fiftyone.mobile.detection.entities.stream.TriePool Maven / Gradle / Ivy
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package fiftyone.mobile.detection.entities.stream;
import fiftyone.mobile.detection.IDisposable;
import fiftyone.mobile.detection.readers.TrieReader;
import java.io.IOException;
import java.util.Queue;
import java.util.concurrent.LinkedBlockingDeque;
/* *********************************************************************
* This Source Code Form is copyright of 51Degrees Mobile Experts Limited.
* Copyright 2014 51Degrees Mobile Experts Limited, 5 Charlotte Close,
* Caversham, Reading, Berkshire, United Kingdom RG4 7BY
*
* This Source Code Form is the subject of the following patent
* applications, owned by 51Degrees Mobile Experts Limited of 5 Charlotte
* Close, Caversham, Reading, Berkshire, United Kingdom RG4 7BY:
* European Patent Application No. 13192291.6; and
* United States Patent Application Nos. 14/085,223 and 14/085,301.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0.
*
* If a copy of the MPL was not distributed with this file, You can obtain
* one at http://mozilla.org/MPL/2.0/.
*
* This Source Code Form is "Incompatible With Secondary Licenses", as
* defined by the Mozilla Public License, v. 2.0.
* ********************************************************************* */
/**
* As multiple threads need to read from the Source concurrently this class
* provides a mechanism for readers to be recycled across threads and requests.
* Used by the BaseList of type T to provide multiple readers for the list.
The
* DetectorDataSet must be disposed of to ensure the readers in the pool are
* closed.
*/
public class TriePool implements IDisposable {
// List of readers available to be used.
private final Queue readers = new LinkedBlockingDeque();
// A pool of file readers to use to read data from the file.
private final TrieSource source;
/**
* Constructs a new pool of readers for the source provided.
*
**** @param source The data source for the list
*/
public TriePool(TrieSource source) {
this.source = source;
}
/**
* Returns a reader to the temp file for exclusive use. Release method must
* be called to return the reader to the pool when finished.
*
* @return Reader open and ready to read from the temp file
* @throws java.io.IOException indicates an I/O exception occurred
*/
public TrieReader getReader() throws IOException {
TrieReader reader = readers.poll();
if (reader == null) {
reader = source.createReader();
}
return reader;
}
/**
* Returns the reader to the pool to be used by another process later.
*
**** @param reader Reader open and ready to read from the temp file
*/
public void release(TrieReader reader) {
readers.add(reader);
}
@Override
public void dispose() {
source.dispose();
}
}