ohrstrom@1504: /*
ohrstrom@1504:  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
ohrstrom@1504:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ohrstrom@1504:  *
ohrstrom@1504:  * This code is free software; you can redistribute it and/or modify it
ohrstrom@1504:  * under the terms of the GNU General Public License version 2 only, as
ohrstrom@1504:  * published by the Free Software Foundation.  Oracle designates this
ohrstrom@1504:  * particular file as subject to the "Classpath" exception as provided
ohrstrom@1504:  * by Oracle in the LICENSE file that accompanied this code.
ohrstrom@1504:  *
ohrstrom@1504:  * This code is distributed in the hope that it will be useful, but WITHOUT
ohrstrom@1504:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ohrstrom@1504:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ohrstrom@1504:  * version 2 for more details (a copy is included in the LICENSE file that
ohrstrom@1504:  * accompanied this code).
ohrstrom@1504:  *
ohrstrom@1504:  * You should have received a copy of the GNU General Public License version
ohrstrom@1504:  * 2 along with this work; if not, write to the Free Software Foundation,
ohrstrom@1504:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ohrstrom@1504:  *
ohrstrom@1504:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohrstrom@1504:  * or visit www.oracle.com if you need additional information or have any
ohrstrom@1504:  * questions.
ohrstrom@1504:  */
ohrstrom@1504: package com.sun.tools.sjavac.comp;
ohrstrom@1504: 
ohrstrom@1504: import java.io.*;
ohrstrom@1504: import javax.tools.JavaFileObject;
ohrstrom@1504: 
ohrstrom@1504: /**
ohrstrom@1504:  * The SmartWriter will cache the written data and when the writer is closed,
ohrstrom@1504:  * then it will compare the cached data with the old_content string.
ohrstrom@1504:  * If different, then it will write all the new content to the file.
ohrstrom@1504:  * If not, the file is not touched.
ohrstrom@1504:  *
ohrstrom@1504:  *  <p><b>This is NOT part of any supported API.
ohrstrom@1504:  * If you write code that depends on this, you do so at your own
ohrstrom@1504:  * risk.  This code and its internal interfaces are subject to change
ohrstrom@1504:  * or deletion without notice.</b></p>
ohrstrom@1504:  */
ohrstrom@1504: public class SmartWriter extends Writer {
ohrstrom@1504: 
ohrstrom@1504:     String name;
ohrstrom@1504:     JavaFileObject file;
ohrstrom@1504:     String oldContent;
ohrstrom@1504:     StringWriter newContent = new StringWriter();
ohrstrom@1504:     PrintWriter stdout;
ohrstrom@1504:     boolean closed;
ohrstrom@1504:     public SmartWriter(JavaFileObject f, String s, String n, PrintWriter pw) {
ohrstrom@1504:         name = n;
ohrstrom@1504:         file = f;
ohrstrom@1504:         oldContent = s;
ohrstrom@1504:         newContent = new StringWriter();
ohrstrom@1504:         stdout = pw;
ohrstrom@1504:         closed = false;
ohrstrom@1504:     }
ohrstrom@1504: 
ohrstrom@1504:     public void write(char[] chars, int i, int i1)
ohrstrom@1504:     {
ohrstrom@1504:         newContent.write(chars, i, i1);
ohrstrom@1504:     }
ohrstrom@1504: 
ohrstrom@1504:     public void close() throws IOException {
ohrstrom@1504:         if (closed) return;
ohrstrom@1504:         closed = true;
ohrstrom@1504:         String s = newContent.toString();
ohrstrom@1504:         if (!oldContent.equals(s)) {
ohrstrom@1504:             int p = file.getName().lastIndexOf(File.separatorChar);
ohrstrom@1504:             try (Writer writer = file.openWriter()) {
ohrstrom@1504:                 writer.write(s);
ohrstrom@1504:             }
ohrstrom@1504:             stdout.println("Writing "+file.getName().substring(p+1));
ohrstrom@1504:         }
ohrstrom@1504:     }
ohrstrom@1504: 
ohrstrom@1504:     public void flush() throws IOException {
ohrstrom@1504:     }
ohrstrom@1504: }