--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.rmi/share/classes/java/rmi/server/ObjID.java Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,248 @@
+/*
+ * Copyright (c) 1996, 2006, 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 java.rmi.server;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+import java.io.Serializable;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.SecureRandom;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * An <code>ObjID</code> is used to identify a remote object exported
+ * to an RMI runtime. When a remote object is exported, it is assigned
+ * an object identifier either implicitly or explicitly, depending on
+ * the API used to export.
+ *
+ * <p>The {@link #ObjID()} constructor can be used to generate a unique
+ * object identifier. Such an <code>ObjID</code> is unique over time
+ * with respect to the host it is generated on.
+ *
+ * The {@link #ObjID(int)} constructor can be used to create a
+ * "well-known" object identifier. The scope of a well-known
+ * <code>ObjID</code> depends on the RMI runtime it is exported to.
+ *
+ * <p>An <code>ObjID</code> instance contains an object number (of type
+ * <code>long</code>) and an address space identifier (of type
+ * {@link UID}). In a unique <code>ObjID</code>, the address space
+ * identifier is unique with respect to a given host over time. In a
+ * well-known <code>ObjID</code>, the address space identifier is
+ * equivalent to one returned by invoking the {@link UID#UID(short)}
+ * constructor with the value zero.
+ *
+ * <p>If the system property <code>java.rmi.server.randomIDs</code>
+ * is defined to equal the string <code>"true"</code> (case insensitive),
+ * then the {@link #ObjID()} constructor will use a cryptographically
+ * strong random number generator to choose the object number of the
+ * returned <code>ObjID</code>.
+ *
+ * @author Ann Wollrath
+ * @author Peter Jones
+ * @since 1.1
+ */
+public final class ObjID implements Serializable {
+
+ /** Object number for well-known <code>ObjID</code> of the registry. */
+ public static final int REGISTRY_ID = 0;
+
+ /** Object number for well-known <code>ObjID</code> of the activator. */
+ public static final int ACTIVATOR_ID = 1;
+
+ /**
+ * Object number for well-known <code>ObjID</code> of
+ * the distributed garbage collector.
+ */
+ public static final int DGC_ID = 2;
+
+ /** indicate compatibility with JDK 1.1.x version of class */
+ private static final long serialVersionUID = -6386392263968365220L;
+
+ private static final AtomicLong nextObjNum = new AtomicLong(0);
+ private static final UID mySpace = new UID();
+ private static final SecureRandom secureRandom = new SecureRandom();
+
+ /**
+ * @serial object number
+ * @see #hashCode
+ */
+ private final long objNum;
+
+ /**
+ * @serial address space identifier (unique to host over time)
+ */
+ private final UID space;
+
+ /**
+ * Generates a unique object identifier.
+ *
+ * <p>If the system property <code>java.rmi.server.randomIDs</code>
+ * is defined to equal the string <code>"true"</code> (case insensitive),
+ * then this constructor will use a cryptographically
+ * strong random number generator to choose the object number of the
+ * returned <code>ObjID</code>.
+ */
+ public ObjID() {
+ /*
+ * If generating random object numbers, create a new UID to
+ * ensure uniqueness; otherwise, use a shared UID because
+ * sequential object numbers already ensure uniqueness.
+ */
+ if (useRandomIDs()) {
+ space = new UID();
+ objNum = secureRandom.nextLong();
+ } else {
+ space = mySpace;
+ objNum = nextObjNum.getAndIncrement();
+ }
+ }
+
+ /**
+ * Creates a "well-known" object identifier.
+ *
+ * <p>An <code>ObjID</code> created via this constructor will not
+ * clash with any <code>ObjID</code>s generated via the no-arg
+ * constructor.
+ *
+ * @param objNum object number for well-known object identifier
+ */
+ public ObjID(int objNum) {
+ space = new UID((short) 0);
+ this.objNum = objNum;
+ }
+
+ /**
+ * Constructs an object identifier given data read from a stream.
+ */
+ private ObjID(long objNum, UID space) {
+ this.objNum = objNum;
+ this.space = space;
+ }
+
+ /**
+ * Marshals a binary representation of this <code>ObjID</code> to
+ * an <code>ObjectOutput</code> instance.
+ *
+ * <p>Specifically, this method first invokes the given stream's
+ * {@link ObjectOutput#writeLong(long)} method with this object
+ * identifier's object number, and then it writes its address
+ * space identifier by invoking its {@link UID#write(DataOutput)}
+ * method with the stream.
+ *
+ * @param out the <code>ObjectOutput</code> instance to write
+ * this <code>ObjID</code> to
+ *
+ * @throws IOException if an I/O error occurs while performing
+ * this operation
+ */
+ public void write(ObjectOutput out) throws IOException {
+ out.writeLong(objNum);
+ space.write(out);
+ }
+
+ /**
+ * Constructs and returns a new <code>ObjID</code> instance by
+ * unmarshalling a binary representation from an
+ * <code>ObjectInput</code> instance.
+ *
+ * <p>Specifically, this method first invokes the given stream's
+ * {@link ObjectInput#readLong()} method to read an object number,
+ * then it invokes {@link UID#read(DataInput)} with the
+ * stream to read an address space identifier, and then it
+ * creates and returns a new <code>ObjID</code> instance that
+ * contains the object number and address space identifier that
+ * were read from the stream.
+ *
+ * @param in the <code>ObjectInput</code> instance to read
+ * <code>ObjID</code> from
+ *
+ * @return unmarshalled <code>ObjID</code> instance
+ *
+ * @throws IOException if an I/O error occurs while performing
+ * this operation
+ */
+ public static ObjID read(ObjectInput in) throws IOException {
+ long num = in.readLong();
+ UID space = UID.read(in);
+ return new ObjID(num, space);
+ }
+
+ /**
+ * Returns the hash code value for this object identifier, the
+ * object number.
+ *
+ * @return the hash code value for this object identifier
+ */
+ public int hashCode() {
+ return (int) objNum;
+ }
+
+ /**
+ * Compares the specified object with this <code>ObjID</code> for
+ * equality.
+ *
+ * This method returns <code>true</code> if and only if the
+ * specified object is an <code>ObjID</code> instance with the same
+ * object number and address space identifier as this one.
+ *
+ * @param obj the object to compare this <code>ObjID</code> to
+ *
+ * @return <code>true</code> if the given object is equivalent to
+ * this one, and <code>false</code> otherwise
+ */
+ public boolean equals(Object obj) {
+ if (obj instanceof ObjID) {
+ ObjID id = (ObjID) obj;
+ return objNum == id.objNum && space.equals(id.space);
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * Returns a string representation of this object identifier.
+ *
+ * @return a string representation of this object identifier
+ */
+ /*
+ * The address space identifier is only included in the string
+ * representation if it does not denote the local address space
+ * (or if the randomIDs property was set).
+ */
+ public String toString() {
+ return "[" + (space.equals(mySpace) ? "" : space + ", ") +
+ objNum + "]";
+ }
+
+ private static boolean useRandomIDs() {
+ String value = AccessController.doPrivileged(
+ (PrivilegedAction<String>) () -> System.getProperty("java.rmi.server.randomIDs"));
+ return value == null ? true : Boolean.parseBoolean(value);
+ }
+}