/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.tools.ant.types.resources;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
/**
* ResourceCollection that contains the last <code>count</code> elements of
* another ResourceCollection, a la the UNIX tail command.
* @since Ant 1.7.1
*/
public class Last extends SizeLimitCollection {
/**
* Take the last <code>count</code> elements.
* @return a Collection of Resources.
*/
protected Collection<Resource> getCollection() {
int count = getValidCount();
ResourceCollection rc = getResourceCollection();
int i = count;
Iterator<Resource> iter = rc.iterator();
int size = rc.size();
for (; i < size; i++) {
iter.next();
}
List<Resource> al = new ArrayList<Resource>(count);
for (; iter.hasNext(); i++) {
al.add(iter.next());
}
int found = al.size();
if (found == count || (size < count && found == size)) {
return al;
}
//mismatch:
String msg = "Resource collection " + rc + " reports size " + size
+ " but returns " + i + " elements.";
//size was understated -> too many results; warn and continue:
if (found > count) {
log(msg, Project.MSG_WARN);
return al.subList(found - count, found);
}
//size was overstated; we missed some and are now in error-land:
throw new BuildException(msg);
}
}