aboutsummaryrefslogtreecommitdiff
path: root/libjava/classpath/java/rmi/dgc/VMID.java
diff options
context:
space:
mode:
authorMark Wielaard <mark@gcc.gnu.org>2006-05-18 17:29:21 +0000
committerMark Wielaard <mark@gcc.gnu.org>2006-05-18 17:29:21 +0000
commit4f9533c7722fa07511a94d005227961f4a4dec23 (patch)
tree9f9c470de62ee62fba1331a396450d728d2b1fad /libjava/classpath/java/rmi/dgc/VMID.java
parenteaec4980e139903ae9b274d1abcf3a13946603a8 (diff)
downloadgcc-4f9533c7722fa07511a94d005227961f4a4dec23.zip
gcc-4f9533c7722fa07511a94d005227961f4a4dec23.tar.gz
gcc-4f9533c7722fa07511a94d005227961f4a4dec23.tar.bz2
Imported GNU Classpath 0.90
Imported GNU Classpath 0.90 * scripts/makemake.tcl: LocaleData.java moved to gnu/java/locale. * sources.am: Regenerated. * gcj/javaprims.h: Regenerated. * Makefile.in: Regenerated. * gcj/Makefile.in: Regenerated. * include/Makefile.in: Regenerated. * testsuite/Makefile.in: Regenerated. * gnu/java/lang/VMInstrumentationImpl.java: New override. * gnu/java/net/local/LocalSocketImpl.java: Likewise. * gnu/classpath/jdwp/VMMethod.java: Likewise. * gnu/classpath/jdwp/VMVirtualMachine.java: Update to latest interface. * java/lang/Thread.java: Add UncaughtExceptionHandler. * java/lang/reflect/Method.java: Implements GenericDeclaration and isSynthetic(), * java/lang/reflect/Field.java: Likewise. * java/lang/reflect/Constructor.java * java/lang/Class.java: Implements Type, GenericDeclaration, getSimpleName() and getEnclosing*() methods. * java/lang/Class.h: Add new public methods. * java/lang/Math.java: Add signum(), ulp() and log10(). * java/lang/natMath.cc (log10): New function. * java/security/VMSecureRandom.java: New override. * java/util/logging/Logger.java: Updated to latest classpath version. * java/util/logging/LogManager.java: New override. From-SVN: r113887
Diffstat (limited to 'libjava/classpath/java/rmi/dgc/VMID.java')
-rw-r--r--libjava/classpath/java/rmi/dgc/VMID.java139
1 files changed, 95 insertions, 44 deletions
diff --git a/libjava/classpath/java/rmi/dgc/VMID.java b/libjava/classpath/java/rmi/dgc/VMID.java
index f960d9c..dc989c2 100644
--- a/libjava/classpath/java/rmi/dgc/VMID.java
+++ b/libjava/classpath/java/rmi/dgc/VMID.java
@@ -1,5 +1,5 @@
-/* VMID.java
- Copyright (c) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+/* 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.
@@ -41,37 +41,72 @@ 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;
- static final boolean areWeUnique;
+ /**
+ * 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
- {
- byte[] addr;
- boolean awu = true;
- try {
- addr = InetAddress.getLocalHost().getAddress();
- if (addr[0] == 127 && addr[1] == 0 && addr[2] == 0 && addr[3] == 1) {
- awu = false;
- }
- }
- catch (UnknownHostException _) {
- addr = new byte[]{ 127, 0, 0, 1 };
- awu = false;
+ {
+ // 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;
+ }
}
- localAddr = addr;
- areWeUnique = awu;
- }
-
+
+ /**
+ * Create the new VMID. All VMID's are unique accross tha all virtual
+ * machines.
+ */
public VMID()
{
addr = localAddr;
@@ -79,42 +114,58 @@ public final class VMID implements Serializable
}
/**
- * @deprecated
+ * 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 ()
{
- return super.hashCode();
- }
-
- public boolean equals (Object obj)
- {
- if (!(obj instanceof VMID))
- {
- return false;
- }
-
- VMID other = (VMID) obj;
- if (addr.length != other.addr.length)
+ if (hash==0)
{
- return false;
+ for (int i = 0; i < localAddr.length; i++)
+ hash += addr[i];
+ hash = hash ^ uid.hashCode();
}
-
- for (int i = addr.length - 1; i >= 0; i--)
+ 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)
{
- if (addr[i] != other.addr[i])
- {
- return false;
- }
+ VMID other = (VMID) obj;
+
+ // The UID's are compared faster than arrays.
+ return uid.equals(other.uid) && Arrays.equals(addr, other.addr);
}
-
- return uid.equals(other.uid);
- }
+ else
+ return false;
+ }
+
+ /**
+ * Get the string representation of this VMID.
+ */
public String toString ()
{
StringBuffer buf = new StringBuffer ("[VMID: ");