fix: replace boilerplate code and consolidate common classes

at_client/src/main/java/org/atsign/client/api/AtKeyNames.java

@@ -0,0 +1,57 @@
+package org.atsign.client.api;
+
+import org.atsign.common.AtSign;
+
+/**
+ * Constants and Utility methods for "well known" standard keys
+ */
+public class AtKeyNames {
+
+  /**
+   * Key name for an Atsign's public encryption key
+   */
+  public static final String PUBLIC_ENCRYPT = "publickey";
+
+  /**
+   * Key name used during activation of Atsign server with CRAM authentication
+   */
+  public static final String PRIVATE_AT_SECRET = "privatekey:at_secret";
+
+  /**
+   * Key name used to store a shared encryption key between two {@link AtSign}s
+   */
+  public static final String SHARED_KEY = "shared_key";
+
+  /**
+   * Key name used during enrollment completion, this is used to obtain the self encryption
+   * for an {@link AtSign}
+   */
+  public static final String SELF_ENCRYPTION_KEY = "default_self_enc_key";
+
+  /**
+   * Key name used during enrollment completion, this is used to obtain the private encryption
+   * key for an {@link AtSign}
+   */
+  public static final String ENCRYPT_PRIVATE_KEY = "default_enc_private_key";
+
+  /**
+   * Returns the key name used to store the shared encryption key encrypted with
+   * the sharedBy {@link AtSign}'s public key
+   *
+   * @param sharedWith the sharedWith (recipient) {@link AtSign}
+   * @return the fully qualified key name
+   */
+  public static String toSharedByMeKeyName(AtSign sharedWith) {
+    return String.format("%s.%s", SHARED_KEY, sharedWith.withoutPrefix());
+  }
+
+
+  /**
+   *
+   * @return the key used to shared
+   */
+  public static String toSharedWithMeKeyName(AtSign sharedBy, AtSign sharedWith) {
+    return String.format("%s:%s%s", SHARED_KEY, sharedWith, sharedBy);
+  }
+
+}

at_client/src/main/java/org/atsign/client/api/AtKeys.java

@@ -1,196 +1,151 @@
 package org.atsign.client.api;
 
+import java.security.Key;
 import java.security.KeyPair;
-import java.security.PrivateKey;
-import java.security.PublicKey;
 import java.util.Base64;
 import java.util.Collections;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
 import org.atsign.client.util.EnrollmentId;
 
+import lombok.Builder;
+import lombok.Value;
+
 /**
- * Data class used to hold an {@link org.atsign.client.api.AtClient}s keys
+ * An immutable class used to hold an {@link org.atsign.client.api.AtClient}s keys.
+ * <p>
+ * Examples:
+ *
+ * <pre>
+ * AtKeys keys = AtKeys.builder()
+ *     .selfEncryptKey(generateAESKeyBase64())
+ *     .apkamKeyPair(generateRSAKeyPair())
+ *     .apkamSymmetricKey(generateAESKeyBase64())
+ *     .build();
+ *
+ * keys = keys.toBuilder().enrollmentId(enrollmentId).build();
+ * </pre>
  */
+@Value
+@Builder(toBuilder = true)
 public class AtKeys {
 
   /**
    * unique id which is assigned by the at_server at enrollment time, this is associated with a
-   * specific
-   * application and device and therefore a specific the apkam key pair
+   * specific application and device and therefore a specific the apkam key pair
    */
-  private EnrollmentId enrollmentId;
+  EnrollmentId enrollmentId;
 
   /**
    * Public Key used for Authentication Management, once this is stored in the at_server then an
    * {@link org.atsign.client.api.AtClient} is able to authenticate using the corresponding private
    * key.
    */
-  private String apkamPublicKey;
+  String apkamPublicKey;
 
   /**
    * Private Key used for Authentication Management, this is used to sign the challenge during
    * authentication with the at_server.
    */
-  private String apkamPrivateKey;
+  String apkamPrivateKey;
 
   /**
    * Encryption Key used during enrollment. This key is sent as part of the enrollment request
-   * (encrypted
-   * with the atsigns public encryption key). The process that approves the enrollment request uses
-   * this
-   * key to encrypt the {@link #selfEncryptKey} and {@link #encryptPrivateKey} in the response that it
-   * sends.
+   * (encrypted with the atsigns public encryption key). The process that approves the enrollment
+   * request uses this key to encrypt the {@link #selfEncryptKey} and {@link #encryptPrivateKey}
+   * in the response that it sends.
    * The process which requested the enrollment can then decrypt and store those keys.
    * This ensures that all {@link AtKeys} got and {@link org.atsign.common.AtSign} share the same
    * {@link #selfEncryptKey} and {@link #encryptPrivateKey}
    */
-  private String apkamSymmetricKey;
+  String apkamSymmetricKey;
 
   /**
    * Encryption Key used to encrypt {@link org.atsign.common.Keys.SelfKey}s and the pkam and
    * encryption key pairs
    * when they are externalised as JSON
    */
-  private String selfEncryptKey;
+  String selfEncryptKey;
 
   /**
    * This is used to encrypt the symmetric keys that are used to encrypt
    * {@link org.atsign.common.Keys.SharedKey}s
    * where the shared with {@link org.atsign.common.AtSign} is this {@link org.atsign.common.AtSign}
    */
 
-  private String encryptPublicKey;
+  String encryptPublicKey;
 
   /**
    * This is used to decrypt the symmetric keys that are used to encrypt
    * {@link org.atsign.common.Keys.SharedKey}s
    * where the shared with {@link org.atsign.common.AtSign} is this {@link org.atsign.common.AtSign}
    */
-  private String encryptPrivateKey;
+  String encryptPrivateKey;
 
   /**
    * Transient cache of other keys
    */
-  private Map<String, String> cache = new ConcurrentHashMap<>();
+  Map<String, String> cache = new ConcurrentHashMap<>();
 
+  /**
+   * @return true if these {link @AtKeys} have enrollment id
+   */
   public boolean hasEnrollmentId() {
     return enrollmentId != null;
   }
 
-  public EnrollmentId getEnrollmentId() {
-    return enrollmentId;
-  }
-
-  public AtKeys setEnrollmentId(EnrollmentId enrollmentId) {
-    this.enrollmentId = enrollmentId;
-    return this;
-  }
-
-  public String getSelfEncryptKey() {
-    return selfEncryptKey;
-  }
-
-  public AtKeys setSelfEncryptKey(String key) {
-    this.selfEncryptKey = key;
-    return this;
-  }
-
-  public String getApkamPublicKey() {
-    return apkamPublicKey;
-  }
-
-  public AtKeys setApkamPublicKey(String key) {
-    this.apkamPublicKey = key;
-    return this;
-  }
-
-  public AtKeys setApkamPublicKey(PublicKey key) {
-    return setApkamPublicKey(createStringBase64(key));
-  }
-
-  public String getApkamPrivateKey() {
-    return apkamPrivateKey;
-  }
-
-  public AtKeys setApkamPrivateKey(String key) {
-    this.apkamPrivateKey = key;
-    return this;
-  }
-
-  public AtKeys setApkamPrivateKey(PrivateKey key) {
-    return setApkamPrivateKey(createStringBase64(key));
-  }
-
-  public AtKeys setApkamKeyPair(KeyPair keyPair) {
-    setApkamPublicKey(keyPair.getPublic());
-    setApkamPrivateKey(keyPair.getPrivate());
-    return this;
-  }
-
-  public boolean hasPkamKeys() {
-    return this.apkamPublicKey != null && this.apkamPrivateKey != null;
-  }
-
-  public AtKeys setEncryptKeyPair(KeyPair keyPair) {
-    setEncryptPublicKey(keyPair.getPublic());
-    setEncryptPrivateKey(keyPair.getPrivate());
-    return this;
-  }
-
-  public String getEncryptPublicKey() {
-    return encryptPublicKey;
-  }
-
-  public AtKeys setEncryptPublicKey(String key) {
-    this.encryptPublicKey = key;
-    return this;
-  }
-
-  public AtKeys setEncryptPublicKey(PublicKey key) {
-    return setEncryptPublicKey(createStringBase64(key));
-  }
-
-  public String getEncryptPrivateKey() {
-    return encryptPrivateKey;
-  }
-
-  public AtKeys setEncryptPrivateKey(String key) {
-    this.encryptPrivateKey = key;
-    return this;
-  }
-
-  public AtKeys setEncryptPrivateKey(PrivateKey key) {
-    return setEncryptPrivateKey(createStringBase64(key));
-  }
-
-  public String getApkamSymmetricKey() {
-    return apkamSymmetricKey;
-  }
-
-  public AtKeys setApkamSymmetricKey(String key) {
-    this.apkamSymmetricKey = key;
-    return this;
+  /**
+   * @return true if these {link @AtKeys} have APKAM private key set
+   */
+  public boolean hasPkamKey() {
+    return this.apkamPrivateKey != null;
   }
 
+  /**
+   * Allows the retrieval of previously put key values from the transient cache.
+   *
+   * @param key for the cached value
+   * @return cached value or null if no entry
+   */
   public String get(String key) {
     return cache.get(key);
   }
 
+  /**
+   * Allows the storage key values in the transient cache.
+   *
+   * @param key for the cached value
+   * @param value the cached value
+   */
   public void put(String key, String value) {
     cache.put(key, value);
   }
 
+  /**
+   * @return an immutable map of all the transient cached values
+   */
   public Map<String, String> getCache() {
     return Collections.unmodifiableMap(cache);
   }
 
-  private static String createStringBase64(PublicKey key) {
-    return Base64.getEncoder().encodeToString(key.getEncoded());
+  /**
+   * Builder utility.
+   */
+  public static class AtKeysBuilder {
+
+    public AtKeysBuilder encryptKeyPair(KeyPair keyPair) {
+      return this.encryptPublicKey(createStringBase64(keyPair.getPublic()))
+          .encryptPrivateKey(createStringBase64(keyPair.getPrivate()));
+    }
+
+    public AtKeysBuilder apkamKeyPair(KeyPair keyPair) {
+      return this.apkamPublicKey(createStringBase64(keyPair.getPublic()))
+          .apkamPrivateKey(createStringBase64(keyPair.getPrivate()));
+    }
   }
 
-  private static String createStringBase64(PrivateKey key) {
+  private static String createStringBase64(Key key) {
     return Base64.getEncoder().encodeToString(key.getEncoded());
   }