/*

 * 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.

 */

import java.lang.management.MemoryUsage;

import java.lang.reflect.Method;

import java.lang.reflect.Field;

import java.util.Map;

import java.io.InvalidObjectException;

import javax.management.openmbean.CompositeType;

import javax.management.openmbean.CompositeData;

import javax.management.openmbean.CompositeDataSupport;

import javax.management.openmbean.TabularData;

import javax.management.openmbean.SimpleType;

import javax.management.openmbean.OpenType;

import javax.management.openmbean.OpenDataException;

import com.sun.management.GcInfo;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * A CompositeData for GcInfo for the local management support.

 * This class avoids the performance penalty paid to the

 * construction of a CompositeData use in the local case.

 */

public class GcInfoCompositeData extends LazyCompositeData {

    private final GcInfo info;

    private final GcInfoBuilder builder;

    private final Object[] gcExtItemValues;

    public GcInfoCompositeData(GcInfo info,

                        GcInfoBuilder builder,

                        Object[] gcExtItemValues) {

        this.info = info;

        this.builder = builder;

        this.gcExtItemValues = gcExtItemValues;

    }

    public GcInfo getGcInfo() {

        return info;

    }

    public static CompositeData toCompositeData(final GcInfo info) {

        final GcInfoBuilder builder = AccessController.doPrivileged (new PrivilegedAction<GcInfoBuilder>() {

                        public GcInfoBuilder run() {

                            try {

                                Class<?> cl = Class.forName("com.sun.management.GcInfo");

                                Field f = cl.getDeclaredField("builder");

                                f.setAccessible(true);

                                return (GcInfoBuilder)f.get(info);

                            } catch(ClassNotFoundException | NoSuchFieldException | IllegalAccessException e) {

                                return null;

                            }

                        }

                    });

        final Object[] extAttr = AccessController.doPrivileged (new PrivilegedAction<Object[]>() {

                        public Object[] run() {

                            try {

                                Class<?> cl = Class.forName("com.sun.management.GcInfo");

                                Field f = cl.getDeclaredField("extAttributes");

                                f.setAccessible(true);

                                return (Object[])f.get(info);

                            } catch(ClassNotFoundException | NoSuchFieldException | IllegalAccessException e) {

                                return null;

                            }

                        }

                    });

        GcInfoCompositeData gcicd =

            new GcInfoCompositeData(info,builder,extAttr);

        return gcicd.getCompositeData();

    }

    protected CompositeData getCompositeData() {

        // CONTENTS OF THIS ARRAY MUST BE SYNCHRONIZED WITH

        // baseGcInfoItemNames!

        final Object[] baseGcInfoItemValues;

        try {

            baseGcInfoItemValues = new Object[] {

                info.getId(),

                info.getStartTime(),

                info.getEndTime(),

                info.getDuration(),

                memoryUsageMapType.toOpenTypeData(info.getMemoryUsageBeforeGc()),

                memoryUsageMapType.toOpenTypeData(info.getMemoryUsageAfterGc()),

            };

        } catch (OpenDataException e) {

            // Should never reach here

            throw new AssertionError(e);

        }

        // Get the item values for the extension attributes

        final int gcExtItemCount = builder.getGcExtItemCount();

        if (gcExtItemCount == 0 &&

            gcExtItemValues != null && gcExtItemValues.length != 0) {

            throw new AssertionError("Unexpected Gc Extension Item Values");

        }

        if (gcExtItemCount > 0 && (gcExtItemValues == null ||

             gcExtItemCount != gcExtItemValues.length)) {

            throw new AssertionError("Unmatched Gc Extension Item Values");

        }

        Object[] values = new Object[baseGcInfoItemValues.length +

                                     gcExtItemCount];

        System.arraycopy(baseGcInfoItemValues, 0, values, 0,

                         baseGcInfoItemValues.length);

        if (gcExtItemCount > 0) {

            System.arraycopy(gcExtItemValues, 0, values,

                             baseGcInfoItemValues.length, gcExtItemCount);

        }

        try {

            return new CompositeDataSupport(builder.getGcInfoCompositeType(),

                                            builder.getItemNames(),

                                            values);

        } catch (OpenDataException e) {

            // Should never reach here

            throw new AssertionError(e);

        }

    }

    private static final String ID                     = "id";

    private static final String START_TIME             = "startTime";

    private static final String END_TIME               = "endTime";

    private static final String DURATION               = "duration";

    private static final String MEMORY_USAGE_BEFORE_GC = "memoryUsageBeforeGc";

    private static final String MEMORY_USAGE_AFTER_GC  = "memoryUsageAfterGc";

    private static final String[] baseGcInfoItemNames = {

        ID,

        START_TIME,

        END_TIME,

        DURATION,

        MEMORY_USAGE_BEFORE_GC,

        MEMORY_USAGE_AFTER_GC,

    };

    private static MappedMXBeanType memoryUsageMapType;

    static {

        try {

            Method m = GcInfo.class.getMethod("getMemoryUsageBeforeGc");

            memoryUsageMapType =

                MappedMXBeanType.getMappedType(m.getGenericReturnType());

        } catch (NoSuchMethodException | OpenDataException e) {

            // Should never reach here

            throw new AssertionError(e);

        }

    }

    static String[] getBaseGcInfoItemNames() {

        return baseGcInfoItemNames;

    }

    private static OpenType<?>[] baseGcInfoItemTypes = null;

    static synchronized OpenType<?>[] getBaseGcInfoItemTypes() {

        if (baseGcInfoItemTypes == null) {

            OpenType<?> memoryUsageOpenType = memoryUsageMapType.getOpenType();

            baseGcInfoItemTypes = new OpenType<?>[] {

                SimpleType.LONG,

                SimpleType.LONG,

                SimpleType.LONG,

                SimpleType.LONG,

                memoryUsageOpenType,

                memoryUsageOpenType,

            };

        }

        return baseGcInfoItemTypes;

    }

    public static long getId(CompositeData cd) {

        return getLong(cd, ID);

    }

    public static long getStartTime(CompositeData cd) {

        return getLong(cd, START_TIME);

    }

    public static long getEndTime(CompositeData cd) {

        return getLong(cd, END_TIME);

    }

    public static Map<String, MemoryUsage>

            getMemoryUsageBeforeGc(CompositeData cd) {

        try {

            TabularData td = (TabularData) cd.get(MEMORY_USAGE_BEFORE_GC);

            return cast(memoryUsageMapType.toJavaTypeData(td));

        } catch (InvalidObjectException | OpenDataException e) {

            // Should never reach here

            throw new AssertionError(e);

        }

    }

    @SuppressWarnings("unchecked")

    public static Map<String, MemoryUsage> cast(Object x) {

        return (Map<String, MemoryUsage>) x;

    }

    public static Map<String, MemoryUsage>

            getMemoryUsageAfterGc(CompositeData cd) {

        try {

            TabularData td = (TabularData) cd.get(MEMORY_USAGE_AFTER_GC);

            //return (Map<String,MemoryUsage>)

            return cast(memoryUsageMapType.toJavaTypeData(td));

        } catch (InvalidObjectException | OpenDataException e) {

            // Should never reach here

            throw new AssertionError(e);

        }

    }

    /**

     * Returns true if the input CompositeData has the expected

     * CompositeType (i.e. contain all attributes with expected

     * names and types).  Otherwise, return false.

     */

    public static void validateCompositeData(CompositeData cd) {

        if (cd == null) {

            throw new NullPointerException("Null CompositeData");

        }

        if (!isTypeMatched(getBaseGcInfoCompositeType(),

                           cd.getCompositeType())) {

           throw new IllegalArgumentException(

                "Unexpected composite type for GcInfo");

        }

    }

    // This is only used for validation.

    private static CompositeType baseGcInfoCompositeType = null;

    static synchronized CompositeType getBaseGcInfoCompositeType() {

        if (baseGcInfoCompositeType == null) {

            try {

                baseGcInfoCompositeType =

                    new CompositeType("sun.management.BaseGcInfoCompositeType",

                                      "CompositeType for Base GcInfo",

                                      getBaseGcInfoItemNames(),

                                      getBaseGcInfoItemNames(),

                                      getBaseGcInfoItemTypes());

            } catch (OpenDataException e) {

                // shouldn't reach here

            }

        }

        return baseGcInfoCompositeType;

    }

    private static final long serialVersionUID = -5716428894085882742L;

}