/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Various help for handling collections.
*
* @author Gavin King
* @author Steve Ebersole
*/
public final class CollectionHelper {
public static final List EMPTY_LIST = Collections.unmodifiableList( new ArrayList(0) );
public static final Collection EMPTY_COLLECTION = Collections.unmodifiableCollection( new ArrayList(0) );
public static final Map EMPTY_MAP = Collections.unmodifiableMap( new HashMap(0) );
private CollectionHelper() {
}
/**
* Build a properly sized map, especially handling load size and load factor to prevent immediate resizing.
* <p/>
* Especially helpful for copy map contents.
*
* @param size The size to make the map.
* @return The sized map.
*/
public static Map mapOfSize(int size) {
final int currentSize = (int) (size / 0.75f);
return new HashMap( Math.max( currentSize+ 1, 16), 0.75f );
}
}
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