jdk/src/java.management/share/classes/sun/management/MonitorInfoCompositeData.java

/*
 * Copyright (c) 2005, 2019, 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;

import java.lang.management.MonitorInfo;
import java.util.HashMap;
import java.util.Map;
import javax.management.openmbean.CompositeType;
import javax.management.openmbean.CompositeData;
import javax.management.openmbean.CompositeDataSupport;
import javax.management.openmbean.OpenDataException;
import javax.management.openmbean.OpenType;

/**
 * A CompositeData for MonitorInfo 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 MonitorInfoCompositeData extends LazyCompositeData {
    @SuppressWarnings("serial") // Not statically typed as Serializable
    private final MonitorInfo lock;

    private MonitorInfoCompositeData(MonitorInfo mi) {
        this.lock = mi;
    }

    public MonitorInfo getMonitorInfo() {
        return lock;
    }

    public static CompositeData toCompositeData(MonitorInfo mi) {
        MonitorInfoCompositeData micd = new MonitorInfoCompositeData(mi);
        return micd.getCompositeData();
    }

    protected CompositeData getCompositeData() {
        StackTraceElement ste = lock.getLockedStackFrame();
        CompositeData steCData = ste != null ? StackTraceElementCompositeData.toCompositeData(ste)
                                             : null;
        // values may be null; can't use Map.of
        Map<String,Object> items = new HashMap<>();
        items.put(CLASS_NAME,         lock.getClassName());
        items.put(IDENTITY_HASH_CODE, lock.getIdentityHashCode());
        items.put(LOCKED_STACK_FRAME, steCData);
        items.put(LOCKED_STACK_DEPTH, lock.getLockedStackDepth());

        try {
            return new CompositeDataSupport(MONITOR_INFO_COMPOSITE_TYPE, items);
        } catch (OpenDataException e) {
            // Should never reach here
            throw new AssertionError(e);
        }
    }

    private static final String CLASS_NAME         = "className";
    private static final String IDENTITY_HASH_CODE = "identityHashCode";
    private static final String LOCKED_STACK_FRAME = "lockedStackFrame";
    private static final String LOCKED_STACK_DEPTH = "lockedStackDepth";

    private static final String[] MONITOR_INFO_ATTRIBUTES = {
        CLASS_NAME,
        IDENTITY_HASH_CODE,
        LOCKED_STACK_FRAME,
        LOCKED_STACK_DEPTH
    };

    private static final CompositeType MONITOR_INFO_COMPOSITE_TYPE;
    private static final CompositeType V6_COMPOSITE_TYPE;
    static {
        try {
            MONITOR_INFO_COMPOSITE_TYPE = (CompositeType)
                MappedMXBeanType.toOpenType(MonitorInfo.class);

            OpenType<?>[] types = new OpenType<?>[MONITOR_INFO_ATTRIBUTES.length];
            for (int i = 0; i < MONITOR_INFO_ATTRIBUTES.length; i++) {
                String name = MONITOR_INFO_ATTRIBUTES[i];
                types[i] = name.equals(LOCKED_STACK_FRAME)
                            ? StackTraceElementCompositeData.v5CompositeType()
                            : MONITOR_INFO_COMPOSITE_TYPE.getType(name);
            }
            V6_COMPOSITE_TYPE = new CompositeType("MonitorInfo",
                                                  "JDK 6 MonitorInfo",
                                                  MONITOR_INFO_ATTRIBUTES,
                                                  MONITOR_INFO_ATTRIBUTES,
                                                  types);
        } catch (OpenDataException e) {
            // Should never reach here
            throw new AssertionError(e);
        }
    }

    static CompositeType v6CompositeType() {
        return V6_COMPOSITE_TYPE;
    }

    public static String getClassName(CompositeData cd) {
        return getString(cd, CLASS_NAME);
    }

    public static int getIdentityHashCode(CompositeData cd) {
        return getInt(cd, IDENTITY_HASH_CODE);
    }

    public static StackTraceElement getLockedStackFrame(CompositeData cd) {
        CompositeData ste = (CompositeData) cd.get(LOCKED_STACK_FRAME);
        if (ste != null) {
            return StackTraceElementCompositeData.from(ste);
        } else {
            return null;
        }
    }

    public static int getLockedStackDepth(CompositeData cd) {
        return getInt(cd, LOCKED_STACK_DEPTH);
    }

    /** Validate if the input CompositeData has the expected
     * CompositeType (i.e. contain all attributes with expected
     * names and types).
     */
    public static void validateCompositeData(CompositeData cd) {
        if (cd == null) {
            throw new NullPointerException("Null CompositeData");
        }

        if (!isTypeMatched(MONITOR_INFO_COMPOSITE_TYPE, cd.getCompositeType()) &&
            !isTypeMatched(V6_COMPOSITE_TYPE, cd.getCompositeType())) {
            throw new IllegalArgumentException(
                "Unexpected composite type for MonitorInfo");
        }
    }

    private static final long serialVersionUID = -5825215591822908529L;
}