/*
 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.tools.sjavac.comp;

import com.sun.tools.sjavac.Log;

import java.io.*;
import javax.tools.JavaFileObject;

The SmartWriter will cache the written data and when the writer is closed,
then it will compare the cached data with the old_content string.
If different, then it will write all the new content to the file.
If not, the file is not touched.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 * The SmartWriter will cache the written data and when the writer is closed,
 * then it will compare the cached data with the old_content string.
 * If different, then it will write all the new content to the file.
 * If not, the file is not touched.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class SmartWriter extends Writer {

    String name;
    JavaFileObject file;
    String oldContent;
    StringWriter newContent = new StringWriter();
    boolean closed;

    public SmartWriter(JavaFileObject f, String s, String n) {
        name = n;
        file = f;
        oldContent = s;
        newContent = new StringWriter();
        closed = false;
    }

    public void write(char[] chars, int i, int i1) {
        newContent.write(chars, i, i1);
    }

    public void close() throws IOException {
        if (closed) return;
        closed = true;
        String s = newContent.toString();
        if (!oldContent.equals(s)) {
            int p = file.getName().lastIndexOf(File.separatorChar);
            try (Writer writer = file.openWriter()) {
                writer.write(s);
            }
            Log.debug("Writing " + file.getName().substring(p + 1));
        }
    }

    public void flush() throws IOException {
    }
}