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