/*

 * Copyright (c) 2003, 2012, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.management.snmp.jvminstr;

// java imports

//

import com.sun.jmx.mbeanserver.Util;

import java.io.Serializable;

import java.util.Vector;

import java.util.Map;

import java.util.TreeMap;

import java.util.Enumeration;

import java.lang.management.ThreadInfo;

import java.lang.management.ManagementFactory;

// jmx imports

//

import javax.management.MBeanServer;

import javax.management.ObjectName;

import com.sun.jmx.snmp.SnmpCounter;

import com.sun.jmx.snmp.SnmpCounter64;

import com.sun.jmx.snmp.SnmpGauge;

import com.sun.jmx.snmp.SnmpInt;

import com.sun.jmx.snmp.SnmpUnsignedInt;

import com.sun.jmx.snmp.SnmpIpAddress;

import com.sun.jmx.snmp.SnmpTimeticks;

import com.sun.jmx.snmp.SnmpOpaque;

import com.sun.jmx.snmp.SnmpString;

import com.sun.jmx.snmp.SnmpStringFixed;

import com.sun.jmx.snmp.SnmpOid;

import com.sun.jmx.snmp.SnmpNull;

import com.sun.jmx.snmp.SnmpValue;

import com.sun.jmx.snmp.SnmpVarBind;

import com.sun.jmx.snmp.SnmpStatusException;

// jdmk imports

//

import com.sun.jmx.snmp.agent.SnmpIndex;

import com.sun.jmx.snmp.agent.SnmpMib;

import com.sun.jmx.snmp.agent.SnmpMibTable;

import com.sun.jmx.snmp.agent.SnmpMibSubRequest;

import com.sun.jmx.snmp.agent.SnmpStandardObjectServer;

import sun.management.snmp.jvmmib.JvmThreadInstanceEntryMBean;

import sun.management.snmp.jvmmib.JvmThreadInstanceTableMeta;

import sun.management.snmp.util.SnmpTableCache;

import sun.management.snmp.util.SnmpCachedData;

import sun.management.snmp.util.SnmpTableHandler;

import sun.management.snmp.util.MibLogger;

import sun.management.snmp.util.JvmContextFactory;

/**

 * The class is used for implementing the "JvmThreadInstanceTable" group.

 */

public class JvmThreadInstanceTableMetaImpl

    extends JvmThreadInstanceTableMeta {

    static final long serialVersionUID = -8432271929226397492L;

    /**

     * Maximum depth of the stacktrace that might be returned through

     * SNMP.

     *

     * Since we do not export the stack trace through SNMP, we set

     * MAX_STACK_TRACE_DEPTH=0 so that ThreadMXBean.getThreadInfo(long) does

     * not compute the stack trace.

     *

     **/

    public static final int MAX_STACK_TRACE_DEPTH=0;

    /**

     * Translate from a long to a Oid. Arc follow the long big-endian order.

     * @param l The long to make the index from

     * @return The arc array.

     */

    static SnmpOid makeOid(long l) {

        long[] x =  new long [8];

        x[0] = (l >> 56) & 0xFF;

        x[1] =  (l >> 48) & 0x00FF;

        x[2] =  (l >> 40) & 0x0000FF;

        x[3] =  (l >> 32) & 0x000000FF;

        x[4] =  (l >> 24) & 0x00000000FF;

        x[5] =  (l >> 16) & 0x0000000000FF;

        x[6] =  (l >> 8)  & 0x000000000000FF;

        x[7] =  l         & 0x00000000000000FF;

        return new SnmpOid(x);

    }

    /**

     * Translate an Oid to a thread id. Arc follow the long big-endian order.

     * @param oid The oid to make the id from

     * @return The thread id.

     */

    static long makeId(SnmpOid oid) {

        long id = 0;

        long[] arcs = oid.longValue(false);

        id |= arcs[0] << 56;

        id |= arcs[1] << 48;

        id |= arcs[2] << 40;

        id |= arcs[3] << 32;

        id |= arcs[4] << 24;

        id |= arcs[5] << 16;

        id |= arcs[6] << 8;

        id |= arcs[7];

        return id;

    }

    /**

     * A concrete implementation of {@link SnmpTableCache}, for the

     * JvmThreadInstanceTable.

     **/

    private static class JvmThreadInstanceTableCache

        extends SnmpTableCache {

        static final long serialVersionUID = 4947330124563406878L;

        final private JvmThreadInstanceTableMetaImpl meta;

        /**

         * Create a weak cache for the JvmThreadInstanceTable.

         * @param validity validity of the cached data, in ms.

         **/

        JvmThreadInstanceTableCache(JvmThreadInstanceTableMetaImpl meta,

                                   long validity) {

            this.validity = validity;

            this.meta     = meta;

        }

        /**

         * Call <code>getTableDatas(JvmContextFactory.getUserData())</code>.

         **/

        public SnmpTableHandler getTableHandler() {

            final Map<Object, Object> userData = JvmContextFactory.getUserData();

            return getTableDatas(userData);

        }

        /**

         * Return a table handler containing the Thread indexes.

         * Indexes are computed from the ThreadId.

         **/

        protected SnmpCachedData updateCachedDatas(Object userData) {

            // We are getting all the thread ids. WARNING.

            // Some of them will be not valid when accessed for data...

            // See getEntry

            long[] id = JvmThreadingImpl.getThreadMXBean().getAllThreadIds();

            // Time stamp for the cache

            final long time = System.currentTimeMillis();

            SnmpOid indexes[] = new SnmpOid[id.length];

            final TreeMap<SnmpOid, Object> table =

                    new TreeMap<>(SnmpCachedData.oidComparator);

            for(int i = 0; i < id.length; i++) {

                log.debug("", "Making index for thread id [" + id[i] +"]");

                //indexes[i] = makeOid(id[i]);

                SnmpOid oid = makeOid(id[i]);

                table.put(oid, oid);

            }

            return new SnmpCachedData(time, table);

        }

    }

    // The weak cache for this table.

    protected SnmpTableCache cache;

    /**

     * Constructor for the table. Initialize metadata for

     * "JvmThreadInstanceTableMeta".

     * The reference on the MBean server is updated so the entries created

     * through an SNMP SET will be AUTOMATICALLY REGISTERED in Java DMK.

     */

    public JvmThreadInstanceTableMetaImpl(SnmpMib myMib,

                                          SnmpStandardObjectServer objserv) {

        super(myMib, objserv);

        cache = new JvmThreadInstanceTableCache(this,

                            ((JVM_MANAGEMENT_MIB_IMPL)myMib).validity());

        log.debug("JvmThreadInstanceTableMetaImpl", "Create Thread meta");

    }

    // See com.sun.jmx.snmp.agent.SnmpMibTable

    protected SnmpOid getNextOid(Object userData)

        throws SnmpStatusException {

        log.debug("JvmThreadInstanceTableMetaImpl", "getNextOid");

        // null means get the first OID.

        return getNextOid(null,userData);

    }

    // See com.sun.jmx.snmp.agent.SnmpMibTable

    protected SnmpOid getNextOid(SnmpOid oid, Object userData)

        throws SnmpStatusException {

        log.debug("getNextOid", "previous=" + oid);

        // Get the data handler.

        //

        SnmpTableHandler handler = getHandler(userData);

        if (handler == null) {

            // This should never happen.

            // If we get here it's a bug.

            //

            log.debug("getNextOid", "handler is null!");

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        }

        // Get the next oid

        //

        SnmpOid next = oid;

        while(true) {

            next = handler.getNext(next);

            if (next == null) break;

            if (getJvmThreadInstance(userData,next) != null) break;

        }

        log.debug("*** **** **** **** getNextOid", "next=" + next);

        // if next is null: we reached the end of the table.

        //

        if (next == null)

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        return next;

    }

    // See com.sun.jmx.snmp.agent.SnmpMibTable

    protected boolean contains(SnmpOid oid, Object userData) {

        // Get the handler.

        //

        SnmpTableHandler handler = getHandler(userData);

        // handler should never be null.

        //

        if (handler == null)

            return false;

        if(!handler.contains(oid))

            return false;

        JvmThreadInstanceEntryImpl inst = getJvmThreadInstance(userData, oid);

        return (inst != null);

    }

    // See com.sun.jmx.snmp.agent.SnmpMibTable

    public Object getEntry(SnmpOid oid)

        throws SnmpStatusException {

        log.debug("*** **** **** **** getEntry", "oid [" + oid + "]");

        if (oid == null || oid.getLength() != 8) {

            log.debug("getEntry", "Invalid oid [" + oid + "]");

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        }

        // Get the request contextual cache (userData).

        //

        final Map<Object,Object> m = JvmContextFactory.getUserData();

        // Get the handler.

        //

        SnmpTableHandler handler = getHandler(m);

        // handler should never be null.

        //

        if (handler == null || !handler.contains(oid))

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        final JvmThreadInstanceEntryImpl entry = getJvmThreadInstance(m,oid);

        if (entry == null)

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        return entry;

    }

    /**

     * Get the SnmpTableHandler that holds the jvmThreadInstanceTable data.

     * First look it up in the request contextual cache, and if it is

     * not found, obtain it from the weak cache.

     * <br>The request contextual cache will be released at the end of the

     * current requests, and is used only to process this request.

     * <br>The weak cache is shared by all requests, and is only

     * recomputed when it is found to be obsolete.

     * <br>Note that the data put in the request contextual cache is

     *     never considered to be obsolete, in order to preserve data

     *     coherency.

     **/

    protected SnmpTableHandler getHandler(Object userData) {

        final Map<Object, Object> m;

        if (userData instanceof Map) m=Util.cast(userData);

        else m=null;

        // Look in the contextual cache.

        if (m != null) {

            final SnmpTableHandler handler =

                (SnmpTableHandler)m.get("JvmThreadInstanceTable.handler");

            if (handler != null) return handler;

        }

        // No handler in contextual cache, make a new one.

        final SnmpTableHandler handler = cache.getTableHandler();

        if (m != null && handler != null )

            m.put("JvmThreadInstanceTable.handler",handler);

        return handler;

    }

    private ThreadInfo getThreadInfo(long id) {

        return JvmThreadingImpl.getThreadMXBean().

                  getThreadInfo(id,MAX_STACK_TRACE_DEPTH);

    }

    private ThreadInfo getThreadInfo(SnmpOid oid) {

        return getThreadInfo(makeId(oid));

    }

    private JvmThreadInstanceEntryImpl getJvmThreadInstance(Object userData,

                                                            SnmpOid oid) {

        JvmThreadInstanceEntryImpl cached = null;

        String entryTag = null;

        Map<Object, Object> map = null;

        final boolean dbg = log.isDebugOn();

        if (userData instanceof Map) {

            map = Util.cast(userData);

            // We're going to use this name to store/retrieve the entry in

            // the request contextual cache.

            //

            // Revisit: Probably better programming to put all these strings

            //          in some interface.

            //

            entryTag = "JvmThreadInstanceTable.entry." + oid.toString();

            cached = (JvmThreadInstanceEntryImpl) map.get(entryTag);

        }

        // If the entry is in the cache, simply return it.

        //

        if (cached != null) {

            if (dbg) log.debug("*** getJvmThreadInstance",

                               "Entry found in cache: " + entryTag);

            return cached;

        }

        if (dbg) log.debug("*** getJvmThreadInstance", "Entry [" +

                           oid + "] is not in cache");

        // Entry not in cache. We will create one if needed.

        //

        ThreadInfo info = null;

        try {

            info = getThreadInfo(oid);

        } catch (RuntimeException r) {

            log.trace("*** getJvmThreadInstance",

                      "Failed to get thread info for rowOid: " + oid);

            log.debug("*** getJvmThreadInstance",r);

        }

        // No thread by that id => no entry.

        //

        if(info == null) {

            if (dbg) log.debug("*** getJvmThreadInstance",

                               "No entry by that oid [" + oid + "]");

            return null;

        }

        cached = new JvmThreadInstanceEntryImpl(info, oid.toByte());

        if (map != null) map.put(entryTag, cached);

        if (dbg) log.debug("*** getJvmThreadInstance",

                           "Entry created for Thread OID [" + oid + "]");

        return cached;

    }

     static final MibLogger log =

        new MibLogger(JvmThreadInstanceTableMetaImpl.class);

}