Factor out the canonical order generation as we'll still need this for the

static newKey() methods even if we revamp this whole business.

src/java/com/samskivert/depot/Key.java

@@ -128,50 +128,7 @@ public class Key<T extends PersistentRecord> extends WhereClause
      */
     public Key (Class<T> pClass, ColumnExp[] fields, Comparable<?>[] values)
     {
-        if (fields.length != values.length) {
+        this(pClass, toCanonicalOrder(pClass, fields, values));
-            throw new IllegalArgumentException("Field and Value arrays must be of equal length.");
-        }
-
-        // keep this for posterity
-        _pClass = pClass;
-
-        // look up the cached primary key fields for this object
-        ColumnExp[] keyFields = DepotUtil.getKeyFields(pClass);
-
-        // fast path!
-        if (fields.length == 1 && keyFields.length == 1 && keyFields[0].equals(fields[0])) {
-            _values = new Comparable<?>[] { values[0] };
-
-        } else {
-            // build a local map of field name -> field value
-            Map<ColumnExp, Comparable<?>> map = Maps.newHashMap();
-            for (int ii = 0; ii < fields.length; ii++) {
-                map.put(fields[ii], values[ii]);
-            }
-
-            // now extract the values in field order and ensure none are extra or missing
-            _values = new Comparable<?>[values.length];
-            for (int ii = 0; ii < keyFields.length; ii++) {
-                Comparable<?> value = map.remove(keyFields[ii]);
-                if (value == null) {
-                    // make sure we were provided with a value for this primary key field
-                    throw new IllegalArgumentException(
-                        "Missing value for key field: " + keyFields[ii]);
-                }
-                if (!(value instanceof Serializable)) {
-                    throw new IllegalArgumentException(
-                        "Non-serializable argument [key=" + keyFields[ii] +
-                        ", value=" + value + "]");
-                }
-                _values[ii] = value;
-            }
-
-            // finally make sure we were not given any fields that are not primary key fields
-            if (map.size() > 0) {
-                throw new IllegalArgumentException(
-                    "Non-key columns given: " +  StringUtil.join(map.keySet().toArray(), ", "));
-            }
-        }
     }
 
     /**
@@ -284,6 +241,53 @@ public class Key<T extends PersistentRecord> extends WhereClause
         return builder.toString();
     }
 
+    protected static Comparable<?>[] toCanonicalOrder (
+        Class<? extends PersistentRecord> pClass, ColumnExp[] fields, Comparable<?>[] values)
+    {
+        if (fields.length != values.length) {
+            throw new IllegalArgumentException("Field and Value arrays must be of equal length.");
+        }
+
+        // look up the cached primary key fields for this object
+        ColumnExp[] keyFields = DepotUtil.getKeyFields(pClass);
+
+        // fast path!
+        if (fields.length == 1 && keyFields.length == 1 && keyFields[0].equals(fields[0])) {
+            return new Comparable<?>[] { values[0] };
+        }
+
+        // build a local map of field name -> field value
+        Map<ColumnExp, Comparable<?>> map = Maps.newHashMap();
+        for (int ii = 0; ii < fields.length; ii++) {
+            map.put(fields[ii], values[ii]);
+        }
+
+        // now extract the values in field order and ensure none are extra or missing
+        Comparable<?>[] cvalues = new Comparable<?>[values.length];
+        for (int ii = 0; ii < keyFields.length; ii++) {
+            Comparable<?> value = map.remove(keyFields[ii]);
+            if (value == null) {
+                // make sure we were provided with a value for this primary key field
+                throw new IllegalArgumentException(
+                    "Missing value for key field: " + keyFields[ii]);
+            }
+            if (!(value instanceof Serializable)) {
+                throw new IllegalArgumentException(
+                    "Non-serializable argument [key=" + keyFields[ii] +
+                    ", value=" + value + "]");
+            }
+            cvalues[ii] = value;
+        }
+
+        // finally make sure we were not given any fields that are not primary key fields
+        if (map.size() > 0) {
+            throw new IllegalArgumentException(
+                "Non-key columns given: " +  StringUtil.join(map.keySet().toArray(), ", "));
+        }
+
+        return cvalues;
+    }
+
     /** The persistent record type for which we are a key. */
     protected final Class<T> _pClass;