/*
* NOTE: This copyright does *not* cover user programs that use Hyperic
* program services by normal system calls through the application
* program interfaces provided as part of the Hyperic Plug-in Development
* Kit or the Hyperic Client Development Kit - this is merely considered
* normal use of the program, and does *not* fall under the heading of
* "derived work".
*
* Copyright (C) [2004-2013], VMware, Inc.
* This file is part of Hyperic.
*
* Hyperic is free software; you can redistribute it and/or modify
* it under the terms version 2 of the GNU 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 General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*/
package org.hyperic.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public abstract class Transformer<T, R> {
public Set<R> transformToSet(Collection<T> c) {
if (c == null || c.isEmpty()) {
return Collections.emptySet();
}
final Set<R> rtn = new HashSet<R>();
transformAndAddToCollection(c, rtn);
return rtn;
}
public List<R> transformToList(Collection<T> c) {
if (c == null || c.isEmpty()) {
return Collections.emptyList();
}
final List<R> rtn = new ArrayList<R>();
transformAndAddToCollection(c, rtn);
return rtn;
}
public List<R> transform(Collection<T> c) {
if (c == null || c.isEmpty()) {
return Collections.emptyList();
}
final List<R> rtn = new ArrayList<R>(c.size());
for (T obj : c) {
R t = transform(obj);
if (t != null) {
rtn.add(t);
}
}
return rtn;
}
public abstract R transform(T obj);
private void transformAndAddToCollection(Collection<T> in, Collection<R> out) {
for (T obj : in) {
R t = transform(obj);
if (t != null) {
out.add(t);
}
}
}
}