summaryrefslogtreecommitdiff
path: root/libjava/classpath/java/rmi/dgc/VMID.java
diff options
context:
space:
mode:
authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/rmi/dgc/VMID.java
downloadcbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.bz2
cbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.xz
obtained gcc-4.6.4.tar.bz2 from upstream website;upstream
verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository.
Diffstat (limited to 'libjava/classpath/java/rmi/dgc/VMID.java')
-rw-r--r--libjava/classpath/java/rmi/dgc/VMID.java191
1 files changed, 191 insertions, 0 deletions
diff --git a/libjava/classpath/java/rmi/dgc/VMID.java b/libjava/classpath/java/rmi/dgc/VMID.java
new file mode 100644
index 000000000..925c1bfb1
--- /dev/null
+++ b/libjava/classpath/java/rmi/dgc/VMID.java
@@ -0,0 +1,191 @@
+/* VMID.java -- The object ID, unique between all virtual machines.
+ Copyright (c) 1996, 1997, 1998, 1999, 2006 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+package java.rmi.dgc;
+
+import gnu.java.lang.CPStringBuilder;
+
+import java.io.Serializable;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.rmi.server.UID;
+import java.util.Arrays;
+
+/**
+ * An identifier that is unique accross the all virtual machines. This class is
+ * used by distributed garbage collector to identify the virtual machine of
+ * the client, but may also be used in various other cases, when such identifier
+ * is required. This class separately stores and transfers the host IP
+ * address, but will try to do its best also for the case if it failed to
+ * determine it. The alternative algorithms are used in {@link UID} that is
+ * part of this class. The VMID's, created on the same host, but in the two
+ * separately (parallely) running virtual machines are different.
+ */
+public final class VMID implements Serializable
+{
+ /**
+ * Use SVUID for interoperability.
+ */
+ static final long serialVersionUID = -538642295484486218L;
+
+ /**
+ * If true, the IP of this host can ve reliably determined.
+ */
+ static boolean areWeUnique;
+
+ /**
+ * The IP address of the local host.
+ */
+ static byte[] localAddr;
+
+ /**
+ * The IP address of the local host.
+ */
+ private byte[] addr;
+
+ /**
+ * The cached hash code.
+ */
+ transient int hash;
+
+ /**
+ * The UID of this VMID.
+ */
+ private UID uid;
+
+ static
+ {
+ // This "local host" value usually indicates that the local
+ // IP address cannot be reliably determined.
+ byte[] localHost = new byte[] { 127, 0, 0, 1 };
+
+ try
+ {
+ localAddr = InetAddress.getLocalHost().getAddress();
+ areWeUnique = !Arrays.equals(localHost, localAddr);
+ }
+ catch (UnknownHostException uhex)
+ {
+ localAddr = localHost;
+ areWeUnique = false;
+ }
+ }
+
+ /**
+ * Create the new VMID. All VMID's are unique accross tha all virtual
+ * machines.
+ */
+ public VMID()
+ {
+ addr = localAddr;
+ uid = new UID();
+ }
+
+ /**
+ * Return true if it is possible to get the accurate address of this host.
+ * If false is returned, the created VMID's are less reliable, but the
+ * starting time and possibly the memory allocation are also taken into
+ * consideration in the incorporated UID. Hence the VMID's, created on the
+ * different virtual machines, still should be different.
+ *
+ * @deprecated VMID's are more or less always reliable.
+ *
+ * @return false if the local host ip address is 127.0.0.1 or unknown,
+ * true otherwise.
+ */
+ public static boolean isUnique ()
+ {
+ return areWeUnique;
+ }
+
+ /**
+ * Get the hash code of this VMID.
+ */
+ public int hashCode ()
+ {
+ if (hash==0)
+ {
+ for (int i = 0; i < localAddr.length; i++)
+ hash += addr[i];
+ hash = hash ^ uid.hashCode();
+ }
+ return hash;
+ }
+
+ /**
+ * Returns true if the passed parameter is also VMID and it is equal to this
+ * VMID. The VMID should only be equal to itself (also if the passed value is
+ * another instance, cloned by serialization).
+ */
+ public boolean equals(Object obj)
+ {
+ if (obj instanceof VMID)
+ {
+ VMID other = (VMID) obj;
+
+ // The UID's are compared faster than arrays.
+ return uid.equals(other.uid) && Arrays.equals(addr, other.addr);
+ }
+ else
+ return false;
+
+ }
+
+ /**
+ * Get the string representation of this VMID.
+ */
+ public String toString ()
+ {
+ CPStringBuilder buf = new CPStringBuilder ("[VMID: ");
+
+ for (int i = 0; i < addr.length; i++)
+ {
+ if (i > 0)
+ {
+ buf.append (".");
+ }
+
+ buf.append (Integer.toString (addr [i]));
+ }
+
+ buf.append (" ");
+ buf.append (uid.toString ());
+ buf.append ("]");
+
+ return buf.toString();
+ }
+}