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/**
* Copyright (c) 2013, impossibl.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of impossibl.com nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed 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 com.impossibl.postgres.utils.guava;
import static com.impossibl.postgres.utils.guava.Preconditions.*;
public class Strings {
/**
* 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(String string) {
return (string == null) ? "" : string;
}
/**
* 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 String emptyToNull(String string) {
return isNullOrEmpty(string) ? null : string;
}
/**
* Returns {@code true} if the given string is null or is the empty string.
*
* Consider normalizing your string references with {@link #nullToEmpty}.
* If you do, you can use {@link String#isEmpty()} instead of this
* method, and you won't need special null-safe forms of methods like {@link
* String#toUpperCase} either. Or, if you'd like to normalize "in the other
* direction," converting empty strings to {@code null}, you can use {@link
* #emptyToNull}.
*
* @param string a string reference to check
* @return {@code true} if the string is null or is the empty string
*/
public static boolean isNullOrEmpty(String string) {
return string == null || string.length() == 0; // string.isEmpty() in Java 6
}
/**
* Returns a string, of length at least {@code minLength}, consisting of
* {@code string} prepended with as many copies of {@code padChar} as are
* necessary to reach that length. For example,
*
*
* - {@code padStart("7", 3, '0')} returns {@code "007"}
*
- {@code padStart("2010", 3, '0')} returns {@code "2010"}
*
*
* @param string the string which should appear at the end of the result
* @param minLength the minimum length the resulting string must have. Can be
* zero or negative, in which case the input string is always returned.
* @param padChar the character to insert at the beginning of the result until
* the minimum length is reached
* @return the padded string
*/
public static String padStart(String string, int minLength, char padChar) {
checkNotNull(string); // eager for GWT.
if (string.length() >= minLength) {
return string;
}
StringBuilder sb = new StringBuilder(minLength);
for (int i = string.length(); i < minLength; i++) {
sb.append(padChar);
}
sb.append(string);
return sb.toString();
}
/**
* Returns a string, of length at least {@code minLength}, consisting of
* {@code string} appended with as many copies of {@code padChar} as are
* necessary to reach that length. For example,
*
*
* - {@code padEnd("4.", 5, '0')} returns {@code "4.000"}
*
- {@code padEnd("2010", 3, '!')} returns {@code "2010"}
*
*
* @param string the string which should appear at the beginning of the result
* @param minLength the minimum length the resulting string must have. Can be
* zero or negative, in which case the input string is always returned.
* @param padChar the character to append to the end of the result until the
* minimum length is reached
* @return the padded string
*/
public static String padEnd(String string, int minLength, char padChar) {
checkNotNull(string); // eager for GWT.
if (string.length() >= minLength) {
return string;
}
StringBuilder sb = new StringBuilder(minLength);
sb.append(string);
for (int i = string.length(); i < minLength; i++) {
sb.append(padChar);
}
return sb.toString();
}
/**
* Returns a string consisting of a specific number of concatenated copies of
* an input string. For example, {@code repeat("hey", 3)} returns the string
* {@code "heyheyhey"}.
*
* @param string any non-null string
* @param count the number of times to repeat it; a nonnegative integer
* @return a string containing {@code string} repeated {@code count} times
* (the empty string if {@code count} is zero)
* @throws IllegalArgumentException if {@code count} is negative
*/
public static String repeat(String string, int count) {
checkNotNull(string); // eager for GWT.
if (count <= 1) {
checkArgument(count >= 0, "invalid count: %s", count);
return (count == 0) ? "" : string;
}
// IF YOU MODIFY THE CODE HERE, you must update StringsRepeatBenchmark
final int len = string.length();
final long longSize = (long) len * (long) count;
final int size = (int) longSize;
if (size != longSize) {
throw new ArrayIndexOutOfBoundsException("Required array size too large: " + longSize);
}
final char[] array = new char[size];
string.getChars(0, len, array, 0);
int n;
for (n = len; n < size - n; n <<= 1) {
System.arraycopy(array, 0, array, n, n);
}
System.arraycopy(array, 0, array, n, size - n);
return new String(array);
}
}