/*
 * Copyright 2008 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 sun.tracing;

import java.lang.reflect.Method;
import java.util.logging.Logger;

import com.sun.tracing.ProviderFactory;
import com.sun.tracing.Provider;

/**
 * Factory class to create tracing Providers.
 *
 * This factory will create tracing instances that do nothing.
 * It is used when no tracing is desired, but Provider instances still
 * must be generated so that tracing calls in the application continue to
 * run.
 *
 * @since 1.7
 */
public class NullProviderFactory extends ProviderFactory {

    /**
     * Creates and returns a Null provider.
     *
     * See comments at {@code ProviderSkeleton.createProvider()} for more
     * details.
     *
     * @return a provider whose probe trigger are no-ops.
     */
    public <T extends Provider> T createProvider(Class<T> cls) {
        NullProvider provider = new NullProvider(cls);
        try {
            provider.init();
        } catch (Exception e) {
            // Probably a permission problem (can't get declared members)
            Logger.getAnonymousLogger().warning(
                "Could not initialize tracing provider: " + e.getMessage());
        }
        return provider.newProxyInstance();
    }
}

class NullProvider extends ProviderSkeleton {

    NullProvider(Class<? extends Provider> type) {
        super(type);
    }

    protected ProbeSkeleton createProbe(Method m) {
        return new NullProbe(m.getParameterTypes());
    }
}

class NullProbe extends ProbeSkeleton {

    public NullProbe(Class<?>[] parameters) {
        super(parameters);
    }

    public boolean isEnabled() {
        return false;
    }

    public void uncheckedTrigger(Object[] args) {
    }
}