/*
 * Copyright (c) 2015, 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.
 *
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;

/**
 * This is a base class for any tests which are intended to test -XX:Print*
 * options by parsing GC log output. It encapsulates reading GC's log
 * output from the log file and provides that output to the tests.
 *
 * NOTE: It assumes that the log filename is determined from the test's class
 * name by removing leading 'Test' and adding '.txt' suffix. For instance,
 * the test class TestWhatever corresponds to the log filename Whatever.txt.
 *
 */
public abstract class AbstractPrintGCTest {

    private final String logFileName;

    /**
     * Constructs a test object. Binds the test's name with the GC's log 
     * filename.
     */
    public AbstractPrintGCTest() {
        String className = getClass().getName();
        if (!className.startsWith("Test")) {
            throw new IllegalStateException(
                "The test's class name shall starts with 'Test'");
        }
        logFileName = getClass().getName().substring("Test".length()) 
            + ".txt";
    }

    /**
     * Retrieves content of GC's log file.
     */
    public final String getContent() {
        try {
            return new String(Files.readAllBytes(Paths.get(logFileName)),
                Charset.defaultCharset());
        } catch (IOException e) {
            throw new RuntimeException(
                "Failed to retrieve content from the log file: "
                    + logFileName, e);
        }
    }

    /**
     * The test code goes here.
     */
    public abstract void runTest();
}