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 * Copyright (c) 2004, 2014, 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 sun.jvmstat.perfdata.monitor;

import sun.jvmstat.monitor.*;

import java.util.*;

import java.nio.*;

import java.io.*;

import java.net.*;

import java.util.regex.*;

/**

 * The base classes for the concrete implementations of the HotSpot

 * PerfData instrumentation buffer.

 *

 * @author Brian Doherty

 * @since 1.5

 * @see AbstractPerfDataBuffer

 */

public abstract class PerfDataBufferImpl {

    /**

     * The buffer containing the instrumentation data.

     */

    protected ByteBuffer buffer;

    /**

     * A Map of monitor objects found in the instrumentation buffer.

     */

    protected Map<String, Monitor> monitors;

    /**

     * The Local Java Virtual Machine Identifier for this buffer.

     */

    protected int lvmid;

    /**

     * A Map of monitor object names to aliases as read in from the alias map

     * file.

     */

    protected Map<String, ArrayList<String>> aliasMap;

    /**

     * A cache of resolved monitor aliases.

     */

    protected Map<String, Monitor> aliasCache;

    /**

     * Constructor.

     *

     * @param buffer the ByteBuffer containing the instrumentation data.

     * @param lvmid the Local Java Virtual Machine Identifier for this

     *              instrumentation buffer.

     */

    protected PerfDataBufferImpl(ByteBuffer buffer, int lvmid) {

        this.buffer = buffer;

        this.lvmid = lvmid;

        this.monitors = new TreeMap<>();

        this.aliasMap = new HashMap<>();

        this.aliasCache = new HashMap<>();

    }

    /**

     * Get the Local Java Virtual Machine Identifier, or <em>lvmid</em>

     * for the target JVM associated with this instrumentation buffer.

     *

     * @return int - the lvmid

     */

    public int getLocalVmId() {

        return lvmid;

    }

    /**

     * Get a copy of the raw instrumentation data.

     * This method is used to get a copy of the current bytes in the

     * instrumentation buffer. It is generally used for transporting

     * those bytes over the network.

     *

     * @return byte[] - a copy of the bytes in the instrumentation buffer.

     */

    public byte[] getBytes() {

        ByteBuffer bb = null;

        synchronized (this) {

            /*

             * this operation is potentially time consuming, and the result

             * is unused when the getBytes() interface is used. However, the

             * call is necessary in order to synchronize this monitoring

             * client with the target jvm, which assures that the receiver

             * of the byte[] gets an image that is initialized to a usable

             * state. Otherwise, they might only  get a snapshot of an

             * empty instrumentation buffer immediately after it was created.

             */

            try {

                if (monitors.isEmpty()) {

                    buildMonitorMap(monitors);

                }

            } catch (MonitorException e) {

                /*

                 * just ignore this here and let the receiver of the

                 * byte[] detect and handle the problem.

                 */

            }

            bb = buffer.duplicate();

        }

        bb.rewind();

        byte[] bytes = new byte[bb.limit()];

        bb.get(bytes);

        return bytes;

    }

    /**

     * Get the capacity of the instrumentation buffer.

     *

     * @return int - the capacity, or size, of the instrumentation buffer.

     */

    public int getCapacity() {

        return buffer.capacity();

    }

    /**

     * Get the ByteBuffer containing the instrumentation data.

     *

     * @return ByteBuffer - a ByteBuffer object that refers to the

     *                      instrumentation data.

     */

    ByteBuffer getByteBuffer() {

        // receiver is responsible for assuring that the buffer's state

        // is that of an initialized target.

        return buffer;

    }

    /**

     * Build the alias mapping. Uses the default alias map file unless

     * the sun.jvmstat.perfdata.aliasmap file indicates some other

     * file as the source.

     */

    @SuppressWarnings("deprecation")

    private void buildAliasMap() {

        assert Thread.holdsLock(this);

        URL aliasURL = null;

        String filename = System.getProperty("sun.jvmstat.perfdata.aliasmap");

        if (filename != null) {

            File f = new File(filename);

            try {

                aliasURL = f.toURL();

            } catch (MalformedURLException e) {

                throw new IllegalArgumentException(e);

            }

        } else {

            aliasURL = getClass().getResource(

                "/sun/jvmstat/perfdata/resources/aliasmap");

        }

        assert aliasURL != null;

        AliasFileParser aliasParser = new AliasFileParser(aliasURL);

        try {

            aliasParser.parse(aliasMap);

        } catch (IOException e) {

            System.err.println("Error processing " + filename + ": "

                               + e.getMessage());

        } catch (SyntaxException e) {

            System.err.println("Syntax error parsing " + filename + ": "

                               + e.getMessage());

        }

    }

    /**

     * Find the Monitor object for the named counter by using one of its

     * aliases.

     */

    protected Monitor findByAlias(String name) {

        assert Thread.holdsLock(this);

        Monitor  m = aliasCache.get(name);

        if (m == null) {

            ArrayList<String> al = aliasMap.get(name);

            if (al != null) {

                for (Iterator<String> i = al.iterator(); i.hasNext() && m == null; ) {

                    String alias = i.next();

                    m = monitors.get(alias);

                }

            }

        }

        return m;

    }

    /**

     * Find a named Instrumentation object.

     *

     * This method will look for the named instrumentation object in the

     * instrumentation exported by this Java Virtual Machine. If an

     * instrumentation object with the given name exists, a Monitor interface

     * to that object will be return. Otherwise, the method returns

     * <tt>null</tt>. The method will map requests for instrumention objects

     * using old names to their current names, if applicable.

     *

     *

     *

     * @param name the name of the Instrumentation object to find.

     * @return Monitor - the {@link Monitor} object that can be used to

     *                   <tt>null</tt> if the named object doesn't exist.

     * @throws MonitorException Thrown if an error occurs while communicating

     *                          with the target Java Virtual Machine.

     */

    public Monitor findByName(String name) throws MonitorException {

        Monitor m = null;

        synchronized (this) {

            if (monitors.isEmpty()) {

                buildMonitorMap(monitors);

                buildAliasMap();

            }

            // look for the requested monitor

            m = monitors.get(name);

            if (m == null) {

                // not found - load any new monitors, and try again.

                getNewMonitors(monitors);

                m = monitors.get(name);

            }

            if (m == null) {

                // still not found, look for aliases

                m = findByAlias(name);

            }

        }

        return m;

    }

    /**

     * Find all Instrumentation objects with names matching the given pattern.

     *

     * This method returns a {@link List} of Monitor objects such that

     * the name of each object matches the given pattern.

     *

     * @param patternString a string containing a pattern as described in

     *                      {@link java.util.regex.Pattern}.

     * @return List<Monitor> - a List of {@link Monitor} objects that can be used to

     *                monitor the instrumentation objects whose names match

     *                the given pattern. If no instrumentation objects have`

     *                names matching the given pattern, then an empty List

     *                is returned.

     * @throws MonitorException Thrown if an error occurs while communicating

     *                          with the target Java Virtual Machine.

     * @see java.util.regex.Pattern

     */

    public List<Monitor> findByPattern(String patternString)

                throws MonitorException, PatternSyntaxException {

        synchronized(this) {

            if (monitors.isEmpty()) {

                buildMonitorMap(monitors);

            } else {

                getNewMonitors(monitors);

            }

        }

        Pattern pattern = Pattern.compile(patternString);

        Matcher matcher = pattern.matcher("");

        List<Monitor> matches = new ArrayList<>();

        Set<Map.Entry<String,Monitor>> monitorSet = monitors.entrySet();

        for (Iterator<Map.Entry<String, Monitor>> i = monitorSet.iterator(); i.hasNext(); /* empty */) {

            Map.Entry<String, Monitor> me = i.next();

            String name = me.getKey();

            Monitor m = me.getValue();

            // apply pattern to monitor item name

            matcher.reset(name);

            // if the pattern matches, then add monitor to list

            if (matcher.lookingAt()) {

                 matches.add(me.getValue());

            }

        }

        return matches;

    }

    /**

     * Get a list of the inserted and removed monitors since last called.

     *

     * @return MonitorStatus - the status of available Monitors for the

     *                         target Java Virtual Machine.

     * @throws MonitorException Thrown if communications errors occur

     *                          while communicating with the target.

     */

    public MonitorStatus getMonitorStatus() throws MonitorException {

        synchronized(this) {

            if (monitors.isEmpty()) {

                buildMonitorMap(monitors);

            }

            return getMonitorStatus(monitors);

        }

    }

    // PerfDataBuffer implementation specific classes

    /**

     * get the list of inserted and removed monitors since last called.

     *

     * @param m the map of Monitors.

     * @throws MonitorException Thrown if communications errors occur

     *                          while communicating with the target.

     */

    protected abstract MonitorStatus getMonitorStatus(Map<String, Monitor> m)

                                     throws MonitorException;

    /**

     * build the map of Monitor objects.

     *

     * @param m the map of Monitors.

     * @throws MonitorException Thrown if communications errors occur

     *                          while communicating with the target.

     */

    protected abstract void buildMonitorMap(Map<String, Monitor> m) throws MonitorException;

    /**

     * get the new Monitor objects from the Map of Monitor objects.

     *

     * @param m the map of Monitors.

     * @throws MonitorException Thrown if communications errors occur

     *                          while communicating with the target.

     */

    protected abstract void getNewMonitors(Map<String, Monitor> m) throws MonitorException;

}