docs: JavaDoc (#196)

Added JavaDoc comments to multiple classes and methods across the SDK,
providing detailed descriptions of their functionality and usage. This
enhances the readability and maintainability of the code.

DSP-119

Author: pflynn-virtru

sdk/src/main/java/io/opentdf/platform/sdk/AesGcm.java

@@ -12,6 +12,11 @@
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
 
+/**
+ * The AesGcm class provides encryption and decryption methods using AES-GCM mode.
+ * It includes methods to encrypt and decrypt byte arrays using a specified
+ * symmetric key.
+ */
 public class AesGcm {
     public static final int GCM_NONCE_LENGTH = 12; // in bytes
     public static final int GCM_TAG_LENGTH = 16; // in bytes

sdk/src/main/java/io/opentdf/platform/sdk/AssertionConfig.java

@@ -3,6 +3,10 @@
 
 import java.util.Objects;
 
+/**
+ * Represents the configuration for assertions, encapsulating various types, scopes, states, keys,
+ * and statements involved in assertion handling.
+ */
 public class AssertionConfig {
 
     public enum Type {

sdk/src/main/java/io/opentdf/platform/sdk/AsymDecryption.java

@@ -9,6 +9,9 @@
 import java.security.spec.PKCS8EncodedKeySpec;
 import java.util.Base64;
 
+/**
+ * Class providing functionality for asymmetric decryption using an RSA private key.
+ */
 public class AsymDecryption {
     private final PrivateKey privateKey;
     private static final String PRIVATE_KEY_HEADER = "-----BEGIN PRIVATE KEY-----";

sdk/src/main/java/io/opentdf/platform/sdk/AsymEncryption.java

@@ -15,6 +15,10 @@
 import java.util.Base64;
 import java.util.Objects;
 
+/**
+ * AsymEncryption class provides methods for asymmetric encryption and
+ * handling public keys in PEM format.
+ */
 public class AsymEncryption {
     private final PublicKey publicKey;
     private static final String PUBLIC_KEY_HEADER = "-----BEGIN PUBLIC KEY-----";

sdk/src/main/java/io/opentdf/platform/sdk/AutoConfigureException.java

@@ -1,5 +1,8 @@
 package io.opentdf.platform.sdk;
 
+/**
+ * Exception thrown when automatic configuration fails.
+ */
 public class AutoConfigureException extends RuntimeException  {
     public AutoConfigureException(String message) {
         super(message);

sdk/src/main/java/io/opentdf/platform/sdk/Autoconfigure.java

@@ -35,7 +35,11 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
-// Attribute rule types: operators!
+/**
+ * The RuleType class defines a set of constants that represent various types of attribute rules.
+ * These constants are used to specify the nature and behavior of attribute rules in the context
+ * of key management and policy enforcement.
+ */
 class RuleType {
     public static final String HIERARCHY = "hierarchy";
     public static final String ALL_OF = "allOf";
@@ -44,6 +48,12 @@ class RuleType {
     public static final String EMPTY_TERM = "DEFAULT";
 }
 
+/**
+ * The Autoconfigure class provides methods for configuring and retrieving
+ * grants related to attribute values and KAS (Key Access Server) keys.
+ * This class includes functionality to create granter instances based on
+ * attributes either from a list of attribute values or from a service.
+ */
 public class Autoconfigure {
 
     public static Logger logger = LoggerFactory.getLogger(Autoconfigure.class);

sdk/src/main/java/io/opentdf/platform/sdk/Config.java

@@ -10,6 +10,10 @@
 import java.util.*;
 import java.util.function.Consumer;
 
+/**
+ * Configuration class for setting various configurations related to TDF.
+ * Contains nested classes and enums for specific configuration settings.
+ */
 public class Config {
 
     public static final int TDF3_KEY_SIZE = 2048;

sdk/src/main/java/io/opentdf/platform/sdk/CryptoUtils.java

@@ -5,6 +5,9 @@
 import java.security.*;
 import java.util.Base64;
 
+/**
+ * Utility class for cryptographic operations such as generating RSA key pairs and calculating HMAC.
+ */
 public class CryptoUtils {
     private static final int KEYPAIR_SIZE = 2048;
 

sdk/src/main/java/io/opentdf/platform/sdk/InvalidZipException.java

@@ -1,5 +1,10 @@
 package io.opentdf.platform.sdk;
 
+/**
+ * InvalidZipException is thrown to indicate that a ZIP file being read
+ * is invalid or corrupted in some way. This exception extends RuntimeException,
+ * allowing it to be thrown during the normal operation of the Java Virtual Machine.
+ */
 public class InvalidZipException extends RuntimeException {
     public InvalidZipException(String message) {
         super(message);

sdk/src/main/java/io/opentdf/platform/sdk/KASClient.java

@@ -30,6 +30,11 @@
 
 import static java.lang.String.format;
 
+/**
+ * A client implementation that communicates with a Key Access Service (KAS).
+ * This class provides methods to retrieve public keys, unwrap encrypted keys,
+ * and manage key caches.
+ */
 public class KASClient implements SDK.KAS {
 
     private final Function<String, ManagedChannel> channelFactory;