Java tutorial
/* * Copyright 2004 The Apache Software Foundation * * Licensed 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. */ //based on Apache technology http://www.apache.org import java.io.IOException; import java.io.LineNumberReader; import java.io.Reader; import java.util.List; public class Diff { public static void readersAsText(Reader r1, String name1, Reader r2, String name2, List diffs) throws IOException { LineNumberReader reader1 = new LineNumberReader(r1); LineNumberReader reader2 = new LineNumberReader(r2); String line1 = reader1.readLine(); String line2 = reader2.readLine(); while (line1 != null && line2 != null) { if (!line1.equals(line2)) { diffs.add("File \"" + name1 + "\" and file \"" + name2 + "\" differ at line " + reader1.getLineNumber() + ":" + "\n" + line1 + "\n" + line2); break; } line1 = reader1.readLine(); line2 = reader2.readLine(); } if (line1 == null && line2 != null) diffs.add("File \"" + name2 + "\" has extra lines at line " + reader2.getLineNumber() + ":\n" + line2); if (line1 != null && line2 == null) diffs.add("File \"" + name1 + "\" has extra lines at line " + reader1.getLineNumber() + ":\n" + line1); } }