/*

 * Copyright 2003-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.jmx.remote.util;

import java.io.IOException;

import java.io.ObjectOutputStream;

import java.io.OutputStream;

import java.util.Collection;

import java.util.HashMap;

import java.util.Hashtable;

import java.util.Iterator;

import java.util.Map;

import java.util.SortedMap;

import java.util.SortedSet;

import java.util.StringTokenizer;

import java.util.TreeMap;

import java.util.TreeSet;

import java.security.AccessController;

import javax.management.ObjectName;

import javax.management.MBeanServer;

import javax.management.InstanceNotFoundException;

import javax.management.remote.JMXConnectorFactory;

import javax.management.remote.JMXConnectorServerFactory;

import com.sun.jmx.mbeanserver.GetPropertyAction;

public class EnvHelp {

    /**

     * <p>Name of the attribute that specifies a default class loader

     * object.

     * The value associated with this attribute is a ClassLoader object</p>

     */

    private static final String DEFAULT_CLASS_LOADER =

        JMXConnectorFactory.DEFAULT_CLASS_LOADER;

    /**

     * <p>Name of the attribute that specifies a default class loader

     *    ObjectName.

     * The value associated with this attribute is an ObjectName object</p>

     */

    private static final String DEFAULT_CLASS_LOADER_NAME =

        JMXConnectorServerFactory.DEFAULT_CLASS_LOADER_NAME;

    /**

     * Get the Connector Server default class loader.

     * <p>

     * Returns:

     * <p>

     * <ul>

     * <li>

     *     The ClassLoader object found in <var>env</var> for

     *     <code>jmx.remote.default.class.loader</code>, if any.

     * </li>

     * <li>

     *     The ClassLoader pointed to by the ObjectName found in

     *     <var>env</var> for <code>jmx.remote.default.class.loader.name</code>,

     *     and registered in <var>mbs</var> if any.

     * </li>

     * <li>

     *     The current thread's context classloader otherwise.

     * </li>

     * </ul>

     *

     * @param env Environment attributes.

     * @param mbs The MBeanServer for which the connector server provides

     * remote access.

     *

     * @return the connector server's default class loader.

     *

     * @exception IllegalArgumentException if one of the following is true:

     * <ul>

     * <li>both

     *     <code>jmx.remote.default.class.loader</code> and

     *     <code>jmx.remote.default.class.loader.name</code> are specified,

     * </li>

     * <li>or

     *     <code>jmx.remote.default.class.loader</code> is not

     *     an instance of {@link ClassLoader},

     * </li>

     * <li>or

     *     <code>jmx.remote.default.class.loader.name</code> is not

     *     an instance of {@link ObjectName},

     * </li>

     * <li>or

     *     <code>jmx.remote.default.class.loader.name</code> is specified

     *     but <var>mbs</var> is null.

     * </li>

     * @exception InstanceNotFoundException if

     * <code>jmx.remote.default.class.loader.name</code> is specified

     * and the ClassLoader MBean is not found in <var>mbs</var>.

     */

    public static ClassLoader resolveServerClassLoader(Map env,

                                                       MBeanServer mbs)

        throws InstanceNotFoundException {

        if (env == null)

            return Thread.currentThread().getContextClassLoader();

        Object loader = env.get(DEFAULT_CLASS_LOADER);

        Object name   = env.get(DEFAULT_CLASS_LOADER_NAME);

        if (loader != null && name != null) {

            final String msg = "Only one of " +

                DEFAULT_CLASS_LOADER + " or " +

                DEFAULT_CLASS_LOADER_NAME +

                " should be specified.";

            throw new IllegalArgumentException(msg);

        }

        if (loader == null && name == null)

            return Thread.currentThread().getContextClassLoader();

        if (loader != null) {

            if (loader instanceof ClassLoader) {

                return (ClassLoader) loader;

            } else {

                final String msg =

                    "ClassLoader object is not an instance of " +

                    ClassLoader.class.getName() + " : " +

                    loader.getClass().getName();

                throw new IllegalArgumentException(msg);

            }

        }

        ObjectName on;

        if (name instanceof ObjectName) {

            on = (ObjectName) name;

        } else {

            final String msg =

                "ClassLoader name is not an instance of " +

                ObjectName.class.getName() + " : " +

                name.getClass().getName();

            throw new IllegalArgumentException(msg);

        }

        if (mbs == null)

            throw new IllegalArgumentException("Null MBeanServer object");

        return mbs.getClassLoader(on);

    }

    /**

     * Get the Connector Client default class loader.

     * <p>

     * Returns:

     * <p>

     * <ul>

     * <li>

     *     The ClassLoader object found in <var>env</var> for

     *     <code>jmx.remote.default.class.loader</code>, if any.

     * </li>

     * <li>The <tt>Thread.currentThread().getContextClassLoader()</tt>

     *     otherwise.

     * </li>

     * </ul>

     * <p>

     * Usually a Connector Client will call

     * <pre>

     * ClassLoader dcl = EnvHelp.resolveClientClassLoader(env);

     * </pre>

     * in its <code>connect(Map env)</code> method.

     *

     * @return The connector client default class loader.

     *

     * @exception IllegalArgumentException if

     * <code>jmx.remote.default.class.loader</code> is specified

     * and is not an instance of {@link ClassLoader}.

     */

    public static ClassLoader resolveClientClassLoader(Map env) {

        if (env == null)

            return Thread.currentThread().getContextClassLoader();

        Object loader = env.get(DEFAULT_CLASS_LOADER);

        if (loader == null)

            return Thread.currentThread().getContextClassLoader();

        if (loader instanceof ClassLoader) {

            return (ClassLoader) loader;

        } else {

            final String msg =

                "ClassLoader object is not an instance of " +

                ClassLoader.class.getName() + " : " +

                loader.getClass().getName();

            throw new IllegalArgumentException(msg);

        }

    }

    /**

     * Initialize the cause field of a {@code Throwable} object.

     *

     * @param throwable The {@code Throwable} on which the cause is set.

     * @param cause The cause to set on the supplied {@code Throwable}.

     * @return the {@code Throwable} with the cause field initialized.

     */

    public static <T extends Throwable> T initCause(T throwable,

                                                    Throwable cause) {

        throwable.initCause(cause);

        return throwable;

    }

    /**

     * Returns the cause field of a {@code Throwable} object.

     * The cause field can be got only if <var>t</var> has an

     * {@link Throwable#getCause()} method (JDK Version >= 1.4)

     * @param t {@code Throwable} on which the cause must be set.

     * @return the cause if getCause() succeeded and the got value is not

     * null, otherwise return the <var>t</var>.

     */

    public static Throwable getCause(Throwable t) {

        Throwable ret = t;

        try {

            java.lang.reflect.Method getCause =

                t.getClass().getMethod("getCause", (Class[]) null);

            ret = (Throwable)getCause.invoke(t, (Object[]) null);

        } catch (Exception e) {

            // OK.

            // it must be older than 1.4.

        }

        return (ret != null) ? ret: t;

    }

    /**

     * <p>Name of the attribute that specifies the size of a notification

     * buffer for a connector server. The default value is 1000.

     */

    public static final String BUFFER_SIZE_PROPERTY =

        "jmx.remote.x.notification.buffer.size";

    /**

     * Returns the size of a notification buffer for a connector server.

     * The default value is 1000.

     */

    public static int getNotifBufferSize(Map env) {

        int defaultQueueSize = 1000; // default value

        // keep it for the compability for the fix:

        // 6174229: Environment parameter should be notification.buffer.size

        // instead of buffer.size

        final String oldP = "jmx.remote.x.buffer.size";

        // the default value re-specified in the system

        try {

            GetPropertyAction act = new GetPropertyAction(BUFFER_SIZE_PROPERTY);

            String s = AccessController.doPrivileged(act);

            if (s != null) {

                defaultQueueSize = Integer.parseInt(s);

            } else { // try the old one

                act = new GetPropertyAction(oldP);

                s = AccessController.doPrivileged(act);

                if (s != null) {

                    defaultQueueSize = Integer.parseInt(s);

                }

            }

        } catch (RuntimeException e) {

            logger.warning("getNotifBufferSize",

                           "Can't use System property "+

                           BUFFER_SIZE_PROPERTY+ ": " + e);

              logger.debug("getNotifBufferSize", e);

        }

        int queueSize = defaultQueueSize;

        try {

            if (env.containsKey(BUFFER_SIZE_PROPERTY)) {

                queueSize = (int)EnvHelp.getIntegerAttribute(env,BUFFER_SIZE_PROPERTY,

                                            defaultQueueSize,0,

                                            Integer.MAX_VALUE);

            } else { // try the old one

                queueSize = (int)EnvHelp.getIntegerAttribute(env,oldP,

                                            defaultQueueSize,0,

                                            Integer.MAX_VALUE);

            }

        } catch (RuntimeException e) {

            logger.warning("getNotifBufferSize",

                           "Can't determine queuesize (using default): "+

                           e);

            logger.debug("getNotifBufferSize", e);

        }

        return queueSize;

    }

    /**

     * <p>Name of the attribute that specifies the maximum number of

     * notifications that a client will fetch from its server.. The

     * value associated with this attribute should be an

     * <code>Integer</code> object.  The default value is 1000.</p>

     */

    public static final String MAX_FETCH_NOTIFS =

        "jmx.remote.x.notification.fetch.max";

    /**

     * Returns the maximum notification number which a client will

     * fetch every time.

     */

    public static int getMaxFetchNotifNumber(Map env) {

        return (int) getIntegerAttribute(env, MAX_FETCH_NOTIFS, 1000, 1,

                                         Integer.MAX_VALUE);

    }

    /**

     * <p>Name of the attribute that specifies the timeout for a

     * client to fetch notifications from its server. The value

     * associated with this attribute should be a <code>Long</code>

     * object.  The default value is 60000 milliseconds.</p>

     */

    public static final String FETCH_TIMEOUT =

        "jmx.remote.x.notification.fetch.timeout";

    /**

     * Returns the timeout for a client to fetch notifications.

     */

    public static long getFetchTimeout(Map env) {

        return getIntegerAttribute(env, FETCH_TIMEOUT, 60000L, 0,

    }

    /**

     * Get an integer-valued attribute with name <code>name</code>

     * from <code>env</code>.  If <code>env</code> is null, or does

     * not contain an entry for <code>name</code>, return

     * <code>defaultValue</code>.  The value may be a Number, or it

     * may be a String that is parsable as a long.  It must be at

     * least <code>minValue</code> and at most<code>maxValue</code>.

     *

     * @throws IllegalArgumentException if <code>env</code> contains

     * an entry for <code>name</code> but it does not meet the

     * constraints above.

     */

    public static long getIntegerAttribute(Map env, String name,

                                           long defaultValue, long minValue,

                                           long maxValue) {

        final Object o;

        if (env == null || (o = env.get(name)) == null)

            return defaultValue;

        final long result;

        if (o instanceof Number)

            result = ((Number) o).longValue();

        else if (o instanceof String) {

            result = Long.parseLong((String) o);

            /* May throw a NumberFormatException, which is an

               IllegalArgumentException.  */

        } else {

            final String msg =

                "Attribute " + name + " value must be Integer or String: " + o;

            throw new IllegalArgumentException(msg);

        }

        if (result < minValue) {

            final String msg =

                "Attribute " + name + " value must be at least " + minValue +

                ": " + result;

            throw new IllegalArgumentException(msg);

        }

        if (result > maxValue) {

            final String msg =

                "Attribute " + name + " value must be at most " + maxValue +

                ": " + result;

            throw new IllegalArgumentException(msg);

        }

        return result;

    }

    public static final String DEFAULT_ORB="java.naming.corba.orb";

    /* Check that all attributes have a key that is a String.

       Could make further checks, e.g. appropriate types for attributes.  */

    public static void checkAttributes(Map attributes) {

        for (Iterator it = attributes.keySet().iterator(); it.hasNext(); ) {

            Object key = it.next();

            if (!(key instanceof String)) {

                final String msg =

                    "Attributes contain key that is not a string: " + key;

                throw new IllegalArgumentException(msg);

            }

        }

    }

    /* Return a writable map containing only those attributes that are

       serializable, and that are not hidden by

       jmx.remote.x.hidden.attributes or the default list of hidden

       attributes.  */

    public static <V> Map<String, V> filterAttributes(Map<String, V> attributes) {

        if (logger.traceOn()) {

            logger.trace("filterAttributes", "starts");

        }

        SortedMap<String, V> map = new TreeMap<String, V>(attributes);

        purgeUnserializable(map.values());

        hideAttributes(map);

        return map;

    }

    /**

     * Remove from the given Collection any element that is not a

     * serializable object.

     */

    private static void purgeUnserializable(Collection<?> objects) {

        logger.trace("purgeUnserializable", "starts");

        ObjectOutputStream oos = null;

        int i = 0;

        for (Iterator it = objects.iterator(); it.hasNext(); i++) {

            Object v = it.next();

            if (v == null || v instanceof String) {

                if (logger.traceOn()) {

                    logger.trace("purgeUnserializable",

                                 "Value trivially serializable: " + v);

                }

                continue;

            }

            try {

                if (oos == null)

                    oos = new ObjectOutputStream(new SinkOutputStream());

                oos.writeObject(v);

                if (logger.traceOn()) {

                    logger.trace("purgeUnserializable",

                                 "Value serializable: " + v);

                }

            } catch (IOException e) {

                if (logger.traceOn()) {

                    logger.trace("purgeUnserializable",

                                 "Value not serializable: " + v + ": " +

                                 e);

                }

                it.remove();

                oos = null; // ObjectOutputStream invalid after exception

            }

        }

    }

    /**

     */

    public static final String HIDDEN_ATTRIBUTES =

        "jmx.remote.x.hidden.attributes";

    /**

     */

    /* This list is copied directly from the spec, plus

       java.naming.security.*.  Most of the attributes here would have

       been eliminated from the map anyway because they are typically

       not serializable.  But just in case they are, we list them here

       to conform to the spec.  */

    public static final String DEFAULT_HIDDEN_ATTRIBUTES =

        "java.naming.security.* " +

        "jmx.remote.authenticator " +

        "jmx.remote.context " +

        "jmx.remote.default.class.loader " +

        "jmx.remote.message.connection.server " +

        "jmx.remote.object.wrapping " +

        "jmx.remote.rmi.client.socket.factory " +

        "jmx.remote.rmi.server.socket.factory " +

        "jmx.remote.sasl.callback.handler " +

        "jmx.remote.tls.socket.factory " +

        "jmx.remote.x.access.file " +

        "jmx.remote.x.password.file ";