aoqi@0: /*
aoqi@0:  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: package com.sun.tools.sjavac.comp;
aoqi@0: 
aoqi@0: import java.io.*;
aoqi@0: import javax.tools.JavaFileObject;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * The SmartWriter will cache the written data and when the writer is closed,
aoqi@0:  * then it will compare the cached data with the old_content string.
aoqi@0:  * If different, then it will write all the new content to the file.
aoqi@0:  * If not, the file is not touched.
aoqi@0:  *
aoqi@0:  *  <p><b>This is NOT part of any supported API.
aoqi@0:  * If you write code that depends on this, you do so at your own
aoqi@0:  * risk.  This code and its internal interfaces are subject to change
aoqi@0:  * or deletion without notice.</b></p>
aoqi@0:  */
aoqi@0: public class SmartWriter extends Writer {
aoqi@0: 
aoqi@0:     String name;
aoqi@0:     JavaFileObject file;
aoqi@0:     String oldContent;
aoqi@0:     StringWriter newContent = new StringWriter();
aoqi@0:     PrintWriter stdout;
aoqi@0:     boolean closed;
aoqi@0:     public SmartWriter(JavaFileObject f, String s, String n, PrintWriter pw) {
aoqi@0:         name = n;
aoqi@0:         file = f;
aoqi@0:         oldContent = s;
aoqi@0:         newContent = new StringWriter();
aoqi@0:         stdout = pw;
aoqi@0:         closed = false;
aoqi@0:     }
aoqi@0: 
aoqi@0:     public void write(char[] chars, int i, int i1)
aoqi@0:     {
aoqi@0:         newContent.write(chars, i, i1);
aoqi@0:     }
aoqi@0: 
aoqi@0:     public void close() throws IOException {
aoqi@0:         if (closed) return;
aoqi@0:         closed = true;
aoqi@0:         String s = newContent.toString();
aoqi@0:         if (!oldContent.equals(s)) {
aoqi@0:             int p = file.getName().lastIndexOf(File.separatorChar);
aoqi@0:             try (Writer writer = file.openWriter()) {
aoqi@0:                 writer.write(s);
aoqi@0:             }
aoqi@0:             stdout.println("Writing "+file.getName().substring(p+1));
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     public void flush() throws IOException {
aoqi@0:     }
aoqi@0: }