From: David ‘Bombe’ Roden Date: Mon, 6 Jan 2014 12:12:19 +0000 (+0100) Subject: Add writer that squelches duplicate lines. X-Git-Url: https://git.pterodactylus.net/?a=commitdiff_plain;h=6e50defe7a95a4658bc0ce68eab5ca79361552d5;p=xudocci.git Add writer that squelches duplicate lines. --- diff --git a/src/main/java/net/pterodactylus/xdcc/ui/stdin/DuplicateLineSuppressingWriter.java b/src/main/java/net/pterodactylus/xdcc/ui/stdin/DuplicateLineSuppressingWriter.java new file mode 100644 index 0000000..dfd9ed5 --- /dev/null +++ b/src/main/java/net/pterodactylus/xdcc/ui/stdin/DuplicateLineSuppressingWriter.java @@ -0,0 +1,119 @@ +/* + * XdccDownloader - DuplicateLineSuppressingWriter.java - Copyright © 2013 David Roden + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +package net.pterodactylus.xdcc.ui.stdin; + +import java.io.IOException; +import java.io.Writer; + +/** + * {@link Writer} implementation that suppreses multiple identical lines written to it. + * + * @author David ‘Bombe’ Roden + */ +public class DuplicateLineSuppressingWriter extends Writer { + + private final Writer writer; + private String lastLine; + private final StringBuilder currentLine = new StringBuilder(); + + public DuplicateLineSuppressingWriter(Writer writer) { + this.writer = writer; + } + + @Override + public void write(char[] cbuf) throws IOException { + write(cbuf, 0, cbuf.length); + } + + @Override + public void write(String str) throws IOException { + write(str, 0, str.length()); + } + + @Override + public Writer append(CharSequence csq) throws IOException { + write(String.valueOf(csq)); + return this; + } + + @Override + public Writer append(CharSequence csq, int start, int end) throws IOException { + write(String.valueOf(csq).substring(start, end)); + return this; + } + + @Override + public Writer append(char c) throws IOException { + write(c); + return this; + } + + @Override + public void flush() throws IOException { + writer.flush(); + } + + @Override + public void close() throws IOException { + writer.close(); + } + + @Override + public void write(int c) throws IOException { + currentLine.append((char) c); + writeCollectedLines(); + } + + @Override + public void write(char[] cbuf, int off, int len) throws IOException { + currentLine.append(cbuf, off, len); + writeCollectedLines(); + } + + @Override + public void write(String str, int off, int len) throws IOException { + currentLine.append(str, off, len); + writeCollectedLines(); + } + + private void writeCollectedLines() throws IOException { + while (currentLineContainsLineBreak()) { + String nextLine = cutNextLine(); + maybeWriteNextLine(nextLine); + } + } + + private void maybeWriteNextLine(String nextLine) throws IOException { + if (!nextLine.equals(lastLine)) { + writer.write(nextLine); + lastLine = nextLine; + } + } + + private String cutNextLine() { + int indexOfLineBreak = currentLine.indexOf("\n"); + String nextLine = currentLine.substring(0, indexOfLineBreak + 1); + currentLine.delete(0, indexOfLineBreak + 1); + return nextLine; + } + + private boolean currentLineContainsLineBreak() { + return currentLine.indexOf("\n") > -1; + } + +} diff --git a/src/test/java/net/pterodactylus/xdcc/ui/stdin/DuplicateLineSuppressingWriterTest.java b/src/test/java/net/pterodactylus/xdcc/ui/stdin/DuplicateLineSuppressingWriterTest.java new file mode 100644 index 0000000..3465abb --- /dev/null +++ b/src/test/java/net/pterodactylus/xdcc/ui/stdin/DuplicateLineSuppressingWriterTest.java @@ -0,0 +1,69 @@ +/* + * XdccDownloader - DuplicateLineSuppressingWriterTest.java - Copyright © 2013 David Roden + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +package net.pterodactylus.xdcc.ui.stdin; + +import static org.hamcrest.MatcherAssert.assertThat; +import static org.hamcrest.Matchers.is; + +import java.io.IOException; +import java.io.StringWriter; + +import org.junit.Test; + +/** + * Unit test for {@link DuplicateLineSuppressingWriter}. + * + * @author David ‘Bombe’ Roden + */ +public class DuplicateLineSuppressingWriterTest { + + private final StringWriter stringWriter = new StringWriter(); + private final DuplicateLineSuppressingWriter duplicateLineSuppressingWriter = new DuplicateLineSuppressingWriter(stringWriter); + + @Test + public void theFirstLineIsWrittenImmediately() throws IOException { + duplicateLineSuppressingWriter.write("First Line.\n"); + assertThat(stringWriter.toString(), is("First Line.\n")); + } + + @Test + public void twoDifferentLinesAreWrittenOut() throws IOException { + duplicateLineSuppressingWriter.write("First Line.\n"); + duplicateLineSuppressingWriter.write("Second Line.\n"); + assertThat(stringWriter.toString(), is("First Line.\nSecond Line.\n")); + } + + @Test + public void twoEqualLinesAreOnlyWrittenOnce() throws IOException { + duplicateLineSuppressingWriter.write("First Line.\n"); + duplicateLineSuppressingWriter.write("First Line.\n"); + assertThat(stringWriter.toString(), is("First Line.\n")); + } + + @Test + public void multipleLinesAreSuppressed() throws IOException { + duplicateLineSuppressingWriter.write("First Line.\n"); + duplicateLineSuppressingWriter.write("Second Line.\n"); + duplicateLineSuppressingWriter.write("Second Line.\n"); + duplicateLineSuppressingWriter.write("Second Line.\n"); + duplicateLineSuppressingWriter.write("First Line.\n"); + duplicateLineSuppressingWriter.write("First Line.\n"); + assertThat(stringWriter.toString(), is("First Line.\nSecond Line.\nFirst Line.\n")); + } + +}