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	/*
	* Copyright (c) 2004, 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.jvmstat.perfdata.monitor;

	import sun.misc.Perf;
	import sun.jvmstat.monitor.*;
	import java.util.*;
	import java.io.*;
	import java.lang.reflect.*;
	import java.nio.ByteBuffer;

	/**
	* Abstraction for the HotSpot PerfData instrumentation buffer. This class
	* is responsible for acquiring access to the instrumentation buffer for
	* a target HotSpot Java Virtual Machine and providing method level access
	* to its contents.
	*
	* @author Brian Doherty
	* @since 1.5
	*/
	public abstract class AbstractPerfDataBuffer {

	/**
	* Reference to the concrete instance created by the
	* {@link #createPerfDataBuffer} method.
	*/
	protected PerfDataBufferImpl impl;

	/**
	* Get the Local Java Virtual Machine Identifier, or <em>lvmid</em>
	* for the target JVM associated with this instrumentation buffer.
	*
	* @return int - the lvmid
	*/
	public int getLocalVmId() {
	return impl.getLocalVmId();
	}

	/**
	* Get a copy of the raw instrumentation data.
	* This method is used to get a copy of the current bytes in the
	* instrumentation buffer. It is generally used for transporting
	* those bytes over the network.
	*
	* @return byte[] - a copy of the bytes in the instrumentation buffer.
	*/
	public byte[] getBytes() {
	return impl.getBytes();
	}

	/**
	* Get the capacity of the instrumentation buffer.
	*
	* @return int - the capacity, or size, of the instrumentation buffer.
	*/
	public int getCapacity() {
	return impl.getCapacity();
	}

	/**
	* Find a named Instrumentation object.
	*
	* This method will look for the named instrumentation object in the
	* instrumentation exported by this Java Virtual Machine. If an
	* instrumentation object with the given name exists, a Monitor interface
	* to that object will be return. Otherwise, the method returns
	* <tt>null</tt>.
	*
	* @param name the name of the Instrumentation object to find.
	* @return Monitor - the {@link Monitor} object that can be used to
	* monitor the the named instrumentation object, or
	* <tt>null</tt> if the named object doesn't exist.
	* @throws MonitorException Thrown if an error occurs while communicating
	* with the target Java Virtual Machine.
	*/
	public Monitor findByName(String name) throws MonitorException {
	return impl.findByName(name);
	}

	/**
	* Find all Instrumentation objects with names matching the given pattern.
	*
	* This method returns a {@link List} of Monitor objects such that
	* the name of each object matches the given pattern.
	*
	* @param patternString a string containing a pattern as described in
	* {@link java.util.regex.Pattern}.
	* @return List<Monitor> - a List of {@link Monitor} objects that can be used to
	* monitor the instrumentation objects whose names match
	* the given pattern. If no instrumentation objects have`
	* names matching the given pattern, then an empty List
	* is returned.
	* @throws MonitorException Thrown if an error occurs while communicating
	* with the target Java Virtual Machine.
	* @see java.util.regex.Pattern
	*/
	public List<Monitor> findByPattern(String patternString) throws MonitorException {
	return impl.findByPattern(patternString);
	}

	/**
	* Get a list of the inserted and removed monitors since last called.
	*
	* @return MonitorStatus - the status of available Monitors for the
	* target Java Virtual Machine.
	* @throws MonitorException Thrown if communications errors occur
	* while communicating with the target.
	*/
	public MonitorStatus getMonitorStatus() throws MonitorException {
	return impl.getMonitorStatus();
	}

	/**
	* Get the ByteBuffer containing the instrumentation data.
	*
	* @return ByteBuffer - a ByteBuffer object that refers to the
	* instrumentation data.
	*/
	public ByteBuffer getByteBuffer() {
	return impl.getByteBuffer();
	}

	/**
	* Create the perfdata instrumentation buffer for the given lvmid
	* using the given ByteBuffer object as the source of the instrumentation
	* data. This method parses the instrumentation buffer header to determine
	* key characteristics of the instrumentation buffer and then dynamically
	* loads the appropriate class to handle the particular instrumentation
	* version.
	*
	* @param bb the ByteBuffer that references the instrumentation data.
	* @param lvmid the Local Java Virtual Machine identifier for this
	* instrumentation buffer.
	*
	* @throws MonitorException
	*/
	protected void createPerfDataBuffer(ByteBuffer bb, int lvmid)
	throws MonitorException {
	int majorVersion = AbstractPerfDataBufferPrologue.getMajorVersion(bb);
	int minorVersion = AbstractPerfDataBufferPrologue.getMinorVersion(bb);

	// instantiate the version specific class
	String classname = "sun.jvmstat.perfdata.monitor.v"
	+ majorVersion + "_" + minorVersion
	+ ".PerfDataBuffer";

	try {
	Class<?> implClass = Class.forName(classname);
	Constructor cons = implClass.getConstructor(new Class[] {
	Class.forName("java.nio.ByteBuffer"),
	Integer.TYPE
	});

	impl = (PerfDataBufferImpl)cons.newInstance(new Object[] {
	bb, new Integer(lvmid)
	});

	} catch (ClassNotFoundException e) {
	// from Class.forName();
	throw new IllegalArgumentException(
	"Could not find " + classname + ": " + e.getMessage(), e);

	} catch (NoSuchMethodException e) {
	// from Class.getConstructor();
	throw new IllegalArgumentException(
	"Expected constructor missing in " + classname + ": "
	+ e.getMessage(), e);

	} catch (IllegalAccessException e) {
	// from Constructor.newInstance()
	throw new IllegalArgumentException(
	"Unexpected constructor access in " + classname + ": "
	+ e.getMessage(), e);

	} catch (InstantiationException e) {
	throw new IllegalArgumentException(
	classname + "is abstract: " + e.getMessage(), e);

	} catch (InvocationTargetException e) {
	Throwable cause = e.getCause();
	if (cause instanceof MonitorException) {
	throw (MonitorException)cause;
	}
	throw new RuntimeException("Unexpected exception: "
	+ e.getMessage() , e);
	}
	}
	}

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