org.apache.tools.ant.types.resources.Last Maven / Gradle / Ivy
/*
* 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
*
* https://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.Collection;
import java.util.List;
import java.util.stream.Collectors;
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 count elements of
* another ResourceCollection, a la the UNIX tail command.
* @since Ant 1.7.1
*/
public class Last extends SizeLimitCollection {
/**
* Take the last count elements.
* @return a Collection of Resources.
*/
@Override
protected Collection getCollection() {
int count = getValidCount();
ResourceCollection rc = getResourceCollection();
int size = rc.size();
int skip = Math.max(0, size - count);
List result =
rc.stream().skip(skip).collect(Collectors.toList());
int found = result.size();
if (found == count || (size < count && found == size)) {
return result;
}
//mismatch:
String msg = String.format(
"Resource collection %s reports size %d but returns %d elements.",
rc, size, found + skip);
//size was understated -> too many results; warn and continue:
if (found > count) {
log(msg, Project.MSG_WARN);
return result.subList(found - count, found);
}
//size was overstated; we missed some and are now in error-land:
throw new BuildException(msg);
}
}