/*

 * Copyright (c) 2004, 2006, 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.util.List;

import java.util.Map;

// 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.JvmRTClassPathTableMeta;

import sun.management.snmp.util.SnmpCachedData;

import sun.management.snmp.util.SnmpTableCache;

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 "JvmRTClassPathTable".

  */

public class JvmRTClassPathTableMetaImpl extends JvmRTClassPathTableMeta {

    private SnmpTableCache cache;

     /**

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

     * JvmRTClassPathTable.

     **/

    private static class JvmRTClassPathTableCache extends SnmpTableCache {

        private JvmRTClassPathTableMetaImpl meta;

        JvmRTClassPathTableCache(JvmRTClassPathTableMetaImpl meta,

                                 long validity) {

            this.meta = meta;

            this.validity = validity;

        }

        /**

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

         **/

        public SnmpTableHandler getTableHandler() {

            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 input args

            final String[] path =

                JvmRuntimeImpl.getClassPath(userData);

            // Time stamp for the cache

            final long time = System.currentTimeMillis();

            final int len = path.length;

            SnmpOid indexes[] = new SnmpOid[len];

            for(int i = 0; i < len; i++) {

                indexes[i] = new SnmpOid(i + 1);

            }

            return new SnmpCachedData(time, indexes, path);

        }

    }

    /**

     * Constructor for the table. Initialize metadata for

     * "JvmRTClassPathTableMeta".

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

     * created through an SNMP SET will be AUTOMATICALLY REGISTERED

     * in Java DMK.

     */

    public JvmRTClassPathTableMetaImpl(SnmpMib myMib,

                                       SnmpStandardObjectServer objserv) {

        super(myMib, objserv);

        cache = new JvmRTClassPathTableCache(this, -1);

    }

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

    protected SnmpOid getNextOid(Object userData)

        throws SnmpStatusException {

        // 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 {

        final boolean dbg = log.isDebugOn();

        if (dbg) 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.

            //

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

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        }

        // Get the next oid

        //

        final SnmpOid next = handler.getNext(oid);

        if (dbg) 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;

        return handler.contains(oid);

    }

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

    public Object getEntry(SnmpOid oid)

        throws SnmpStatusException {

        final boolean dbg = log.isDebugOn();

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

        if (oid == null || oid.getLength() != 1) {

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

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        }

        // Get the request contextual cache (userData).

        //

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

        // 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.

        //

        final String entryTag = ((m==null)?null:

                                 ("JvmRTClassPathTable.entry." +

                                  oid.toString()));

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

        //

        if (m != null) {

            final Object entry = m.get(entryTag);

            if (entry != null) {

                if (dbg)

                    log.debug("getEntry", "Entry is already in the cache");

                return entry;

            } else

                if (dbg) log.debug("getEntry", "Entry is not in the cache");

        }

        // The entry was not in the cache, make a new one.

        //

        // Get the data hanler.

        //

        SnmpTableHandler handler = getHandler(m);

        // handler should never be null.

        //

        if (handler == null)

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        // Get the data associated with our entry.

        //

        final Object data = handler.getData(oid);

        // data may be null if the OID we were given is not valid.

        //

        if (data == null)

            throw new SnmpStatusException(SnmpStatusException.noSuchInstance);

        // make the new entry (transient object that will be kept only

        // for the duration of the request.

        //

        if (dbg)

            log.debug("getEntry","data is a: " + data.getClass().getName());

        final Object entry =

            new JvmRTClassPathEntryImpl((String) data, (int) oid.getOidArc(0));

        // Put the entry in the cache in case we need it later while processing

        // the request.

        //

        if (m != null && entry != null) {

            m.put(entryTag,entry);

        }

        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("JvmRTClassPathTable.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("JvmRTClassPathTable.handler",handler);

        return handler;

    }

    static final MibLogger log =

        new MibLogger(JvmRTClassPathTableMetaImpl.class);

}