The ActivationGroupDesc.java Java example source code
/*
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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.
*
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package java.rmi.activation;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.rmi.MarshalledObject;
import java.util.Arrays;
import java.util.Properties;
/**
* An activation group descriptor contains the information necessary to
* create/recreate an activation group in which to activate objects.
* Such a descriptor contains: <ul>
* <li> the group's class name,
* <li> the group's code location (the location of the group's class), and
* <li> a "marshalled" object that can contain group specific
* initialization data. </ul>
*
* The group's class must be a concrete subclass of
* <code>ActivationGroup. A subclass of
* <code>ActivationGroup is created/recreated via the
* <code>ActivationGroup.createGroup static method that invokes
* a special constructor that takes two arguments: <ul>
*
* <li> the group's ActivationGroupID, and
* <li> the group's initialization data (in a
* <code>java.rmi.MarshalledObject)
*
* @author Ann Wollrath
* @since 1.2
* @see ActivationGroup
* @see ActivationGroupID
*/
public final class ActivationGroupDesc implements Serializable {
/**
* @serial The group's fully package qualified class name.
*/
private String className;
/**
* @serial The location from where to load the group's class.
*/
private String location;
/**
* @serial The group's initialization data.
*/
private MarshalledObject<?> data;
/**
* @serial The controlling options for executing the VM in
* another process.
*/
private CommandEnvironment env;
/**
* @serial A properties map which will override those set
* by default in the subprocess environment.
*/
private Properties props;
/** indicate compatibility with the Java 2 SDK v1.2 version of class */
private static final long serialVersionUID = -4936225423168276595L;
/**
* Constructs a group descriptor that uses the system defaults for group
* implementation and code location. Properties specify Java
* environment overrides (which will override system properties in
* the group implementation's VM). The command
* environment can control the exact command/options used in
* starting the child VM, or can be <code>null to accept
* rmid's default.
*
* <p>This constructor will create an ActivationGroupDesc
* with a <code>null group class name, which indicates the system's
* default <code>ActivationGroup implementation.
*
* @param overrides the set of properties to set when the group is
* recreated.
* @param cmd the controlling options for executing the VM in
* another process (or <code>null).
* @since 1.2
*/
public ActivationGroupDesc(Properties overrides,
CommandEnvironment cmd)
{
this(null, null, null, overrides, cmd);
}
/**
* Specifies an alternate group implementation and execution
* environment to be used for the group.
*
* @param className the group's package qualified class name or
* <code>null. A null group class name indicates
* the system's default <code>ActivationGroup implementation.
* @param location the location from where to load the group's
* class
* @param data the group's initialization data contained in
* marshalled form (could contain properties, for example)
* @param overrides a properties map which will override those set
* by default in the subprocess environment (will be translated
* into <code>-D options), or null.
* @param cmd the controlling options for executing the VM in
* another process (or <code>null).
* @since 1.2
*/
public ActivationGroupDesc(String className,
String location,
MarshalledObject<?> data,
Properties overrides,
CommandEnvironment cmd)
{
this.props = overrides;
this.env = cmd;
this.data = data;
this.location = location;
this.className = className;
}
/**
* Returns the group's class name (possibly <code>null). A
* <code>null group class name indicates the system's default
* <code>ActivationGroup implementation.
* @return the group's class name
* @since 1.2
*/
public String getClassName() {
return className;
}
/**
* Returns the group's code location.
* @return the group's code location
* @since 1.2
*/
public String getLocation() {
return location;
}
/**
* Returns the group's initialization data.
* @return the group's initialization data
* @since 1.2
*/
public MarshalledObject<?> getData() {
return data;
}
/**
* Returns the group's property-override list.
* @return the property-override list, or <code>null
* @since 1.2
*/
public Properties getPropertyOverrides() {
return (props != null) ? (Properties) props.clone() : null;
}
/**
* Returns the group's command-environment control object.
* @return the command-environment object, or <code>null
* @since 1.2
*/
public CommandEnvironment getCommandEnvironment() {
return this.env;
}
/**
* Startup options for ActivationGroup implementations.
*
* This class allows overriding default system properties and
* specifying implementation-defined options for ActivationGroups.
* @since 1.2
*/
public static class CommandEnvironment implements Serializable {
private static final long serialVersionUID = 6165754737887770191L;
/**
* @serial
*/
private String command;
/**
* @serial
*/
private String[] options;
/**
* Create a CommandEnvironment with all the necessary
* information.
*
* @param cmdpath the name of the java executable, including
* the full path, or <code>null, meaning "use rmid's default".
* The named program <em>must be able to accept multiple
* <code>-Dpropname=value options (as documented for the
* "java" tool)
*
* @param argv extra options which will be used in creating the
* ActivationGroup. Null has the same effect as an empty
* list.
* @since 1.2
*/
public CommandEnvironment(String cmdpath,
String[] argv)
{
this.command = cmdpath; // might be null
// Hold a safe copy of argv in this.options
if (argv == null) {
this.options = new String[0];
} else {
this.options = new String[argv.length];
System.arraycopy(argv, 0, this.options, 0, argv.length);
}
}
/**
* Fetch the configured path-qualified java command name.
*
* @return the configured name, or <code>null if configured to
* accept the default
* @since 1.2
*/
public String getCommandPath() {
return (this.command);
}
/**
* Fetch the configured java command options.
*
* @return An array of the command options which will be passed
* to the new child command by rmid.
* Note that rmid may add other options before or after these
* options, or both.
* Never returns <code>null.
* @since 1.2
*/
public String[] getCommandOptions() {
return options.clone();
}
/**
* Compares two command environments for content equality.
*
* @param obj the Object to compare with
* @return true if these Objects are equal; false otherwise.
* @see java.util.Hashtable
* @since 1.2
*/
public boolean equals(Object obj) {
if (obj instanceof CommandEnvironment) {
CommandEnvironment env = (CommandEnvironment) obj;
return
((command == null ? env.command == null :
command.equals(env.command)) &&
Arrays.equals(options, env.options));
} else {
return false;
}
}
/**
* Return identical values for similar
* <code>CommandEnvironments.
* @return an integer
* @see java.util.Hashtable
*/
public int hashCode()
{
// hash command and ignore possibly expensive options
return (command == null ? 0 : command.hashCode());
}
/**
* <code>readObject for custom serialization.
*
* <p>This method reads this object's serialized form for this
* class as follows:
*
* <p>This method first invokes defaultReadObject on
* the specified object input stream, and if <code>options
* is <code>null, then options is set to a
* zero-length array of <code>String.
*/
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
in.defaultReadObject();
if (options == null) {
options = new String[0];
}
}
}
/**
* Compares two activation group descriptors for content equality.
*
* @param obj the Object to compare with
* @return true if these Objects are equal; false otherwise.
* @see java.util.Hashtable
* @since 1.2
*/
public boolean equals(Object obj) {
if (obj instanceof ActivationGroupDesc) {
ActivationGroupDesc desc = (ActivationGroupDesc) obj;
return
((className == null ? desc.className == null :
className.equals(desc.className)) &&
(location == null ? desc.location == null :
location.equals(desc.location)) &&
(data == null ? desc.data == null : data.equals(desc.data)) &&
(env == null ? desc.env == null : env.equals(desc.env)) &&
(props == null ? desc.props == null :
props.equals(desc.props)));
} else {
return false;
}
}
/**
* Produce identical numbers for similar <code>ActivationGroupDescs.
* @return an integer
* @see java.util.Hashtable
*/
public int hashCode() {
// hash location, className, data, and env
// but omit props (may be expensive)
return ((location == null
? 0
: location.hashCode() << 24) ^
(env == null
? 0
: env.hashCode() << 16) ^
(className == null
? 0
: className.hashCode() << 8) ^
(data == null
? 0
: data.hashCode()));
}
}
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