org.apache.thrift.transport.TSimpleFileTransport Maven / Gradle / Ivy
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/*
* 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.
*/
package org.apache.thrift.transport;
import java.io.IOException;
import java.io.RandomAccessFile;
import org.apache.thrift.TConfiguration;
/** Basic file support for the TTransport interface */
public final class TSimpleFileTransport extends TEndpointTransport {
private RandomAccessFile file = null;
private final boolean readable;
private final boolean writable;
private final String path_;
/**
* Create a transport backed by a simple file
*
* @param path the path to the file to open/create
* @param read true to support read operations
* @param write true to support write operations
* @param openFile true to open the file on construction
* @throws TTransportException if file open fails
*/
public TSimpleFileTransport(String path, boolean read, boolean write, boolean openFile)
throws TTransportException {
this(new TConfiguration(), path, read, write, openFile);
}
/**
* Create a transport backed by a simple file
*
* @param config
* @param path the path to the file to open/create
* @param read true to support read operations
* @param write true to support write operations
* @param openFile true to open the file on construction
* @throws TTransportException if file open fails
*/
public TSimpleFileTransport(
TConfiguration config, String path, boolean read, boolean write, boolean openFile)
throws TTransportException {
super(config);
if (path.length() <= 0) {
throw new TTransportException("No path specified");
}
if (!read && !write) {
throw new TTransportException("Neither READ nor WRITE specified");
}
readable = read;
writable = write;
path_ = path;
if (openFile) {
open();
}
}
/**
* Create a transport backed by a simple file Implicitly opens file to conform to C++ behavior.
*
* @param path the path to the file to open/create
* @param read true to support read operations
* @param write true to support write operations
* @throws TTransportException if file open fails
*/
public TSimpleFileTransport(String path, boolean read, boolean write) throws TTransportException {
this(path, read, write, true);
}
/**
* Create a transport backed by a simple read only disk file (implicitly opens file)
*
* @param path the path to the file to open/create
* @throws TTransportException if file open fails
*/
public TSimpleFileTransport(String path) throws TTransportException {
this(path, true, false, true);
}
/**
* Test file status
*
* @return true if open, otherwise false
*/
@Override
public boolean isOpen() {
return (file != null);
}
/**
* Open file if not previously opened.
*
* @throws TTransportException if open fails
*/
@Override
public void open() throws TTransportException {
if (file == null) {
try {
String access = "r"; // RandomAccessFile objects must be readable
if (writable) {
access += "w";
}
file = new RandomAccessFile(path_, access);
} catch (IOException ioe) {
file = null;
throw new TTransportException(ioe.getMessage());
}
}
}
/** Close file, subsequent read/write activity will throw exceptions */
@Override
public void close() {
if (file != null) {
try {
file.close();
} catch (Exception e) {
// Nothing to do
}
file = null;
}
}
/**
* Read up to len many bytes into buf at offset
*
* @param buf houses bytes read
* @param off offset into buff to begin writing to
* @param len maximum number of bytes to read
* @return number of bytes actually read
* @throws TTransportException on read failure
*/
@Override
public int read(byte[] buf, int off, int len) throws TTransportException {
if (!readable) {
throw new TTransportException("Read operation on write only file");
}
checkReadBytesAvailable(len);
int iBytesRead = 0;
try {
iBytesRead = file.read(buf, off, len);
} catch (IOException ioe) {
file = null;
throw new TTransportException(ioe.getMessage());
}
return iBytesRead;
}
/**
* Write len many bytes from buff starting at offset
*
* @param buf buffer containing bytes to write
* @param off offset into buffer to begin writing from
* @param len number of bytes to write
* @throws TTransportException on write failure
*/
@Override
public void write(byte[] buf, int off, int len) throws TTransportException {
try {
file.write(buf, off, len);
} catch (IOException ioe) {
file = null;
throw new TTransportException(ioe.getMessage());
}
}
/**
* Move file pointer to specified offset, new read/write calls will act here
*
* @param offset bytes from beginning of file to move pointer to
* @throws TTransportException is seek fails
*/
public void seek(long offset) throws TTransportException {
try {
file.seek(offset);
} catch (IOException ex) {
throw new TTransportException(ex.getMessage());
}
}
/**
* Return the length of the file in bytes
*
* @return length of the file in bytes
* @throws TTransportException if file access fails
*/
public long length() throws TTransportException {
try {
return file.length();
} catch (IOException ex) {
throw new TTransportException(ex.getMessage());
}
}
/**
* Return current file pointer position in bytes from beginning of file
*
* @return file pointer position
* @throws TTransportException if file access fails
*/
public long getFilePointer() throws TTransportException {
try {
return file.getFilePointer();
} catch (IOException ex) {
throw new TTransportException(ex.getMessage());
}
}
}