I'm not checking this in yet -- I would like comments first. I happened to run across the caching code in java.net.InetAddress today. We had a couple discussions about this already in the past, e.g. one is here:
http://gcc.gnu.org/ml/java/2000-04/msg00106.html I still think this code is incorrect, as it doesn't respect TTL properly. I would like to remove it, which is what this patch does. Comments? Tom 2006-01-11 Tom Tromey <[EMAIL PROTECTED]> * java/net/InetAddress.java (DEFAULT_CACHE_SIZE): Removed. (DEFAULT_CACHE_PERIOD, DEFAULT_CACHE_PURGE_PCT): Likewise. (cache_size, cache_period, cache_purge_pct, cache): Likewise. (static initializer): Removed cache code. (checkCacheFor, addToCache): Removed. (getAllByName): Removed cache code. (lookup_time): Removed. (InetAddress): Updated. Index: java/net/InetAddress.java =================================================================== RCS file: /cvsroot/classpath/classpath/java/net/InetAddress.java,v retrieving revision 1.44 diff -u -r1.44 InetAddress.java --- java/net/InetAddress.java 9 Jan 2006 18:39:22 -0000 1.44 +++ java/net/InetAddress.java 11 Jan 2006 21:08:17 -0000 @@ -43,7 +43,6 @@ import java.io.ObjectOutputStream; import java.io.ObjectStreamException; import java.io.Serializable; -import java.util.HashMap; import java.util.StringTokenizer; /** @@ -66,22 +65,6 @@ private static final long serialVersionUID = 3286316764910316507L; /** - * The default DNS hash table size, - * Use a prime number happy with hash table. - */ - private static final int DEFAULT_CACHE_SIZE = 89; - - /** - * The default caching period in minutes. - */ - private static final int DEFAULT_CACHE_PERIOD = 4 * 60; - - /** - * Percentage of cache entries to purge when the table gets full. - */ - private static final int DEFAULT_CACHE_PURGE_PCT = 30; - - /** * The special IP address INADDR_ANY. */ private static InetAddress inaddr_any; @@ -96,50 +79,8 @@ */ static InetAddress LOCALHOST; - /** - * The size of the cache. - */ - private static int cache_size = 0; - - /** - * The length of time we will continue to read the address from cache - * before forcing another lookup. - */ - private static int cache_period = 0; - - /** - * What percentage of the cache we will purge if it gets full. - */ - private static int cache_purge_pct = 0; - - /** - * HashMap to use as DNS lookup cache. - * Use HashMap because all accesses to cache are already synchronized. - */ - private static HashMap cache; - static { - // Look for properties that override default caching behavior - cache_size = - Integer.getInteger("gnu.java.net.dns_cache_size", DEFAULT_CACHE_SIZE) - .intValue(); - cache_period = - Integer.getInteger("gnu.java.net.dns_cache_period", - DEFAULT_CACHE_PERIOD * 60 * 1000).intValue(); - - cache_purge_pct = - Integer.getInteger("gnu.java.net.dns_cache_purge_pct", - DEFAULT_CACHE_PURGE_PCT).intValue(); - - // Fallback to defaults if necessary - if ((cache_purge_pct < 1) || (cache_purge_pct > 100)) - cache_purge_pct = DEFAULT_CACHE_PURGE_PCT; - - // Create the cache - if (cache_size != 0) - cache = new HashMap(cache_size); - // precompute the ANY_IF address try { @@ -174,11 +115,6 @@ String hostName; /** - * The time this address was looked up. - */ - transient long lookup_time; - - /** * The field 'family' seems to be the AF_ value. * FIXME: Much of the code in the other java.net classes does not make * use of this family field. A better implementation would be to make @@ -200,8 +136,6 @@ addr = (null == ipaddr) ? null : (byte[]) ipaddr.clone(); hostName = hostname; - lookup_time = System.currentTimeMillis(); - family = 2; /* AF_INET */ } @@ -660,12 +594,6 @@ return addresses; } - // Check the cache for this host before doing a lookup - addresses = checkCacheFor(hostname); - - if (addresses != null) - return addresses; - // Not in cache, try the lookup byte[][] iplist = VMInetAddress.getHostByName(hostname); @@ -682,71 +610,10 @@ addresses[i] = new Inet4Address(iplist[i], hostname); } - addToCache(hostname, addresses); return addresses; } /** - * This method checks the DNS cache to see if we have looked this hostname - * up before. If so, we return the cached addresses unless it has been in the - * cache too long. - * - * @param hostname The hostname to check for - * - * @return The InetAddress for this hostname or null if not available - */ - private static synchronized InetAddress[] checkCacheFor(String hostname) - { - InetAddress[] addresses = null; - - if (cache_size == 0) - return null; - - Object obj = cache.get(hostname); - if (obj == null) - return null; - - if (obj instanceof InetAddress[]) - addresses = (InetAddress[]) obj; - - if (addresses == null) - return null; - - if (cache_period != -1) - if ((System.currentTimeMillis() - addresses[0].lookup_time) > cache_period) - { - cache.remove(hostname); - return null; - } - - return addresses; - } - - /** - * This method adds an InetAddress object to our DNS cache. Note that - * if the cache is full, then we run a purge to get rid of old entries. - * This will cause a performance hit, thus applications using lots of - * lookups should set the cache size to be very large. - * - * @param hostname The hostname to cache this address under - * @param obj The InetAddress or InetAddress array to store - */ - private static synchronized void addToCache(String hostname, Object obj) - { - if (cache_size == 0) - return; - - // Check to see if hash table is full - if (cache_size != -1) - if (cache.size() == cache_size) - { - // FIXME Add code to purge later. - } - - cache.put(hostname, obj); - } - - /** * Returns the special address INADDR_ANY used for binding to a local * port on all IP addresses hosted by a the local host. * _______________________________________________ Classpath-patches mailing list Classpath-patches@gnu.org http://lists.gnu.org/mailman/listinfo/classpath-patches
