added bindChallenge

acme4j-client/src/main/java/org/shredzone/acme4j/Login.java

@@ -123,6 +123,18 @@ public class Login {
         return new Order(this, requireNonNull(location, "location"));
     }
 
+    /**
+     * Creates a new instance of {@link Challenge} and binds it to this login.
+     *
+     * @param location
+     *            Location URL of the challenge
+     * @return
+     *            {@link Challenge} bound to the login
+     */
+    public Challenge bindChallenge(URL location) {
+        return new Challenge(this, requireNonNull(location, "location"));
+    }
+
     /**
      * Creates a {@link Challenge} instance for the given challenge data.
      *

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/Challenge.java

@@ -13,6 +13,7 @@
  */
 package org.shredzone.acme4j.challenge;
 
+import java.net.URL;
 import java.time.Instant;
 
 import javax.annotation.CheckForNull;
@@ -51,6 +52,11 @@ public class Challenge extends AcmeJsonResource {
     protected static final String KEY_VALIDATED = "validated";
     protected static final String KEY_ERROR = "error";
 
+    public Challenge(Login login, URL location) {
+        super(login, location);
+    }
+
+
     /**
      * Creates a new generic {@link Challenge} object.
      *

acme4j-client/src/test/java/org/shredzone/acme4j/LoginTest.java

@@ -83,6 +83,11 @@ public class LoginTest {
         assertThat(order, is(notNullValue()));
         assertThat(order.getLogin(), is(login));
         assertThat(order.getLocation(), is(resourceUrl));
+
+        Challenge challenge = login.bindChallenge(resourceUrl);
+        assertThat(challenge, is(notNullValue()));
+        assertThat(challenge.getLogin(), is(login));
+        assertThat(challenge.getLocation(), is(resourceUrl));
     }
 
     /**