proj.zoie.impl.indexing.FileDataProvider Maven / Gradle / Ivy
package proj.zoie.impl.indexing;
/**
* 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.
*/
import java.io.File;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Comparator;
import java.util.Stack;
import proj.zoie.api.DataConsumer.DataEvent;
public class FileDataProvider extends StreamDataProvider
{
private final File _dir;
private long _currentVersion = 0L;
private Stack> _stack;
private Iterator _currentIterator;
private boolean _looping;
public FileDataProvider(File dir, Comparator versionComparator)
{
super(versionComparator);
if (!dir.exists())
throw new IllegalArgumentException("dir: "+dir+" does not exist.");
_dir=dir;
_stack=new Stack>();
_looping = false;
reset();
}
public File getDir()
{
return _dir;
}
public String getZoieVersion()
{
return Long.toString(_currentVersion);
}
public String getMinZoieVersion()
{
return Long.toString(0L);
}
public String nextZoieVersion()
{
return Long.toString(_currentVersion + 1L);
}
@Override
public void reset()
{
_stack.clear();
if (_dir.isFile())
{
_currentIterator=Arrays.asList(new File[]{_dir}).iterator();
}
else
{
_currentIterator=Arrays.asList(_dir.listFiles()).iterator();
}
}
public void setLooping(boolean looping){
_looping = looping;
}
@Override
public DataEvent next() {
if(_currentIterator.hasNext())
{
File next=_currentIterator.next();
if (next.isFile())
{
// ?? hao: how to implement version++
// new DataEvent(next, _currentVersion++);
return new DataEvent(next,nextZoieVersion());
}
else
{
_stack.push(_currentIterator);
_currentIterator=Arrays.asList(next.listFiles()).iterator();
return next();
}
}
else
{
if (_stack.isEmpty())
{
if (_looping){
reset();
return next();
}
else{
return null;
}
}
else
{
_currentIterator=_stack.pop();
return next();
}
}
}
@Override
public void setStartingOffset(String version) {
throw new UnsupportedOperationException("");
}
}