Add OpenPgpFingerprint.parse(String)

pgpainless-core/src/main/java/org/pgpainless/key/OpenPgpFingerprint.java

@@ -50,6 +50,23 @@ public abstract class OpenPgpFingerprint implements CharSequence, Comparable<Ope
         return of(ring.getPublicKey());
     }
 
+    /**
+     * Try to parse an {@link OpenPgpFingerprint} from the given fingerprint string.
+     *
+     * @param fingerprint fingerprint
+     * @return parsed fingerprint
+     */
+    public static OpenPgpFingerprint parse(String fingerprint) {
+        String fp = fingerprint.replace(" ", "").trim().toUpperCase();
+        if (fp.matches("^[0-9A-F]{40}$")) {
+            return new OpenPgpV4Fingerprint(fp);
+        }
+        if (fp.matches("^[0-9A-F]{64}$")) {
+            return new OpenPgpV5Fingerprint(fp);
+        }
+        throw new IllegalArgumentException("Fingerprint does not appear to match any known fingerprint patterns.");
+    }
+
     public OpenPgpFingerprint(String fingerprint) {
         String fp = fingerprint.replace(" ", "").trim().toUpperCase();
         if (!isValid(fp)) {

pgpainless-core/src/test/java/org/pgpainless/key/OpenPgpV4FingerprintTest.java

@@ -7,6 +7,7 @@ package org.pgpainless.key;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.IOException;
 import java.net.URI;
@@ -91,4 +92,14 @@ public class OpenPgpV4FingerprintTest {
         OpenPgpV4Fingerprint fingerprint = new OpenPgpV4Fingerprint(prettyPrint);
         assertEquals(prettyPrint, fingerprint.prettyPrint());
     }
+
+    @Test
+    public void testParse() {
+        String prettyPrint = "C94B 884B 9A56 7B1C FB23  6999 7DC5 BDAC BBDF BF87";
+        OpenPgpFingerprint parsed = OpenPgpFingerprint.parse(prettyPrint);
+
+        assertTrue(parsed instanceof OpenPgpV4Fingerprint);
+        OpenPgpV4Fingerprint v4fp = (OpenPgpV4Fingerprint) parsed;
+        assertEquals(prettyPrint, v4fp.prettyPrint());
+    }
 }

pgpainless-core/src/test/java/org/pgpainless/key/OpenPgpV5FingerprintTest.java

@@ -7,6 +7,7 @@ package org.pgpainless.key;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class OpenPgpV5FingerprintTest {
 
@@ -22,4 +23,14 @@ public class OpenPgpV5FingerprintTest {
         long id = fingerprint.getKeyId();
         assertEquals("76543210abcdefab", Long.toHexString(id));
     }
+
+    @Test
+    public void testParse() {
+        String prettyPrint = "76543210 ABCDEFAB 01AB23CD 1C0FFEE1  1EEFF0C1 DC32BA10 BAFEDCBA 01234567";
+        OpenPgpFingerprint parsed = OpenPgpFingerprint.parse(prettyPrint);
+
+        assertTrue(parsed instanceof OpenPgpV5Fingerprint);
+        OpenPgpV5Fingerprint v5fp = (OpenPgpV5Fingerprint) parsed;
+        assertEquals(prettyPrint, v5fp.prettyPrint());
+    }
 }