Add docs for types

Author: shadromani

checkstyle.xml

@@ -333,20 +333,13 @@
             <property name="allowedAnnotations" value="Override, Test"/>
             <property name="tokens" value="METHOD_DEF, CTOR_DEF, ANNOTATION_FIELD_DEF, COMPACT_CTOR_DEF"/>
         </module>
-        <!-- <module name="MissingJavadocMethod">
-            <property name="scope" value="public"/>
-            <property name="minLineCount" value="2"/>
-            <property name="allowedAnnotations" value="Override, Test"/>
-            <property name="tokens" value="METHOD_DEF, CTOR_DEF, ANNOTATION_FIELD_DEF,
-                                   COMPACT_CTOR_DEF"/>
-        </module>
         <module name="MissingJavadocType">
             <property name="scope" value="protected"/>
             <property name="tokens"
                       value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF,
                       RECORD_DEF, ANNOTATION_DEF"/>
             <property name="excludeScope" value="nothing"/>
-        </module> -->
+        </module>
         <module name="MethodName">
             <property name="format" value="^[a-z][a-z0-9]\w*$"/>
             <message key="name.invalidPattern"

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

@@ -1,5 +1,10 @@
 package com.maxmind.db;
 
+/**
+ * CacheKey is used as a key in the node cache. It contains the offset of the
+ * node in the database file, the class of the data at that node, and the type
+ * of the data at that node.
+ */
 public final class CacheKey<T> {
     private final int offset;
     private final Class<T> cls;

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

@@ -1,5 +1,9 @@
 package com.maxmind.db;
 
+/**
+ * DecodedValue is a wrapper for the decoded value and the number of bytes used
+ * to decode it.
+ */
 public final class DecodedValue {
     final Object value;
 

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

@@ -2,6 +2,10 @@
 
 import java.net.InetAddress;
 
+/**
+ * This is a custom exception that is thrown when the user attempts to use an
+ * IPv6 address in an IPv4-only database.
+ */
 public class InvalidNetworkException extends Exception {
     public InvalidNetworkException(InetAddress ip) {
         super("you attempted to use an IPv6 network in an IPv4-only database: " + ip.toString());

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

@@ -3,6 +3,11 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 
+/**
+ * MaxMindDbConstructor is an annotation that can be used to mark a constructor
+ * that should be used to create an instance of a class when decoding a MaxMind
+ * DB file.
+ */
 @Retention(RetentionPolicy.RUNTIME)
 public @interface MaxMindDbConstructor {
 }

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

@@ -3,6 +3,11 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 
+/**
+ * Interface for a MaxMind DB parameter. This is used to mark a parameter that
+ * should be used to create an instance of a class when decoding a MaxMind DB
+ * file.
+ */
 @Retention(RetentionPolicy.RUNTIME)
 public @interface MaxMindDbParameter {
     String name();

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

@@ -5,6 +5,9 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Metadata holds data associated with the database itself.
+ */
 public final class Metadata {
     private final int binaryFormatMajorVersion;
     private final int binaryFormatMinorVersion;

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

@@ -2,8 +2,13 @@
 
 import java.io.IOException;
 
+/**
+ * NodeCache is an interface for a cache that stores decoded nodes.
+ */
 public interface NodeCache {
-
+    /**
+     * A loader is used to load a value for a key that is not in the cache.
+     */
     interface Loader {
         DecodedValue load(CacheKey key) throws IOException;
     }