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1 files changed, 219 insertions, 0 deletions

diff --git a/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EOTemporaryGlobalID.java b/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EOTemporaryGlobalID.java
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+++ b/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EOTemporaryGlobalID.java
@@ -0,0 +1,219 @@
+/*
+Wotonomy: OpenStep design patterns for pure Java applications.
+Copyright (C) 2001 Intersect Software Corporation
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library 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
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, see http://www.gnu.org
+*/
+
+package net.wotonomy.control;
+
+import java.net.InetAddress;
+
+/**
+* EOTemporaryGlobalID is a network-wide unique key.
+* This is used by EOEditingContext to construct temporary
+* ids when new objects are created.  <br><br>
+*
+* The specified format of the key is a byte array: 
+* &lt; Sequence [2], ProcessID [2], Time [4], IP Addr [4] &gt;,
+* but because java does not allow access to the process id,
+* the timestamp of when this class is first loaded is used
+* to simulate a process id.
+* 
+*
+* @author michael@mpowers.net
+* @author $Author: cgruber $
+* @version $Revision: 893 $
+*/
+public class EOTemporaryGlobalID 
+    extends EOGlobalID 
+{
+    /**
+    * Holds the length in bytes of the key that is generated.
+    */
+    public static final int UniqueBinaryKeyLength = 12;
+    
+    private static int sequence;
+    private static byte[] processid; // 2 bytes
+    private static byte[] ipaddr; // 4 bytes
+    
+    static // static initializer
+    {
+        // init sequence
+        sequence = 0;
+        
+        // init processid
+        processid = new byte[2];
+        long time = System.currentTimeMillis();
+        processid[1] = (byte) time;
+        time = time >> 8;
+        processid[0] = (byte) time;
+
+        // init ipaddr
+        ipaddr = new byte[4];
+        try
+        {
+            ipaddr = InetAddress.getLocalHost().getAddress();
+        }
+        catch ( Exception exc )
+        {
+            // could not obtain ip address - use pid twice
+            ipaddr[0] = processid[0];
+            ipaddr[1] = processid[1];
+            ipaddr[2] = processid[0];
+            ipaddr[3] = processid[1];
+        }
+    }
+    
+    private byte[] key;
+    private int hashCode;
+
+    /**
+    * Generates a new id with a unique key.
+    */    
+    public EOTemporaryGlobalID()
+    {
+        key = new byte[UniqueBinaryKeyLength];
+        
+        // init sequence (important byte first)
+        key[0] = (byte) ( sequence ); 
+        key[1] = (byte) ( sequence >> 8 );
+        sequence++;
+        
+        // populate pid (important byte first)
+        key[2] = processid[1];
+        key[3] = processid[0];
+        
+        // init time (important byte first)
+        long time = System.currentTimeMillis();
+        key[4] = (byte) time;
+        time = time >> 8;
+        key[5] = (byte) time;
+        time = time >> 8;
+        key[6] = (byte) time;
+        time = time >> 8;
+        key[7] = (byte) time;
+        
+        // populate ipaddr
+        key[8]  = ipaddr[0];
+        key[9]  = ipaddr[1];
+        key[10] = ipaddr[2];
+        key[11] = ipaddr[3];
+
+        // use string's hash code
+        hashCode = new String( key ).hashCode();
+    }
+    
+    /**
+    * Private constructor for cloning.
+    */
+    private EOTemporaryGlobalID( byte[] aKey )
+    {
+//        key = aKey; // this might be faster
+
+        // make copy of key - might be safer
+        key = new byte[ UniqueBinaryKeyLength ];
+        for ( int i = 0; i < UniqueBinaryKeyLength; i++ )
+        {
+            key[i] = aKey[i];
+        }
+        
+        // use string's hash code
+        hashCode = new String( aKey ).hashCode();
+    }
+    
+    /**
+    * Returns true.
+    */
+    public boolean isTemporary()
+    {
+        return true;   
+    }
+    
+    /**
+    * Returns whether the keys are equal.
+    */
+    public boolean equals( Object anObject )
+    {
+        if ( ! ( anObject instanceof EOTemporaryGlobalID ) ) 
+            return false;   
+        
+        byte[] otherKey = ((EOTemporaryGlobalID)anObject).key;
+        
+        for ( int i = 0; i < UniqueBinaryKeyLength; i++ )
+        {
+            if ( key[i] != otherKey[i] ) return false;
+        }
+        return true;
+    }
+    
+    /**
+    * Returns a copy of this object.
+    */
+    public Object clone()
+    {
+        // faster than super.clone()
+        return new EOTemporaryGlobalID( key );
+    }
+    
+    public int hashCode()
+    {
+        return hashCode;           
+    }
+    
+    /**
+    * Returns a string representation of this key.
+    * This is a 24-character string with each pair
+    * of characters holding a hexadecimal value that
+    * is 128 more than the value of the corresponding 
+    * byte (to account for two's complement).
+    */
+    public String toString()
+    {
+        String hex;
+        StringBuffer buffer = new StringBuffer();
+        for ( int i = 0; i < key.length; i++ )
+        {
+            // get string: adjust for two's complement
+            hex = Integer.toHexString( key[i]+128 );
+            // pad with zero so we take two characters
+            if ( hex.length() == 1 ) hex = "0" + hex;
+            // append hex code
+            buffer.append( hex );
+        }
+        return buffer.toString();
+    }
+}
+
+/*
+ * $Log$
+ * Revision 1.1  2006/02/16 13:19:57  cgruber
+ * Check in all sources in eclipse-friendly maven-enabled packages.
+ *
+ * Revision 1.4  2001/04/29 22:02:45  mpowers
+ * Work on id transposing between editing contexts.
+ *
+ * Revision 1.3  2001/02/15 21:13:30  mpowers
+ * First draft implementation is complete.  Now on to debugging.
+ *
+ * Revision 1.2  2001/02/14 23:03:02  mpowers
+ * A near-complete first draft of EOEditingContext.
+ *
+ * Revision 1.1  2001/02/13 23:24:29  mpowers
+ * Implementing more of editing context.
+ *
+ *
+ */
+    
+