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// Copyright 2014 Google Inc. All rights reserved.
//
// 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.google.devtools.build.lib.util;
import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
/**
* Various utility methods operating on strings.
*/
public class StringUtil {
/**
* Creates a comma-separated list of words as in English.
*
* <p>Example: ["a", "b", "c"] -> "a, b or c".
*/
public static String joinEnglishList(Iterable<?> choices) {
return joinEnglishList(choices, "or", "");
}
/**
* Creates a comma-separated list of words as in English with the given last-separator.
*
* <p>Example with lastSeparator="then": ["a", "b", "c"] -> "a, b then c".
*/
public static String joinEnglishList(Iterable<?> choices, String lastSeparator) {
return joinEnglishList(choices, lastSeparator, "");
}
/**
* Creates a comma-separated list of words as in English with the given last-separator and quotes.
*
* <p>Example with lastSeparator="then", quote="'": ["a", "b", "c"] -> "'a', 'b' then 'c'".
*/
public static String joinEnglishList(Iterable<?> choices, String lastSeparator, String quote) {
StringBuilder buf = new StringBuilder();
for (Iterator<?> ii = choices.iterator(); ii.hasNext(); ) {
Object choice = ii.next();
if (buf.length() > 0) {
buf.append(ii.hasNext() ? "," : " " + lastSeparator);
buf.append(" ");
}
buf.append(quote).append(choice).append(quote);
}
return buf.length() == 0 ? "nothing" : buf.toString();
}
/**
* Split a single space-separated string into a List of values.
*
* <p>Individual values are canonicalized such that within and
* across calls to this method, equal values point to the same
* object.
*
* <p>If the input is null, return an empty list.
*
* @param in space-separated list of values, eg "value1 value2".
*/
public static List<String> splitAndInternString(String in) {
List<String> result = new ArrayList<>();
if (in == null) {
return result;
}
for (String val : Splitter.on(' ').omitEmptyStrings().split(in)) {
// Note that splitter returns a substring(), effectively
// retaining the entire "in" String. Make an explicit copy here
// to avoid that memory pitfall. Further, because there may be
// many concurrent submissions that touch the same files,
// attempt to use a single reference for equal strings via the
// deduplicator.
result.add(StringCanonicalizer.intern(new String(val)));
}
return result;
}
/**
* Lists items up to a given limit, then prints how many were omitted.
*/
public static StringBuilder listItemsWithLimit(StringBuilder appendTo, int limit,
Collection<?> items) {
Preconditions.checkState(limit > 0);
Joiner.on(", ").appendTo(appendTo, Iterables.limit(items, limit));
if (items.size() > limit) {
appendTo.append(" ...(omitting ")
.append(items.size() - limit)
.append(" more item(s))");
}
return appendTo;
}
/**
* Returns the ordinal representation of the number.
*/
public static String ordinal(int number) {
switch (number) {
case 1:
return "1st";
case 2:
return "2nd";
case 3:
return "3rd";
default:
return number + "th";
}
}
/**
* Appends a prefix and a suffix to each of the Strings.
*/
public static Iterable<String> append(Iterable<String> values, final String prefix,
final String suffix) {
return Iterables.transform(values, new Function<String, String>() {
@Override
public String apply(String input) {
return prefix + input + suffix;
}
});
}
/**
* Indents the specified string by the given number of characters.
*
* <p>The beginning of the string before the first newline is not indented.
*/
public static String indent(String input, int depth) {
StringBuilder prefix = new StringBuilder();
prefix.append("\n");
for (int i = 0; i < depth; i++) {
prefix.append(" ");
}
return input.replace("\n", prefix);
}
/**
* Strips a suffix from a string. If the string does not end with the suffix, returns null.
*/
public static String stripSuffix(String input, String suffix) {
return input.endsWith(suffix)
? input.substring(0, input.length() - suffix.length())
: null;
}
/**
* Capitalizes the first character of a string.
*/
public static String capitalize(String input) {
if (input.isEmpty()) {
return input;
}
char first = input.charAt(0);
char capitalized = Character.toUpperCase(first);
return first == capitalized ? input : capitalized + input.substring(1);
}
}
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