com.google.common.base.Defaults Maven / Gradle / Ivy
/*
* Copyright (C) 2007 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 com.google.common.base;
import java.util.HashMap;
import java.util.Map;
/**
* This class provides default values for all Java types, as defined by the JLS.
*
* @author Ben Yu
*/
public final class Defaults {
private Defaults() {}
private static final Map, Object> DEFAULTS = new HashMap, Object>(16);
private static void put(Class type, T value) {
DEFAULTS.put(type, value);
}
static {
put(boolean.class, false);
put(char.class, '\0');
put(byte.class, (byte) 0);
put(short.class, (short) 0);
put(int.class, 0);
put(long.class, 0L);
put(float.class, 0f);
put(double.class, 0d);
}
/**
* Returns the default value of {@code type} as defined by JLS --- {@code 0} for numbers, {@code
* false} for {@code boolean} and {@code '\0'} for {@code char}. For non-primitive types and
* {@code void}, null is returned.
*/
@SuppressWarnings("unchecked")
public static T defaultValue(Class type) {
return (T) DEFAULTS.get(type);
}
}