/**
* Copyright 2009 Google Inc.
*
* 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 org.waveprotocol.wave.model.util;
/**
* Utilities related to the document-based value classes
*
* @author anorth@google.com (Alex North)
*/
public final class ValueUtils {
/**
* @return true iff a and b are both null or are equal
*/
public static <T> boolean equal(T a, T b) {
return (a == null) ? (b == null) : a.equals(b);
}
/**
* @return true iff a and b are not both null and are not equal
*/
public static <T> boolean notEqual(T a, T b) {
return (a == null) ? (b != null) : !a.equals(b);
}
/**
* @return {@code value} if it is not null, {@code def} otherwise
*/
public static <T> T valueOrDefault(T value, T def) {
return value != null ? value : def;
}
/**
* Returns the first {@code size} characters of the given string
*/
public static String abbrev(String longString, int size) {
if (longString == null) {
return null;
}
return longString.length() <= size ? longString
: new String(longString.substring(0, size));
}
}