org.apache.catalina.util.IOTools Maven / Gradle / Ivy
/*
* 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.catalina.util;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
/**
* Contains commonly needed I/O-related methods
*
* @author Dan Sandberg
*/
public class IOTools {
protected static final int DEFAULT_BUFFER_SIZE=4*1024; //4k
private IOTools() {
//Ensure non-instantiability
}
/**
* Read input from reader and write it to writer until there is no more
* input from reader.
*
* @param reader the reader to read from.
* @param writer the writer to write to.
* @param buf the char array to use as a buffer
* @throws IOException IO error
*/
public static void flow( Reader reader, Writer writer, char[] buf )
throws IOException {
int numRead;
while ( (numRead = reader.read(buf) ) >= 0) {
writer.write(buf, 0, numRead);
}
}
/**
* Read input from reader and write it to writer until there is no more
* input from reader.
*
* @param reader the reader to read from.
* @param writer the writer to write to.
* @throws IOException IO error
* @see #flow( Reader, Writer, char[] )
*/
public static void flow( Reader reader, Writer writer )
throws IOException {
char[] buf = new char[DEFAULT_BUFFER_SIZE];
flow( reader, writer, buf );
}
/**
* Read input from input stream and write it to output stream until there is
* no more input from input stream using a new buffer of the default size
* (4 KiB).
*
* @param is input stream the input stream to read from.
* @param os output stream the output stream to write to.
*
* @throws IOException If an I/O error occurs during the copy
*/
public static void flow(InputStream is, OutputStream os) throws IOException {
byte[] buf = new byte[DEFAULT_BUFFER_SIZE];
int numRead;
while ( (numRead = is.read(buf) ) >= 0) {
if (os != null) {
os.write(buf, 0, numRead);
}
}
}
/**
* Read until EOF or the buffer is filled.
*
* @param is The source to read from
* @param buf The buffer to write to
*
* @return The number of bytes read
*
* @throws IOException If an I/O error occurs during the read
*/
public static int readFully(InputStream is, byte[] buf) throws IOException {
int bytesRead = 0;
int read;
while (bytesRead < buf.length && ((read = is.read(buf, bytesRead, buf.length - bytesRead)) >= 0)) {
bytesRead += read;
}
return bytesRead;
}
}