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 * published by the Free Software Foundation.  Oracle designates this

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 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

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 * 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,

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import java.lang.management.GarbageCollectorMXBean;

import java.lang.management.MemoryUsage;

import javax.management.openmbean.OpenType;

import javax.management.openmbean.SimpleType;

import javax.management.openmbean.CompositeType;

import javax.management.openmbean.OpenDataException;

import com.sun.management.GcInfo;

/**

 * Helper class to build composite data.

 */

public class GcInfoBuilder {

    private final GarbageCollectorMXBean gc;

    private final String[] poolNames;

    private String[] allItemNames;

    // GC-specific composite type:

    // Each GarbageCollectorMXBean may have different GC-specific attributes

    // the CompositeType for the GcInfo could be different.

    private CompositeType gcInfoCompositeType;

    // GC-specific items

    private final int gcExtItemCount;

    private final String[] gcExtItemNames;

    private final String[] gcExtItemDescs;

    private final char[] gcExtItemTypes;

    GcInfoBuilder(GarbageCollectorMXBean gc, String[] poolNames) {

        this.gc = gc;

        this.poolNames = poolNames;

        this.gcExtItemCount = getNumGcExtAttributes(gc);

        this.gcExtItemNames = new String[gcExtItemCount];

        this.gcExtItemDescs = new String[gcExtItemCount];

        this.gcExtItemTypes = new char[gcExtItemCount];

        // Fill the information about extension attributes

        fillGcAttributeInfo(gc, gcExtItemCount, gcExtItemNames,

                            gcExtItemTypes, gcExtItemDescs);

        // lazily build the CompositeType for the GcInfo

        // including the GC-specific extension attributes

        this.gcInfoCompositeType = null;

    }

    GcInfo getLastGcInfo() {

        MemoryUsage[] usageBeforeGC = new MemoryUsage[poolNames.length];

        MemoryUsage[] usageAfterGC = new MemoryUsage[poolNames.length];

        Object[] values = new Object[gcExtItemCount];

        return getLastGcInfo0(gc, gcExtItemCount, values, gcExtItemTypes,

                              usageBeforeGC, usageAfterGC);

    }

    public String[] getPoolNames() {

        return poolNames;

    }

    int getGcExtItemCount() {

        return gcExtItemCount;

    }

    // Returns the CompositeType for the GcInfo including

    // the extension attributes

    synchronized CompositeType getGcInfoCompositeType() {

        if (gcInfoCompositeType != null)

            return gcInfoCompositeType;

        // First, fill with the attributes in the GcInfo

        String[] gcInfoItemNames = GcInfoCompositeData.getBaseGcInfoItemNames();

        OpenType<?>[] gcInfoItemTypes = GcInfoCompositeData.getBaseGcInfoItemTypes();

        int numGcInfoItems = gcInfoItemNames.length;

        int itemCount = numGcInfoItems + gcExtItemCount;

        allItemNames = new String[itemCount];

        String[] allItemDescs = new String[itemCount];

        OpenType<?>[] allItemTypes = new OpenType<?>[itemCount];

        System.arraycopy(gcInfoItemNames, 0, allItemNames, 0, numGcInfoItems);

        System.arraycopy(gcInfoItemNames, 0, allItemDescs, 0, numGcInfoItems);

        System.arraycopy(gcInfoItemTypes, 0, allItemTypes, 0, numGcInfoItems);

        // Then fill with the extension GC-specific attributes, if any.

        if (gcExtItemCount > 0) {

            fillGcAttributeInfo(gc, gcExtItemCount, gcExtItemNames,

                                gcExtItemTypes, gcExtItemDescs);

            System.arraycopy(gcExtItemNames, 0, allItemNames,

                             numGcInfoItems, gcExtItemCount);

            System.arraycopy(gcExtItemDescs, 0, allItemDescs,

                             numGcInfoItems, gcExtItemCount);

            for (int i = numGcInfoItems, j = 0; j < gcExtItemCount; i++, j++) {

                switch (gcExtItemTypes[j]) {

                    case 'Z':

                        allItemTypes[i] = SimpleType.BOOLEAN;

                        break;

                    case 'B':

                        allItemTypes[i] = SimpleType.BYTE;

                        break;

                    case 'C':

                        allItemTypes[i] = SimpleType.CHARACTER;

                        break;

                    case 'S':

                        allItemTypes[i] = SimpleType.SHORT;

                        break;

                    case 'I':

                        allItemTypes[i] = SimpleType.INTEGER;

                        break;

                    case 'J':

                        allItemTypes[i] = SimpleType.LONG;

                        break;

                    case 'F':

                        allItemTypes[i] = SimpleType.FLOAT;

                        break;

                    case 'D':

                        allItemTypes[i] = SimpleType.DOUBLE;

                        break;

                    default:

                        throw new AssertionError(

                            "Unsupported type [" + gcExtItemTypes[i] + "]");

                }

            }

        }

        CompositeType gict = null;

        try {

            final String typeName =

                "sun.management." + gc.getName() + ".GcInfoCompositeType";

            gict = new CompositeType(typeName,

                                     "CompositeType for GC info for " +

                                         gc.getName(),

                                     allItemNames,

                                     allItemDescs,

                                     allItemTypes);

        } catch (OpenDataException e) {

            // shouldn't reach here

        }

        gcInfoCompositeType = gict;

        return gcInfoCompositeType;

    }

    synchronized String[] getItemNames() {

        if (allItemNames == null) {

            // initialize when forming the composite type

            getGcInfoCompositeType();

        }

        return allItemNames;

    }

    // Retrieve information about extension attributes

    private native int getNumGcExtAttributes(GarbageCollectorMXBean gc);

    private native void fillGcAttributeInfo(GarbageCollectorMXBean gc,

                                            int numAttributes,

                                            String[] attributeNames,

                                            char[] types,

                                            String[] descriptions);

    /**

     * Returns the last GcInfo

     *

     * @param gc GarbageCollectorMXBean that the gc info is associated with.

     * @param numExtAtts number of extension attributes

     * @param extAttValues Values of extension attributes to be filled.

     * @param before Memory usage before GC to be filled.

     * @param after Memory usage after GC to be filled.

     */

    private native GcInfo getLastGcInfo0(GarbageCollectorMXBean gc,

                                         int numExtAtts,

                                         Object[] extAttValues,

                                         char[] extAttTypes,

                                         MemoryUsage[] before,

                                         MemoryUsage[] after);

}