FileOutput.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2012 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * GPL Classpath Exception:
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 */

package org.glassfish.admin.amx.util;

import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintStream;

/**
Directs output to a file. Lazy initialization; the file
is not actually opened until output is sent.
 */
public final class FileOutput implements Output
{
    private volatile PrintStream mOut;

    private final File mFile;

    private final boolean mAppend;

    public FileOutput(final File f)
    {
        this(f, false);
    }

    public FileOutput(final File f, boolean append)
    {
        mOut = null;
        mFile = f;
        mAppend = append;
    }

    private void lazyInit()
    {
        if (mOut == null)
        {
            synchronized (this)
            {
                if (mOut == null)
                {
                    try
                    {
                        if ((!mAppend) && mFile.exists())
                        {
                            if (!mFile.delete()) {
                                throw new Exception("cannot delete file: " + mFile);
                            }
                        }

                        mOut = new PrintStream(new FileOutputStream(mFile, mAppend));
                    }
                    catch (Exception e)
                    {
                        // don't use System.out/err; possible infinite recursion
                        throw new RuntimeException("Can't create file: " + mFile +
                                                   ", exception = " + e);
                    }
                }
            }
        }
    }

    public void print(final Object o)
    {
        lazyInit();
        mOut.print(o.toString());
    }

    public void println(Object o)
    {
        lazyInit();
        mOut.println(o.toString());
    }

    public void printError(final Object o)
    {
        lazyInit();
        println("ERROR: " + o);
    }

    public boolean getDebug()
    {
        lazyInit();
        return (false);
    }

    public void printDebug(final Object o)
    {
        lazyInit();
        println("DEBUG: " + o);
    }

    public void close()
    {
        if (mOut != null)
        {
            try
            {
                mOut.close();
            }
            finally
            {
                mOut = null;
            }
        }
    }

};