robtimus commented on a change in pull request #89: Added TeeReader. URL: https://github.com/apache/commons-io/pull/89#discussion_r310347002
########## File path: src/main/java/org/apache/commons/io/input/TeeReader.java ########## @@ -0,0 +1,180 @@ +/* + * 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.commons.io.input; + +import static org.apache.commons.io.IOUtils.EOF; + +import java.io.IOException; +import java.io.Reader; +import java.io.Writer; +import java.nio.CharBuffer; + +/** + * Reader proxy that transparently writes a copy of all characters read + * from the proxied reader to a given Reader. Using {@link #skip(long)} + * or {@link #mark(int)}/{@link #reset()} on the reader will result on some + * characters from the reader being skipped or duplicated in the writer. + * <p> + * The proxied reader is closed when the {@link #close()} method is + * called on this proxy. It is configurable whether the associated writer + * will also closed. + * + * @since 2.7 + */ +public class TeeReader extends ProxyReader { + + /** + * The writer that will receive a copy of all characters read from the + * proxied reader. + */ + private final Writer branch; + + /** + * Flag for closing also the associated writer when this + * reader is closed. + */ + private final boolean closeBranch; + + /** + * Creates a TeeReader that proxies the given {@link Reader} + * and copies all read characters to the given {@link Writer}. The given + * writer will not be closed when this reader gets closed. + * + * @param input reader to be proxied + * @param branch writer that will receive a copy of all characters read + */ + public TeeReader(final Reader input, final Writer branch) { + this(input, branch, false); + } + + /** + * Creates a TeeReader that proxies the given {@link Reader} + * and copies all read characters to the given {@link Writer}. The given + * writer will be closed when this reader gets closed if the + * closeBranch parameter is {@code true}. + * + * @param input reader to be proxied + * @param branch writer that will receive a copy of all characters read + * @param closeBranch flag for closing also the writer when this + * reader is closed + */ + public TeeReader( + final Reader input, final Writer branch, final boolean closeBranch) { + super(input); + this.branch = branch; + this.closeBranch = closeBranch; + } + + /** + * Closes the proxied reader and, if so configured, the associated + * writer. An exception thrown from the reader will not prevent + * closing of the writer. + * + * @throws IOException if either the reader or writer could not be closed + */ + @Override + public void close() throws IOException { + try { + super.close(); + } finally { + if (closeBranch) { + branch.close(); + } + } + } + + /** + * Reads a single chracter from the proxied reader and writes it to + * the associated writer. + * + * @return next character from the reader, or -1 if the reader has ended + * @throws IOException if the reader could not be read (or written) + */ + @Override + public int read() throws IOException { + final int ch = super.read(); + if (ch != EOF) { + branch.write(ch); + } + return ch; + } + + /** + * Reads characters from the proxied reader and writes the read characters + * to the associated writer. + * + * @param chr character buffer + * @param st start offset within the buffer + * @param end maximum number of characters to read + * @return number of characters read, or -1 if the reader has ended + * @throws IOException if the reader could not be read (or written) + */ + @Override + public int read(final char[] chr, final int st, final int end) throws IOException { + final int n = super.read(chr, st, end); + if (n != -1) { + branch.write(chr, st, n); Review comment: Fixed, also in TeeInputStream where I copied the text from. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
