Remove setDataClass

src/main/java/com/maxmind/db/Networks.java

@@ -20,32 +20,39 @@ public class Networks<T> implements Iterator<DatabaseRecord<T>> {
     private NetworkNode lastNode;
     private final boolean skipAliasedNetworks;
     private final ByteBuffer buffer; /* Stores the buffer for Next() calls */
-    private Class<T> typeParameterClass;
+    private final Class<T> typeParameterClass;
 
     /**
      * Constructs a Networks instance.
      * @param reader The reader object.
      * @param skipAliasedNetworks The boolean to skip aliased networks.
+     * @param typeParameterClass The type of data returned by the iterator.
      * @throws ClosedDatabaseException Exception for a closed database.
      */
-    Networks(Reader reader, boolean skipAliasedNetworks) 
+    Networks(Reader reader, boolean skipAliasedNetworks, Class<T> typeParameterClass) 
         throws ClosedDatabaseException {
-        this(reader, skipAliasedNetworks, new NetworkNode[]{});
+        this(reader, skipAliasedNetworks, new NetworkNode[]{}, typeParameterClass);
     }
 
     /**
      * Constructs a Networks instance.
      * @param reader The reader object.
      * @param skipAliasedNetworks The boolean to skip aliased networks.
      * @param nodes The initial nodes array to start Networks iterator with.
+     * @param typeParameterClass The type of data returned by the iterator.
      * @throws ClosedDatabaseException Exception for a closed database.
      */
-    Networks(Reader reader, boolean skipAliasedNetworks, NetworkNode[] nodes) 
+    Networks(
+            Reader reader,
+            boolean skipAliasedNetworks,
+            NetworkNode[] nodes,
+            Class<T> typeParameterClass)
         throws ClosedDatabaseException {
         this.reader = reader;
         this.skipAliasedNetworks = skipAliasedNetworks;
         this.buffer = reader.getBufferHolder().get();
         this.nodes = new Stack<NetworkNode>();
+        this.typeParameterClass = typeParameterClass;
         for (NetworkNode node : nodes) {
             this.nodes.push(node);
         }
@@ -54,17 +61,10 @@ public class Networks<T> implements Iterator<DatabaseRecord<T>> {
     /**
      * Constructs a Networks instance with skipAliasedNetworks set to false by default.
      * @param reader The reader object.
+     * @param typeParameterClass The type of data returned by the iterator.
      */
-    Networks(Reader reader) throws ClosedDatabaseException {
-        this(reader, false);
-    }
-
-    /**
-     * Sets the Class for the data type in DataRecord.
-     * @param cls The class object. ( For example, Map.class )
-     */
-    public void setDataClass(Class<T> cls) {
-        this.typeParameterClass = cls;
+    Networks(Reader reader, Class<T> typeParameterClass) throws ClosedDatabaseException {
+        this(reader, false, typeParameterClass);
     }
 
     /**
@@ -101,7 +101,7 @@ public DatabaseRecord<T> next() {
 
             return new DatabaseRecord<T>(data, InetAddress.getByAddress(ip), prefixLength);
         } catch (IOException e) {
-            throw new NetworksIterationException(e.getMessage());
+            throw new NetworksIterationException(e);
         }
     }
 
@@ -156,7 +156,7 @@ public boolean hasNext()  {
                     this.nodes.push(new NetworkNode(ipRight, node.prefix, rightPointer));
                     node.pointer = this.reader.readNode(this.buffer, node.pointer, 0);
                 } catch (InvalidDatabaseException e) {
-                    throw new NetworksIterationException(e.getMessage());
+                    throw new NetworksIterationException(e);
                 }
             }
         }

src/main/java/com/maxmind/db/NetworksIterationException.java

@@ -1,7 +1,20 @@
 package com.maxmind.db;
 
+/**
+ * This class represents an error encountered while iterating over the networks.
+ * The most likely causes are corrupt data in the database, or a bug in the reader code.
+ * 
+ * This exception extends RuntimeException because it is thrown by the iterator
+ * methods in {@link Networks}.
+ * 
+ * @see Networks
+ */
 public class NetworksIterationException extends RuntimeException { 
     NetworksIterationException(String message) {
         super(message);
     }
+
+    NetworksIterationException(Throwable cause) {
+        super(cause);
+    }
 }

src/main/java/com/maxmind/db/Reader.java

@@ -205,14 +205,16 @@ record = this.readNode(buffer, record, bit);
      * separately. To disable skipAliasedNetworks, which iterates over the IPv4 networks 
      * only once, use the SkipAliasedNetworks parameter.
      * 
+     * @param <T> Represents the data type(e.g., Map, HastMap, etc.).
+     * @param typeParameterClass The type of data returned by the iterator.
      * @return Networks The Networks iterator.
      * @throws InvalidNetworkException Exception for using an IPv6 network in ipv4-only database.
      * @throws ClosedDatabaseException Exception for a closed databased.
      * @throws InvalidDatabaseException Exception for an invalid database.
      */
-    public Networks networks() throws 
+    public <T> Networks<T> networks(Class<T> typeParameterClass) throws 
         InvalidNetworkException, ClosedDatabaseException, InvalidDatabaseException {
-        return this.networks(true);
+        return this.networks(true, typeParameterClass);
     }
 
     /**
@@ -222,13 +224,16 @@ public Networks networks() throws
      * separately. To set the iteration over the IPv4 networks once, use the
      * SkipAliasedNetworks option.
      * 
+     * @param <T> Represents the data type(e.g., Map, HastMap, etc.).
      * @param skipAliasedNetworks Enable or disable skipping aliased networks.
      * @return Networks The Networks iterator.
      * @throws InvalidNetworkException Exception for using an IPv6 network in ipv4-only database.
      * @throws ClosedDatabaseException Exception for a closed databased.
      * @throws InvalidDatabaseException Exception for an invalid database.
      */
-    public Networks networks(boolean skipAliasedNetworks) throws 
+    public <T> Networks<T> networks(
+            boolean skipAliasedNetworks,
+            Class<T> typeParameterClass) throws
         InvalidNetworkException, ClosedDatabaseException, InvalidDatabaseException {
         try {
             InetAddress ipv4 = InetAddress.getByAddress(new byte[4]);
@@ -237,9 +242,9 @@ public Networks networks(boolean skipAliasedNetworks) throws
             Network ipAllV6 = new Network(ipv6, 0); // Mask 128.
 
             if (this.getMetadata().getIpVersion() == 6) {
-                return this.networksWithin(ipAllV6, skipAliasedNetworks);
+                return this.networksWithin(ipAllV6, skipAliasedNetworks, typeParameterClass);
             }
-            return this.networksWithin(ipAllV4, skipAliasedNetworks);
+            return this.networksWithin(ipAllV4, skipAliasedNetworks, typeParameterClass);
         } catch (UnknownHostException e) {
             /* This is returned by getByAddress. This should never happen
             as the ipv4 and ipv6 are constants set by us. */
@@ -288,12 +293,16 @@ private int findIpV4StartNode(ByteBuffer buffer)
      * @param <T> Represents the data type(e.g., Map, HastMap, etc.).
      * @param network Specifies the network to be iterated.
      * @param skipAliasedNetworks Boolean for skipping aliased networks.
+     * @param typeParameterClass The type of data returned by the iterator.
      * @return Networks
      * @throws InvalidNetworkException Exception for using an IPv6 network in ipv4-only database.
      * @throws ClosedDatabaseException Exception for a closed databased.
      * @throws InvalidDatabaseException Exception for an invalid database.
      */
-    public <T> Networks<T> networksWithin(Network network, boolean skipAliasedNetworks) 
+    public <T> Networks<T> networksWithin(
+            Network network,
+            boolean skipAliasedNetworks,
+            Class<T> typeParameterClass)
         throws InvalidNetworkException, ClosedDatabaseException, InvalidDatabaseException {
         InetAddress networkAddress = network.getNetworkAddress();
         if (this.metadata.getIpVersion() == 4 && networkAddress instanceof Inet6Address) {
@@ -321,7 +330,8 @@ public <T> Networks<T> networksWithin(Network network, boolean skipAliasedNetwor
         int prefix = traverseResult[1];
 
         Networks<T> networks = new Networks<T>(this, skipAliasedNetworks,
-            new Networks.NetworkNode[]{ new Networks.NetworkNode(ipBytes, prefix, node) });
+            new Networks.NetworkNode[]{new Networks.NetworkNode(ipBytes, prefix, node)},
+                typeParameterClass);
 
         return networks;
     }

src/test/java/com/maxmind/db/ReaderTest.java

@@ -85,8 +85,7 @@ public void testNetworks() throws IOException, InvalidDatabaseException, Invalid
                 File file = getFile("MaxMind-DB-test-ipv" + ipVersion + "-" + recordSize + ".mmdb");
 
                 Reader reader = new Reader(file);
-                Networks networks = reader.networks(false);
-                networks.setDataClass(Map.class); // This is needed before running any next().
+                Networks networks = reader.networks(false, Map.class);
 
                 while(networks.hasNext()) {
                     DatabaseRecord<Map<String, String>> iteration = networks.next();
@@ -109,8 +108,7 @@ public void testNetworksWithInvalidSearchTree() throws IOException, InvalidNetwo
         File file = getFile("MaxMind-DB-test-broken-search-tree-24.mmdb");
         Reader reader = new Reader(file);
 
-        Networks networks = reader.networks(false);
-        networks.setDataClass(Map.class);
+        Networks networks = reader.networks(false, Map.class);
 
         Exception exception = assertThrows(RuntimeException.class, () -> {
             while(networks.hasNext()){
@@ -338,8 +336,7 @@ public void testNetworksWithin() throws IOException, InvalidNetworkException{
                 InetAddress address = InetAddress.getByName(test.network);
                 Network network = new Network(address, test.prefix);
 
-                Networks networks = reader.networksWithin(network, test.skipAliasedNetworks);
-                networks.setDataClass(Map.class);
+                Networks networks = reader.networksWithin(network, test.skipAliasedNetworks, Map.class);
 
                 ArrayList<String> innerIPs  = new ArrayList<String>();
                 while(networks.hasNext()){
@@ -376,8 +373,7 @@ public void testGeoIPNetworksWithin() throws IOException, InvalidNetworkExceptio
             InetAddress address = InetAddress.getByName(test.network);
             Network network = new Network(address, test.prefix);
 
-            Networks networks = reader.networksWithin(network, test.skipAliasedNetworks);
-            networks.setDataClass(Map.class);
+            Networks networks = reader.networksWithin(network, test.skipAliasedNetworks, Map.class);
 
             ArrayList<String> innerIPs = new ArrayList<String>();
             while(networks.hasNext()){