JDK14/Java14源码在线阅读
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* 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
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package jdk.jfr.internal;
import java.io.IOException;
import java.util.List;
import jdk.internal.HotSpotIntrinsicCandidate;
import jdk.jfr.Event;
/**
* Interface against the JVM.
*
*/
public final class JVM {
private static final JVM jvm = new JVM();
// JVM signals file changes by doing Object#notifu on this object
static final Object FILE_DELTA_CHANGE = new Object();
static final long RESERVED_CLASS_ID_LIMIT = 400;
private volatile boolean nativeOK;
private static native void registerNatives();
static {
registerNatives();
for (LogTag tag : LogTag.values()) {
subscribeLogLevel(tag, tag.id);
}
Options.ensureInitialized();
}
/**
* Get the one and only JVM.
*
* @return the JVM
*/
public static JVM getJVM() {
return jvm;
}
private JVM() {
}
/**
* Marks current chunk as final
* <p>
* This allows streaming clients to read the chunk header and
* close the stream when no more data will be written into
* the current repository.
*/
public native void markChunkFinal();
/**
* Begin recording events
*
* Requires that JFR has been started with {@link #createNativeJFR()}
*/
public native void beginRecording();
/**
* Return true if the JVM is recording
*/
public native boolean isRecording();
/**
* End recording events, which includes flushing data in thread buffers
*
* Requires that JFR has been started with {@link #createNativeJFR()}
*
*/
public native void endRecording();
/**
* Return ticks
*
* @return the time, in ticks
*
*/
@HotSpotIntrinsicCandidate
public static native long counterTime();
/**
* Emits native periodic event.
*
* @param eventTypeId type id
*
* @param timestamp commit time for event
* @param when when it is being done {@link Periodic.When}
*
* @return true if the event was committed
*/
public native boolean emitEvent(long eventTypeId, long timestamp, long when);
/**
* Return a list of all classes deriving from {@link jdk.internal.event.Event}
*
* @return list of event classes.
*/
public native List<Class<? extends jdk.internal.event.Event>> getAllEventClasses();
/**
* Return a count of the number of unloaded classes deriving from {@link Event}
*
* @return number of unloaded event classes.
*/
public native long getUnloadedEventClassCount();
/**
* Return a unique identifier for a class. The class is marked as being
* "in use" in JFR.
*
* @param clazz clazz
*
* @return a unique class identifier
*/
@HotSpotIntrinsicCandidate
public static native long getClassId(Class<?> clazz);
// temporary workaround until we solve intrinsics supporting epoch shift tagging
public static native long getClassIdNonIntrinsic(Class<?> clazz);
/**
* Return process identifier.
*
* @return process identifier
*/
public native String getPid();
/**
* Return unique identifier for stack trace.
*
* Requires that JFR has been started with {@link #createNativeJFR()}
*
* @param skipCount number of frames to skip
* @return a unique stack trace identifier
*/
public native long getStackTraceId(int skipCount);
/**
* Return identifier for thread
*
* @param t thread
* @return a unique thread identifier
*/
public native long getThreadId(Thread t);
/**
* Frequency, ticks per second
*
* @return frequency
*/
public native long getTicksFrequency();
/**
* Write message to log. Should swallow null or empty message, and be able
* to handle any Java character and not crash with very large message
*
* @param tagSetId the tagset id
* @param level on level
* @param message log message
*
*/
public static native void log(int tagSetId, int level, String message);
/**
* Subscribe to LogLevel updates for LogTag
*
* @param lt the log tag to subscribe
* @param tagSetId the tagset id
*/
public static native void subscribeLogLevel(LogTag lt, int tagSetId);
/**
* Call to invoke event tagging and retransformation of the passed classes
*
* @param classes
*
* @throws IllegalStateException if wrong JVMTI phase.
*/
public native synchronized void retransformClasses(Class<?>[] classes);
/**
* Enable event
*
* @param eventTypeId event type id
*
* @param enabled enable event
*/
public native void setEnabled(long eventTypeId, boolean enabled);
/**
* Interval at which the JVM should notify on {@link #FILE_DELTA_CHANGE}
*
* @param delta number of bytes, reset after file rotation
*/
public native void setFileNotification(long delta);
/**
* Set the number of global buffers to use
*
* @param count
*
* @throws IllegalArgumentException if count is not within a valid range
* @throws IllegalStateException if value can't be changed
*/
public native void setGlobalBufferCount(long count) throws IllegalArgumentException, IllegalStateException;
/**
* Set size of a global buffer
*
* @param size
*
* @throws IllegalArgumentException if buffer size is not within a valid
* range
*/
public native void setGlobalBufferSize(long size) throws IllegalArgumentException;
/**
* Set overall memory size
*
* @param size
*
* @throws IllegalArgumentException if memory size is not within a valid
* range
*/
public native void setMemorySize(long size) throws IllegalArgumentException;
/**
/**
* Set interval for method samples, in milliseconds.
*
* Setting interval to 0 turns off the method sampler.
*
* @param intervalMillis the sampling interval
*/
public native void setMethodSamplingInterval(long type, long intervalMillis);
/**
* Sets the file where data should be written.
*
* Requires that JFR has been started with {@link #createNativeJFR()}
*
* <pre>
* Recording Previous Current Action
* ==============================================
* true null null Ignore, keep recording in-memory
* true null file1 Start disk recording
* true file null Copy out metadata to disk and continue in-memory recording
* true file1 file2 Copy out metadata and start with new File (file2)
* false * null Ignore, but start recording to memory with {@link #beginRecording()}
* false * file Ignore, but start recording to disk with {@link #beginRecording()}
*
* </pre>
*
* recording can be set to true/false with {@link #beginRecording()}
* {@link #endRecording()}
*
* @param file the file where data should be written, or null if it should
* not be copied out (in memory).
* @throws IOException
*/
public native void setOutput(String file);
/**
* Controls if a class deriving from jdk.jfr.Event should
* always be instrumented on class load.
*
* @param force, true to force initialization, false otherwise
*/
public native void setForceInstrumentation(boolean force);
/**
* Turn on/off thread sampling.
*
* @param sampleThreads true if threads should be sampled, false otherwise.
*
* @throws IllegalStateException if state can't be changed.
*/
public native void setSampleThreads(boolean sampleThreads) throws IllegalStateException;
/**
* Turn on/off compressed integers.
*
* @param compressed true if compressed integers should be used, false
* otherwise.
*
* @throws IllegalStateException if state can't be changed.
*/
public native void setCompressedIntegers(boolean compressed) throws IllegalStateException;
/**
* Set stack depth.
*
* @param depth
*
* @throws IllegalArgumentException if not within a valid range
* @throws IllegalStateException if depth can't be changed
*/
public native void setStackDepth(int depth) throws IllegalArgumentException, IllegalStateException;
/**
* Turn on stack trace for an event
*
* @param eventTypeId the event id
*
* @param enabled if stack traces should be enabled
*/
public native void setStackTraceEnabled(long eventTypeId, boolean enabled);
/**
* Set thread buffer size.
*
* @param size
*
* @throws IllegalArgumentException if size is not within a valid range
* @throws IllegalStateException if size can't be changed
*/
public native void setThreadBufferSize(long size) throws IllegalArgumentException, IllegalStateException;
/**
* Set threshold for event,
*
* Long.MAXIMUM_VALUE = no limit
*
* @param eventTypeId the id of the event type
* @param ticks threshold in ticks,
* @return true, if it could be set
*/
public native boolean setThreshold(long eventTypeId, long ticks);
/**
* Store the metadata descriptor that is to be written at the end of a
* chunk, data should be written after GMT offset and size of metadata event
* should be adjusted
*
* Requires that JFR has been started with {@link #createNativeJFR()}
*
* @param bytes binary representation of metadata descriptor
*
* @param binary representation of descriptor
*/
public native void storeMetadataDescriptor(byte[] bytes);
/**
* If the JVM supports JVM TI and retransformation has not been disabled this
* method will return true. This flag can not change during the lifetime of
* the JVM.
*
* @return if transform is allowed
*/
public native boolean getAllowedToDoEventRetransforms();
/**
* Set up native resources, data structures, threads etc. for JFR
*
* @param simulateFailure simulate a initialization failure and rollback in
* native, used for testing purposes
*
* @throws IllegalStateException if native part of JFR could not be created.
*
*/
private native boolean createJFR(boolean simulateFailure) throws IllegalStateException;
/**
* Destroys native part of JFR. If already destroy, call is ignored.
*
* Requires that JFR has been started with {@link #createNativeJFR()}
*
* @return if an instance was actually destroyed.
*
*/
private native boolean destroyJFR();
public boolean createFailedNativeJFR() throws IllegalStateException {
return createJFR(true);
}
public void createNativeJFR() {
nativeOK = createJFR(false);
}
public boolean destroyNativeJFR() {
boolean result = destroyJFR();
nativeOK = !result;
return result;
}
public boolean hasNativeJFR() {
return nativeOK;
}
/**
* Cheap test to check if JFR functionality is available.
*
* @return
*/
public native boolean isAvailable();
/**
* To convert ticks to wall clock time.
*/
public native double getTimeConversionFactor();
/**
* Return a unique identifier for a class. Compared to {@link #getClassId()}
* , this method does not tag the class as being "in-use".
*
* @param clazz class
*
* @return a unique class identifier
*/
public native long getTypeId(Class<?> clazz);
/**
* Fast path fetching the EventWriter using VM intrinsics
*
* @return thread local EventWriter
*/
@HotSpotIntrinsicCandidate
public static native Object getEventWriter();
/**
* Create a new EventWriter
*
* @return thread local EventWriter
*/
public static native EventWriter newEventWriter();
/**
* Flushes the EventWriter for this thread.
*/
public static native boolean flush(EventWriter writer, int uncommittedSize, int requestedSize);
/**
* Flushes all thread buffers to disk and the constant pool data needed to read
* them.
* <p>
* When the method returns, the chunk header should be updated with valid
* pointers to the metadata event, last check point event, correct file size and
* the generation id.
*
*/
public native void flush();
/**
* Sets the location of the disk repository, to be used at an emergency
* dump.
*
* @param dirText
*/
public native void setRepositoryLocation(String dirText);
/**
* Access to VM termination support.
*
*@param errorMsg descriptive message to be include in VM termination sequence
*/
public native void abort(String errorMsg);
/**
* Adds a string to the string constant pool.
*
* If the same string is added twice, two entries will be created.
*
* @param id identifier associated with the string, not negative
*
* @param s string constant to be added, not null
*
* @return the current epoch of this insertion attempt
*/
public static native boolean addStringConstant(boolean epoch, long id, String s);
/**
* Gets the address of the jboolean epoch.
*
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