org.opencms.util.CmsCollectionsGenericWrapper Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.util;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.map.LRUMap;
import org.apache.commons.collections.map.LazyMap;
/**
* Provides Map wrapping utility functions for Java generics.
*
* @since 8.0.0
*/
public final class CmsCollectionsGenericWrapper {
/**
* Hides the public constructor.
*/
private CmsCollectionsGenericWrapper() {
// empty
}
/**
* Provides a wrapper to access the {@link LazyMap} functionality that avoids warnings with Java 1.5 generic code.
*
* @param the type of keys maintained by the returned map
* @param the type of mapped values
* @param T the transformer to use for the Lazy Map
*
* @return a {@link LazyMap} of the required generic type
*/
public static Map createLazyMap(Transformer T) {
return LazyMap.decorate(new HashMap(), T);
}
/**
* Provides a wrapper to create a {@link LRUMap} that avoids warnings with Java 1.5 generic code.
*
* @param the type of keys maintained by the returned map
* @param the type of mapped values
*
* @return a {@link LRUMap} of the required generic type
*/
@SuppressWarnings("unchecked")
public static Map createLRUMap() {
return new LRUMap();
}
/**
* Provides a wrapper to create a {@link LRUMap} with the given size that avoids warnings with Java 1.5 generic code.
*
* @param the type of keys maintained by the returned map
* @param the type of mapped values
* @param size the initial size of the created Map
*
* @return a {@link LRUMap} with the given size of the required generic type
*/
@SuppressWarnings("unchecked")
public static Map createLRUMap(int size) {
return new LRUMap(size);
}
/**
* Provides a wrapper to convert an enumeration that avoids warnings with Java 1.5 generic code.
*
* @param the type of the returned enumeration elements
* @param enumeration the enumeration to be converted
*
* @return a {@link Enumeration} with the required generic type
*/
@SuppressWarnings("unchecked")
public static Enumeration enumeration(Enumeration enumeration) {
return (Enumeration)enumeration;
}
/**
* Provides a wrapper to convert an object into a list that avoids warnings with Java 1.5 generic code.
*
* @param the type of the returned list elements
* @param o the object to be converted
*
* @return a {@link List} with the required generic type
*/
@SuppressWarnings("unchecked")
public static List list(Object o) {
return (List)o;
}
/**
* Provides a wrapper to convert an object into a map that avoids warnings with Java 1.5 generic code.
*
* @param the type of keys maintained by the returned map
* @param the type of mapped values
* @param o the object to be converted
*
* @return a {@link Map} of the required generic type
*/
@SuppressWarnings("unchecked")
public static Map map(Object o) {
return (Map)o;
}
}