java.io.FileReader 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 java.io;
/**
* A specialized {@link Reader} that reads from a file in the file system.
* All read requests made by calling methods in this class are directly
* forwarded to the equivalent function of the underlying operating system.
* Since this may induce some performance penalty, in particular if many small
* read requests are made, a FileReader is often wrapped by a
* BufferedReader.
*
* @see BufferedReader
* @see FileWriter
*/
public class FileReader extends InputStreamReader {
/**
* Constructs a new FileReader on the given {@code file}.
*
* @param file
* a File to be opened for reading characters from.
* @throws FileNotFoundException
* if {@code file} does not exist.
*/
public FileReader(File file) throws FileNotFoundException {
super(new FileInputStream(file));
}
/**
* Construct a new FileReader on the given FileDescriptor {@code fd}. Since
* a previously opened FileDescriptor is passed as an argument, no
* FileNotFoundException can be thrown.
*
* @param fd
* the previously opened file descriptor.
*/
public FileReader(FileDescriptor fd) {
super(new FileInputStream(fd));
}
/**
* Construct a new FileReader on the given file named {@code filename}.
*
* @param filename
* an absolute or relative path specifying the file to open.
* @throws FileNotFoundException
* if there is no file named {@code filename}.
*/
public FileReader(String filename) throws FileNotFoundException {
super(new FileInputStream(filename));
}
}