104 lines
3.4 KiB
Java
104 lines
3.4 KiB
Java
/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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 android.text;
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public class TextUtils {
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private TextUtils() { /* cannot be instantiated */ }
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/**
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* Returns true if the string is null or 0-length.
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* @param str the string to be examined
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* @return true if str is null or zero length
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*/
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public static boolean isEmpty(CharSequence str) {
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return (str == null || str.length() == 0);
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}
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/**
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* Returns true if a and b are equal, including if they are both null.
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* <p><i>Note: In platform versions 1.1 and earlier, this method only worked well if
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* both the arguments were instances of String.</i></p>
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* @param a first CharSequence to check
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* @param b second CharSequence to check
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* @return true if a and b are equal
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*/
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public static boolean equals(CharSequence a, CharSequence b) {
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if (a == b) return true;
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int length;
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if (a != null && b != null && (length = a.length()) == b.length()) {
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if (a instanceof String && b instanceof String) {
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return a.equals(b);
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}
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for (int i = 0; i < length; i++) {
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if (a.charAt(i) != b.charAt(i)) return false;
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}
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return true;
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}
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return false;
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}
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/**
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* Returns list of multiple {@link CharSequence} joined into a single
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* {@link CharSequence} separated by localized delimiter such as ", ".
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*
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* @hide
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*/
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public static CharSequence join(Iterable<CharSequence> list) {
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final CharSequence delimiter = ", ";
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return join(delimiter, list);
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}
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/**
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* Returns a string containing the tokens joined by delimiters.
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* @param tokens an array objects to be joined. Strings will be formed from
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* the objects by calling object.toString().
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*/
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public static String join(CharSequence delimiter, Object[] tokens) {
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StringBuilder sb = new StringBuilder();
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boolean firstTime = true;
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for (Object token: tokens) {
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if (firstTime) {
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firstTime = false;
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} else {
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sb.append(delimiter);
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}
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sb.append(token);
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}
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return sb.toString();
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}
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/**
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* Returns a string containing the tokens joined by delimiters.
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* @param tokens an array objects to be joined. Strings will be formed from
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* the objects by calling object.toString().
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*/
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public static String join(CharSequence delimiter, Iterable<?> tokens) {
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StringBuilder sb = new StringBuilder();
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boolean firstTime = true;
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for (Object token: tokens) {
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if (firstTime) {
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firstTime = false;
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} else {
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sb.append(delimiter);
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}
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sb.append(token);
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}
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return sb.toString();
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}
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}
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