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/*
* Copyright (c) 2007, 2011-2013, 2015, 2016 Eike Stepper (Loehne, Germany) and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Eike Stepper - initial API and implementation
* Christian W. Damus (CEA LIST) - bug 418454
*/
package org.eclipse.net4j.util;
import org.eclipse.net4j.util.collection.Closeable;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Map;
/**
* Various static helper methods.
*
* @author Eike Stepper
*/
public final class ObjectUtil
{
private ObjectUtil()
{
}
/**
* @since 3.6
*/
public static boolean never()
{
return false;
}
public static boolean equals(Object o1, Object o2)
{
if (o1 == null)
{
return o2 == null;
}
return o1.equals(o2);
}
public static int hashCode(Object o)
{
if (o == null)
{
return 0;
}
return o.hashCode();
}
/**
* A collision-free hash code for small sets (<=4) of small, positive integers (<=128)
*
* @since 3.2
*/
public static int hashCode(int... values)
{
int hash = 0;
for (int i = 0; i < values.length; i++)
{
hash += values[i];
hash = (hash << 7) - hash;
}
return hash;
}
public static int hashCode(long num)
{
return (int)(num >> 32) ^ (int)(num & 0xffffffff);
}
@SuppressWarnings("unchecked")
public static <T> T[] appendtoArray(T[] array, T... elements)
{
T[] result = (T[])Array.newInstance(array.getClass().getComponentType(), array.length + elements.length);
System.arraycopy(array, 0, result, 0, array.length);
System.arraycopy(elements, 0, result, array.length, elements.length);
return result;
}
/**
* @since 3.1
*/
public static <T> boolean isEmpty(T[] array)
{
return array == null || array.length == 0;
}
/**
* @since 3.1
*/
public static <T extends Map<?, ?>> boolean isEmpty(Map<?, ?> map)
{
return map == null || map.isEmpty();
}
/**
* @since 3.1
*/
public static <T extends Collection<?>> boolean isEmpty(Collection<?> collection)
{
return collection == null || collection.isEmpty();
}
/**
* @since 3.1
*/
public static boolean isEmpty(String string)
{
return string == null || string.length() == 0;
}
/**
* @since 3.3
*/
public static Exception close(Object object)
{
try
{
if (object instanceof Closeable)
{
Closeable closeable = (Closeable)object;
closeable.close();
}
else if (object instanceof java.io.Closeable)
{
java.io.Closeable closeable = (java.io.Closeable)object;
closeable.close();
}
}
catch (Exception ex)
{
return ex;
}
return null;
}
/**
* @since 3.3
*/
public static <T> T notNull(T object)
{
if (object == null)
{
throw new NullPointerException();
}
return object;
}
/**
* Attempts to cast an {@code object} as an instance of the given {@code type}.
*
* @param object an object to cast to some {@code type}
* @param type the type to cast the {@code object} to
* @return the {@code object} or {@code null} if it is not of the required {@code type}
*
* @since 3.4
*/
public static <T> T tryCast(Object object, Class<T> type)
{
if (type.isInstance(object))
{
return type.cast(object);
}
return null;
}
}
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