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 * Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 * 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
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package sun.tracing;

import java.lang.reflect.Method;
import java.lang.reflect.Field;
import com.sun.tracing.Probe;

Provides common code for implementation of Probe classes. 
Since:
1.7/**
 * Provides common code for implementation of {@code Probe} classes.
 *
 * @since 1.7
 */
public abstract class ProbeSkeleton implements Probe {

    protected Class<?>[] parameters;

    protected ProbeSkeleton(Class<?>[] parameters) {
        this.parameters = parameters;
    }

    public abstract boolean isEnabled();  // framework-dependent

    
Triggers the probe with verified arguments.
The caller of this method must have already determined that the
arity and types of the arguments match what the probe was
declared with.
/**
     * Triggers the probe with verified arguments.
     *
     * The caller of this method must have already determined that the
     * arity and types of the arguments match what the probe was
     * declared with.
     */
    public abstract void uncheckedTrigger(Object[] args); // framework-dependent

    private static boolean isAssignable(Object o, Class<?> formal) {
        if (o != null) {
            if ( !formal.isInstance(o) ) {
                if ( formal.isPrimitive() ) { // o might be a boxed primitive
                    try {
                        // Yuck.  There must be a better way of doing this
                        Field f = o.getClass().getField("TYPE");
                        return formal.isAssignableFrom((Class<?>)f.get(null));
                    } catch (Exception e) {
                        /* fall-through. */
                    }
                }
                return false;
            }
        }
        return true;
    }

    
Performs a type-check of the parameters before triggering the probe.
/**
     * Performs a type-check of the parameters before triggering the probe.
     */
    public void trigger(Object ... args) {
        if (args.length != parameters.length) {
            throw new IllegalArgumentException("Wrong number of arguments");
        } else {
            for (int i = 0; i < parameters.length; ++i) {
                if ( !isAssignable(args[i], parameters[i]) ) {
                    throw new IllegalArgumentException(
                            "Wrong type of argument at position " + i);
                }
            }
            uncheckedTrigger(args);
        }
    }
}