org.opencastproject.util.ChunkedFileInputStream Maven / Gradle / Ivy
/*
* Licensed to The Apereo Foundation under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
*
* The Apereo Foundation licenses this file to you under the Educational
* Community 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://opensource.org/licenses/ecl2.txt
*
* 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.opencastproject.util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
/**
* input stream to get only a part of a file
*
*/
public class ChunkedFileInputStream extends FileInputStream {
/**
* starting offset
*/
private long offset;
/**
* the current offset
*/
private long currentOffset;
/**
* ending offset
*/
private long endOffset;
private static final Logger logger = LoggerFactory.getLogger(ChunkedFileInputStream.class);
/**
* constructor
*
* @param name the name of the file
* @throws FileNotFoundException if the file was not found
*/
public ChunkedFileInputStream(String name) throws FileNotFoundException {
this(name != null ? new File(name) : null, 0, 0);
}
/**
* constructor
*
* @param file the file to load
* @param offset the starting offset
* @param endOffset the ending offset
* @throws FileNotFoundException if the requested file was not found
*/
public ChunkedFileInputStream(File file, long offset, long endOffset)
throws FileNotFoundException {
super(file);
this.offset = offset;
this.currentOffset = offset;
this.endOffset = endOffset == 0 ? file.length() : endOffset;
if (offset != 0) {
logger.debug("skipping first {} bytes", offset);
try {
this.skip(offset);
} catch (IOException e) {
logger.error(e.getMessage(), e);
}
}
}
/**
* read the next byte
*
* @return the next byte or -1 if the expected offset has been reached
*/
public int read() throws IOException {
this.currentOffset++;
if (currentOffset > endOffset) {
return -1;
}
return super.read();
}
/**
* get the ending offset
*
* @return the ending offset
*/
public long getEndOffset() {
return endOffset;
}
/**
* set the ending offset
*
* @param endOffset the ending offset
*/
public void setEndOffset(long endOffset) {
this.endOffset = endOffset;
}
/***
* get the starting offset
*
* @return the starting offset
*/
public long getOffset() {
return offset;
}
/**
* set the starting offset
*
* @param offset the starting offset
*/
public void setOffset(long offset) {
this.offset = offset;
}
}