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The source code
/*
* Sun Public License Notice
*
* The contents of this file are subject to the Sun Public License
* Version 1.0 (the "License"). You may not use this file except in
* compliance with the License. A copy of the License is available at
* http://www.sun.com/
*
* The Original Code is NetBeans. The Initial Developer of the Original
* Code is Sun Microsystems, Inc. Portions Copyright 1997-2000 Sun
* Microsystems, Inc. All Rights Reserved.
*/
package org.netbeans.modules.editor.java;
import java.io.EOFException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import org.netbeans.editor.ext.DataAccessor;
import org.openide.filesystems.FileObject;
import org.openide.filesystems.FileUtil;
import org.openide.filesystems.FileLock;
/**
* DataAccessor for Code Completion DB files via FileObject streams
*
* @author Martin Roskanin
*/
public class FileObjectAccessor implements DataAccessor {
FileObject fo;
InputStream inputStream;
FileOutputStream fos;
int actOff;
public FileObjectAccessor(FileObject fo) {
this.fo = fo;
}
/** Appends exactly len bytes, starting at off of the buffer pointer
* to the end of file resource.
* @param buffer the buffer from which the data is appended.
* @param off the start offset of the data in the buffer.
* @param len the number of bytes to append.
*/
public void append(byte[] buffer, int off, int len) throws IOException {
fos = new FileOutputStream(FileUtil.toFile(fo).getPath(), true);
fos.write(buffer, off, len);
fos.flush();
fos.close();
fos = null;
}
/**
* Reads exactly len bytes from this file resource into the byte
* array, starting at the current file pointer. This method reads
* repeatedly from the file until the requested number of bytes are
* read. This method blocks until the requested number of bytes are
* read, the end of the inputStream is detected, or an exception is thrown.
*
* @param buffer the buffer into which the data is read.
* @param off the start offset of the data.
* @param len the number of bytes to read.
*/
public void read(byte[] buffer, int off, int len) throws IOException {
int n = 0;
off = actOff + off;
do {
int count = this.readStream(buffer, off + n, len - n);
if (count < 0)
throw new EOFException();
n += count;
} while (n < len);
}
/** Opens DataAccessor file resource
* @param requestWrite if true, file is opened for read/write operation.
*/
public void open(boolean requestWrite) throws IOException {
if (!fo.existsExt(fo.getExt())){
resetFile();
}
}
/** Closes DataAccessor file resource */
public void close() throws IOException {
if (inputStream!=null){
inputStream.close();
}
inputStream = null;
}
/**
* Returns the current offset in this file.
*
* @return the offset from the beginning of the file, in bytes,
* at which the next read or write occurs.
*/
public long getFilePointer() throws IOException {
return actOff;
}
/** Clears the file and sets the offset to 0 */
public void resetFile() throws IOException {
FileObject folder = fo.getParent();
String name = fo.getName();
String ext = fo.getExt();
FileLock lock = fo.lock();
try {
fo.delete(lock);
} finally {
lock.releaseLock();
}
fo = folder.createData(name, ext);
actOff = 0;
}
/**
* Sets the file-pointer offset, measured from the beginning of this
* file, at which the next read or write occurs.
*/
public void seek(long pos) throws IOException {
actOff = (int)pos;
}
/** Reads up to len bytes of data from this file resource into an array of bytes.
* @param buffer the buffer into which the data is read.
* @param off the start offset of the data.
* @param len the maximum number of bytes read.
*/
private int readStream(byte[] buffer, int off, int len) throws IOException {
int read = getStream(off).read(buffer,0,len);
actOff += read;
return read;
}
/** Gets InputStream prepared for reading from off offset position*/
private InputStream getStream(int off) throws IOException {
if(inputStream == null) {
inputStream = fo.getInputStream();
inputStream.skip(off);
} else {
if(off >= actOff) {
inputStream.skip(off-actOff);
} else {
inputStream.close();
inputStream = fo.getInputStream();
inputStream.skip(off);
}
}
actOff = off;
return inputStream;
}
public int getFileLength() {
return (int)fo.getSize();
}
public String toString() {
return fo.toString();
}
}
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