created mirror

Java/p2p/P2PStorage.java

@@ -0,0 +1,82 @@
+/*   
+P2PStorage.java
+ *    
+ *    Copyright (c) 2001, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software 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 README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Tuomas Lukka
+ */
+
+package org.gzigzag.p2p;
+
+/** The physical layers of the mediaserver p2p layer.
+ * This is a mechanism layer; no policy is included here.
+ * For example, uncache unconditionally deletes the given span
+ * from the cache. Higher-up levels are expected to make e.g. reference
+ * counting functionality available to yet higher levels.
+ * <p>
+ * This level simply associates unique ids to permanent, immutable
+ * blocks of bits: the important invariant is that 
+ * get(id, offs, len) always returns either the same bits or
+ * an error if the bits are unobtainable at that time.
+ * <p>
+ * Later on, digital signature functionality will be provided 
+ * to help this.
+ */
+
+interface P2PStorage {
+public static final String rcsid = "$Id: P2PStorage.java,v 1.2 2001/04/02 17:23:44 tjl Exp $";
+
+   /** Convert a string to a unique id object.
+    */
+   UniqueID str2id(String s);
+
+   /** Get the length of the bits pointed to by the given id.
+    */
+   long length(UniqueID id);
+
+   /** Get the given bytes from the given id.
+    */
+   byte[] get(UniqueID id, long offs, long len);
+
+   /** Get an input stream from the given id.
+    */
+   java.io.InputStream getInputStream(UniqueID id, long offs, long len);
+
+   /** Store the given span in the cache.
+    */
+   void cache(UniqueID id, long offs, long len);
+
+   /** Remove the given span from the cache.
+    */
+   void uncache(UniqueID id, long offs, long len);
+
+   /** A structure showing a single cached entry.
+    */
+   class InCache {
+      UniqueID id;
+      long offs, len;
+   }
+   /** Get a listing of the local cache/storage.
+    */
+   InCache[] getDirectory();
+
+   /** Create a new globally unique id that can then be written to.
+    */
+   UniqueID.Writable newUniqueID();
+}
+

Java/p2p/UniqueID.java

@@ -0,0 +1,54 @@
+/*   
+UniqueID.java
+ *    
+ *    Copyright (c) 2001, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software 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 README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Tuomas Lukka
+ */
+
+package org.gzigzag.p2p;
+
+/** A unique bit-block identifier. 
+ * These identifiers are supposed to be globally unique and
+ * identify a single, continuous block of bits.
+ * @see Phys
+ */
+
+interface UniqueID {
+public static final String rcsid = "$Id: UniqueID.java,v 1.2 2001/04/02 17:23:44 tjl Exp $";
+
+   /** A simple representation of the whole ID as a string.
+    * Phys.str2id(s) is the inverse.
+    */
+   String toString();
+
+   /** A writable version.
+    */
+   interface Writable extends UniqueID {
+       /** Get a stream for writing into the object
+	* represented by this unique id.
+	* Naturally, this is only usable once; calling
+	* it more than once results in an exception.
+	* Closing the stream finalizes the object - 
+	* it's not visible anywhere prior to that.
+  	*/
+       java.io.OutputStream getOutputStream();
+   }
+}
+
+