LockInfoCompositeData.java

/*
 * Copyright (c) 2012, 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.LockInfo;
import javax.management.openmbean.CompositeType;
import javax.management.openmbean.CompositeData;
import javax.management.openmbean.CompositeDataSupport;
import javax.management.openmbean.OpenDataException;

/**
 * A CompositeData for LockInfo 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 LockInfoCompositeData extends LazyCompositeData {
    private final LockInfo lock;

    private LockInfoCompositeData(LockInfo li) {
        this.lock = li;
    }

    public LockInfo getLockInfo() {
        return lock;
    }

    public static CompositeData toCompositeData(LockInfo li) {
        if (li == null) {
            return null;
        }

        LockInfoCompositeData licd = new LockInfoCompositeData(li);
        return licd.getCompositeData();
    }

    protected CompositeData getCompositeData() {
        // CONTENTS OF THIS ARRAY MUST BE SYNCHRONIZED WITH
        // lockInfoItemNames!
        final Object[] lockInfoItemValues = {
            new String(lock.getClassName()),
            lock.getIdentityHashCode(),
        };

        try {
            return new CompositeDataSupport(lockInfoCompositeType,
                                            lockInfoItemNames,
                                            lockInfoItemValues);
        } catch (OpenDataException e) {
            // Should never reach here
            throw Util.newException(e);
        }
    }

    private static final CompositeType lockInfoCompositeType;
    static {
        try {
            lockInfoCompositeType = (CompositeType)
                MappedMXBeanType.toOpenType(LockInfo.class);
        } catch (OpenDataException e) {
            // Should never reach here
            throw Util.newException(e);
        }
    }

    static CompositeType getLockInfoCompositeType() {
        return lockInfoCompositeType;
    }

    private static final String CLASS_NAME         = "className";
    private static final String IDENTITY_HASH_CODE = "identityHashCode";
    private static final String[] lockInfoItemNames = {
        CLASS_NAME,
        IDENTITY_HASH_CODE,
    };

    /*
     * Returns a LockInfo object mapped from the given CompositeData.
     */
    public static LockInfo toLockInfo(CompositeData cd) {
        if (cd == null) {
            throw new NullPointerException("Null CompositeData");
        }

        if (!isTypeMatched(lockInfoCompositeType, cd.getCompositeType())) {
            throw new IllegalArgumentException(
                "Unexpected composite type for LockInfo");
        }

        String className = getString(cd, CLASS_NAME);
        int identityHashCode = getInt(cd, IDENTITY_HASH_CODE);
        return new LockInfo(className, identityHashCode);
    }

    private static final long serialVersionUID = -6374759159749014052L;
}