@code null} and has content after being trimmed.
*/
public static boolean isNotBlank(final String s) {
return !isBlank(s);
}
/**
*
* Removes control characters (char <= 32) from both ends of this String returning {@code null} if the String is
* empty ("") after the trim or if it is {@code null}.
*
*
* The String is trimmed using {@link String#trim()}. Trim removes start and end characters <= 32.
*
*
*
* Strings.trimToNull(null) = null
* Strings.trimToNull("") = null
* Strings.trimToNull(" ") = null
* Strings.trimToNull("abc") = "abc"
* Strings.trimToNull(" abc ") = "abc"
*
*
*
* Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.trimToNull(String)
*
*
* @param str
* the String to be trimmed, may be null
* @return the trimmed String, {@code null} if only chars <= 32, empty or null String input
*/
public static String trimToNull(final String str) {
final String ts = str == null ? null : str.trim();
return isEmpty(ts) ? null : ts;
}
/**
* Returns a quoted string.
*
* @param str
* a String
* @return {@code 'str'}
*/
public static String quote(final String str) {
return Chars.QUOTE + str + Chars.QUOTE;
}
/**
* Returns a double quoted string.
*
* @param str
* a String
* @return {@code "str"}
*/
public static String dquote(final String str) {
return Chars.DQUOTE + str + Chars.DQUOTE;
}
}