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package com.sun.tools.attach.spi;
import java.io.IOException;
import java.util.Collections;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.List;
import com.sun.tools.attach.VirtualMachine;
import com.sun.tools.attach.VirtualMachineDescriptor;
import com.sun.tools.attach.AttachPermission;
import com.sun.tools.attach.AttachNotSupportedException;
import java.util.ServiceLoader;
Attach provider class for attaching to a Java virtual machine.
An attach provider is a concrete subclass of this class that has a
zero-argument constructor and implements the abstract methods specified
below.
An attach provider implementation is typically tied to a Java virtual
machine implementation, version, or even mode of operation. That is, a specific
provider implementation will typically only be capable of attaching to
a specific Java virtual machine implementation or version. For example, Oracle's
JDK implementation ships with provider implementations that can only attach to
Oracle's HotSpot virtual machine. In general, if an environment
consists of Java virtual machines of different versions and from different
vendors then there will be an attach provider implementation for each
family of implementations or versions.
An attach provider is identified by its name and type. The name is typically, but not required to
be, a name that corresponds to the VM vendor. The Oracle JDK implementation,
for example, ships with attach providers that use the package name "sun"
(for historical reasons). The
type typically corresponds to the attach mechanism. For example, an
implementation that uses the Doors inter-process communication mechanism
might use the type "doors". The purpose of the name and type is to
identify providers in environments where there are multiple providers
installed.
AttachProvider implementations are loaded and instantiated at the first invocation of the providers method. This method attempts to load all provider implementations that are installed on the platform.
All of the methods in this class are safe for use by multiple
concurrent threads.
Since: 1.6
/**
* Attach provider class for attaching to a Java virtual machine.
*
* <p> An attach provider is a concrete subclass of this class that has a
* zero-argument constructor and implements the abstract methods specified
* below.
*
* <p> An attach provider implementation is typically tied to a Java virtual
* machine implementation, version, or even mode of operation. That is, a specific
* provider implementation will typically only be capable of attaching to
* a specific Java virtual machine implementation or version. For example, Oracle's
* JDK implementation ships with provider implementations that can only attach to
* Oracle's <i>HotSpot</i> virtual machine. In general, if an environment
* consists of Java virtual machines of different versions and from different
* vendors then there will be an attach provider implementation for each
* <i>family</i> of implementations or versions.
*
* <p> An attach provider is identified by its {@link #name <i>name</i>} and
* {@link #type <i>type</i>}. The <i>name</i> is typically, but not required to
* be, a name that corresponds to the VM vendor. The Oracle JDK implementation,
* for example, ships with attach providers that use the package name <i>"sun"</i>
* (for historical reasons). The
* <i>type</i> typically corresponds to the attach mechanism. For example, an
* implementation that uses the Doors inter-process communication mechanism
* might use the type <i>"doors"</i>. The purpose of the name and type is to
* identify providers in environments where there are multiple providers
* installed.
*
* <p> AttachProvider implementations are loaded and instantiated at the first
* invocation of the {@link #providers() providers} method. This method
* attempts to load all provider implementations that are installed on the
* platform.
*
* <p> All of the methods in this class are safe for use by multiple
* concurrent threads.
*
* @since 1.6
*/
public abstract class AttachProvider {
private static final Object lock = new Object();
private static List<AttachProvider> providers = null;
Initializes a new instance of this class.
Throws: - SecurityException – If a security manager has been installed and it denies
AttachPermission ("createAttachProvider")
/**
* Initializes a new instance of this class.
*
* @throws SecurityException
* If a security manager has been installed and it denies
* {@link com.sun.tools.attach.AttachPermission AttachPermission}
* ("{@code createAttachProvider}")
*/
protected AttachProvider() {
SecurityManager sm = System.getSecurityManager();
if (sm != null)
sm.checkPermission(new AttachPermission("createAttachProvider"));
}
Return this provider's name.
Returns: The name of this provider
/**
* Return this provider's name.
*
* @return The name of this provider
*/
public abstract String name();
Return this provider's type.
Returns: The type of this provider
/**
* Return this provider's type.
*
* @return The type of this provider
*/
public abstract String type();
Attaches to a Java virtual machine.
A Java virtual machine is identified by an abstract identifier. The
nature of this identifier is platform dependent but in many cases it will be the
string representation of the process identifier (or pid).
This method parses the identifier and maps the identifier to a Java virtual machine (in an implementation dependent manner). If the identifier cannot be parsed by the provider then an AttachNotSupportedException is thrown. Once parsed this method attempts to attach to the Java virtual machine. If the provider detects that the identifier corresponds to a Java virtual machine that does not exist, or it corresponds to a Java virtual machine that does not support the attach mechanism implemented by this provider, or it detects that the Java virtual machine is a version to which this provider cannot attach, then an AttachNotSupportedException is thrown.
Params: - id –
The abstract identifier that identifies the Java virtual machine.
Throws: - SecurityException – If a security manager has been installed and it denies
AttachPermission ("attachVirtualMachine"), or other permission required by the implementation. - AttachNotSupportedException –
If the identifier cannot be parsed, or it corresponds to
to a Java virtual machine that does not exist, or it
corresponds to a Java virtual machine which this
provider cannot attach.
- IOException –
If some other I/O error occurs
- NullPointerException – If
id is null
Returns: VirtualMachine representing the target virtual machine.
/**
* Attaches to a Java virtual machine.
*
* <p> A Java virtual machine is identified by an abstract identifier. The
* nature of this identifier is platform dependent but in many cases it will be the
* string representation of the process identifier (or pid).
*
* <p> This method parses the identifier and maps the identifier to a Java
* virtual machine (in an implementation dependent manner). If the identifier
* cannot be parsed by the provider then an
* {@link com.sun.tools.attach.AttachNotSupportedException AttachNotSupportedException}
* is thrown. Once parsed this method attempts to attach to the Java virtual machine.
* If the provider detects that the identifier corresponds to a Java virtual machine
* that does not exist, or it corresponds to a Java virtual machine that does not support
* the attach mechanism implemented by this provider, or it detects that the
* Java virtual machine is a version to which this provider cannot attach, then
* an {@code AttachNotSupportedException} is thrown.
*
* @param id
* The abstract identifier that identifies the Java virtual machine.
*
* @return VirtualMachine representing the target virtual machine.
*
* @throws SecurityException
* If a security manager has been installed and it denies
* {@link com.sun.tools.attach.AttachPermission AttachPermission}
* ("{@code attachVirtualMachine}"), or other permission
* required by the implementation.
*
* @throws AttachNotSupportedException
* If the identifier cannot be parsed, or it corresponds to
* to a Java virtual machine that does not exist, or it
* corresponds to a Java virtual machine which this
* provider cannot attach.
*
* @throws IOException
* If some other I/O error occurs
*
* @throws NullPointerException
* If {@code id} is {@code null}
*/
public abstract VirtualMachine attachVirtualMachine(String id)
throws AttachNotSupportedException, IOException;
Attaches to a Java virtual machine.
A Java virtual machine can be described using a VirtualMachineDescriptor. This method invokes the descriptor's provider() method to check that it is equal to this provider. It then attempts to attach to the Java virtual machine.
Params: - vmd –
The virtual machine descriptor
Throws: - SecurityException – If a security manager has been installed and it denies
AttachPermission ("attachVirtualMachine"), or other permission required by the implementation. - AttachNotSupportedException – If the descriptor's
provider() method returns a provider that is not this provider, or it does not correspond to a Java virtual machine to which this provider can attach. - IOException –
If some other I/O error occurs
- NullPointerException – If
vmd is null
Returns: VirtualMachine representing the target virtual machine.
/**
* Attaches to a Java virtual machine.
*
* <p> A Java virtual machine can be described using a
* {@link com.sun.tools.attach.VirtualMachineDescriptor VirtualMachineDescriptor}.
* This method invokes the descriptor's
* {@link com.sun.tools.attach.VirtualMachineDescriptor#provider() provider()} method
* to check that it is equal to this provider. It then attempts to attach to the
* Java virtual machine.
*
* @param vmd
* The virtual machine descriptor
*
* @return VirtualMachine representing the target virtual machine.
*
* @throws SecurityException
* If a security manager has been installed and it denies
* {@link com.sun.tools.attach.AttachPermission AttachPermission}
* ("{@code attachVirtualMachine}"), or other permission
* required by the implementation.
*
* @throws AttachNotSupportedException
* If the descriptor's
* {@link com.sun.tools.attach.VirtualMachineDescriptor#provider() provider()}
* method returns a provider that is not this provider, or it does not
* correspond to a Java virtual machine to which this provider can attach.
*
* @throws IOException
* If some other I/O error occurs
*
* @throws NullPointerException
* If {@code vmd} is {@code null}
*/
public VirtualMachine attachVirtualMachine(VirtualMachineDescriptor vmd)
throws AttachNotSupportedException, IOException
{
if (vmd.provider() != this) {
throw new AttachNotSupportedException("provider mismatch");
}
return attachVirtualMachine(vmd.id());
}
Lists the Java virtual machines known to this provider.
This method returns a list of VirtualMachineDescriptor elements. Each VirtualMachineDescriptor describes a Java virtual machine to which this provider can potentially attach. There isn't any guarantee that invoking attachVirtualMachine on each descriptor in the list will succeed.
Returns: The list of virtual machine descriptors which describe the
Java virtual machines known to this provider (may be empty).
/**
* Lists the Java virtual machines known to this provider.
*
* <p> This method returns a list of
* {@link com.sun.tools.attach.VirtualMachineDescriptor} elements. Each
* {@code VirtualMachineDescriptor} describes a Java virtual machine
* to which this provider can <i>potentially</i> attach. There isn't any
* guarantee that invoking
* {@link #attachVirtualMachine(VirtualMachineDescriptor) attachVirtualMachine}
* on each descriptor in the list will succeed.
*
* @return The list of virtual machine descriptors which describe the
* Java virtual machines known to this provider (may be empty).
*/
public abstract List<VirtualMachineDescriptor> listVirtualMachines();
Returns a list of the installed attach providers.
An AttachProvider is installed on the platform if:
- It is installed in a JAR file that is visible to the defining class loader of the AttachProvider type (usually, but not required to be, the
system
class loader).
- The JAR file contains a provider configuration named
com.sun.tools.attach.spi.AttachProvider in the resource directory META-INF/services.
- The provider configuration file lists the full-qualified class
name of the AttachProvider implementation.
The format of the provider configuration file is one fully-qualified class name per line. Space and tab characters surrounding each class name, as well as blank lines are ignored. The comment character is '#' (0x23), and on each line all characters following the first comment character are ignored. The file must be encoded in UTF-8.
AttachProvider implementations are loaded and instantiated
(using the zero-arg constructor) at the first invocation of this method.
The list returned by the first invocation of this method is the list
of providers. Subsequent invocations of this method return a list of the same
providers. The list is unmodifiable.
Returns: A list of the installed attach providers.
/**
* Returns a list of the installed attach providers.
*
* <p> An AttachProvider is installed on the platform if:
*
* <ul>
* <li>It is installed in a JAR file that is visible to the defining
* class loader of the AttachProvider type (usually, but not required
* to be, the {@link java.lang.ClassLoader#getSystemClassLoader system
* class loader}).</li>
*
* <li>The JAR file contains a provider configuration named
* {@code com.sun.tools.attach.spi.AttachProvider} in the resource directory
* {@code META-INF/services}.</li>
*
* <li>The provider configuration file lists the full-qualified class
* name of the AttachProvider implementation.</li>
* </ul>
*
* <p> The format of the provider configuration file is one fully-qualified
* class name per line. Space and tab characters surrounding each class name,
* as well as blank lines are ignored. The comment character is
* {@code '#'} ({@code 0x23}), and on each line all characters following
* the first comment character are ignored. The file must be encoded in
* UTF-8.
*
* <p> AttachProvider implementations are loaded and instantiated
* (using the zero-arg constructor) at the first invocation of this method.
* The list returned by the first invocation of this method is the list
* of providers. Subsequent invocations of this method return a list of the same
* providers. The list is unmodifiable.
*
* @return A list of the installed attach providers.
*/
public static List<AttachProvider> providers() {
synchronized (lock) {
if (providers == null) {
providers = new ArrayList<AttachProvider>();
ServiceLoader<AttachProvider> providerLoader =
ServiceLoader.load(AttachProvider.class,
AttachProvider.class.getClassLoader());
Iterator<AttachProvider> i = providerLoader.iterator();
while (i.hasNext()) {
try {
providers.add(i.next());
} catch (Throwable t) {
if (t instanceof ThreadDeath) {
ThreadDeath td = (ThreadDeath)t;
throw td;
}
// Log errors and exceptions since we cannot return them
t.printStackTrace();
}
}
}
return Collections.unmodifiableList(providers);
}
}
}