106 lines
3.0 KiB
Java
106 lines
3.0 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.tomcat.util.buf;
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import java.util.Arrays;
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import java.util.Collection;
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/**
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* Utility methods to build a separated list from a given set (not
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* java.util.Set) of inputs and return that list as a string or append it to an
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* existing StringBuilder. If the given set is null or empty, an empty string
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* will be returned.
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*/
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public final class StringUtils {
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private static final String EMPTY_STRING = "";
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private StringUtils() {
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// Utility class
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}
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public static String join(String[] array) {
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if (array == null) {
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return EMPTY_STRING;
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}
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return join(Arrays.asList(array));
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}
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public static void join(String[] array, char separator, StringBuilder sb) {
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if (array == null) {
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return;
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}
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join(Arrays.asList(array), separator, sb);
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}
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public static String join(Collection<String> collection) {
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return join(collection, ',');
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}
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public static String join(Collection<String> collection, char separator) {
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// Shortcut
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if (collection == null || collection.isEmpty()) {
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return EMPTY_STRING;
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}
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StringBuilder result = new StringBuilder();
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join(collection, separator, result);
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return result.toString();
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}
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public static void join(Iterable<String> iterable, char separator, StringBuilder sb) {
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join(iterable, separator,
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new Function<String>() {@Override public String apply(String t) { return t; }}, sb);
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}
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public static <T> void join(T[] array, char separator, Function<T> function,
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StringBuilder sb) {
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if (array == null) {
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return;
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}
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join(Arrays.asList(array), separator, function, sb);
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}
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public static <T> void join(Iterable<T> iterable, char separator, Function<T> function,
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StringBuilder sb) {
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if (iterable == null) {
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return;
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}
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boolean first = true;
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for (T value : iterable) {
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if (first) {
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first = false;
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} else {
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sb.append(separator);
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}
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sb.append(function.apply(value));
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}
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}
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public interface Function<T> {
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public String apply(T t);
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}
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}
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