claim class with claim converter

Author: BastiaanJansen

src/main/java/com/bastiaanjansen/jwt/ClaimConverter.java

@@ -0,0 +1,6 @@
+package com.bastiaanjansen.jwt;
+
+@FunctionalInterface
+public interface ClaimConverter<T> {
+    T convert(Object value);
+}

src/main/java/com/bastiaanjansen/jwt/Claims.java

@@ -0,0 +1,47 @@
+package com.bastiaanjansen.jwt;
+
+import com.bastiaanjansen.jwt.Utils.Base64Utils;
+import org.json.JSONObject;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Claims {
+    protected final Map<String, Object> claims;
+
+    protected Claims() {
+        claims = new HashMap<>();
+    }
+
+    public boolean containsClaim(String name) {
+        return claims.containsKey(name);
+    }
+
+    public Map<String, Object> getAsMap() {
+        return new HashMap<>(claims);
+    }
+
+    public String base64Encoded() {
+        return Base64Utils.encodeBase64URL(new JSONObject(claims).toString());
+    }
+
+    public Object getClaim(String name) {
+        return claims.get(name);
+    }
+
+    public <T> T getClaim(String name, Class<T> type) {
+        Object value = claims.get(name);
+        return type.cast(value);
+    }
+
+    public <T> T getClaim(String name, ClaimConverter<T> converter) {
+        Object value = claims.get(name);
+        return converter.convert(value);
+    }
+
+    public void addClaim(String name, Object value) {
+        if (name == null) throw new IllegalArgumentException("name cannot be null");
+        if (value == null) throw new IllegalArgumentException("value cannot be null");
+        claims.put(name, value);
+    }
+}

src/main/java/com/bastiaanjansen/jwt/Header.java

@@ -3,20 +3,16 @@
 import com.bastiaanjansen.jwt.Utils.Base64Utils;
 import org.json.JSONObject;
 
-import java.util.HashMap;
 import java.util.Map;
 
-public class Header {
+public class Header extends Claims {
     public static class Registered {
         static String TYPE = "typ";
         static String CONTENT_TYPE = "cty";
         static String ALGORITHM = "alg";
     }
 
-    private final Map<String, Object> claims;
-
     public Header() {
-        claims = new HashMap<>();
         setType("JWT");
     }
 
@@ -36,52 +32,22 @@ public void setType(String type) {
     }
 
     public String getType() {
-        Object type = claims.get(Registered.TYPE);
-        return getString(type);
+        return getClaim(Registered.TYPE, String.class);
     }
 
     public void setContentType(String value) {
         addClaim(Registered.CONTENT_TYPE, value);
     }
 
     public String getContentType() {
-        Object contentType = claims.get(Registered.CONTENT_TYPE);
-        return getString(contentType);
+        return getClaim(Registered.CONTENT_TYPE, String.class);
     }
 
     public void setAlgorithm(String algorithm) {
         addClaim(Registered.ALGORITHM, algorithm);
     }
 
     public String getAlgorithm() {
-        Object algorithm = claims.get(Registered.ALGORITHM);
-        return getString(algorithm);
-    }
-
-    public boolean containsClaim(String name) {
-        return claims.containsKey(name);
-    }
-
-    public Map<String, Object> getAsMap() {
-        return new HashMap<>(claims);
-    }
-
-    public String base64Encoded() {
-        return Base64Utils.encodeBase64URL(new JSONObject(claims).toString());
-    }
-
-    public Object getClaim(String name) {
-        return claims.get(name);
-    }
-
-    public void addClaim(String name, Object value) {
-        if (name == null) throw new IllegalArgumentException("name cannot be null");
-        if (value == null) throw new IllegalArgumentException("value cannot be null");
-
-        claims.put(name, value);
-    }
-
-    private String getString(Object object) {
-        return object != null ? String.valueOf(object) : null;
+        return getClaim(Registered.ALGORITHM, String.class);
     }
 }

src/main/java/com/bastiaanjansen/jwt/Payload.java

@@ -7,7 +7,7 @@
 import java.util.HashMap;
 import java.util.Map;
 
-public class Payload {
+public class Payload extends Claims {
     public static class Registered {
         static String ISSUER = "iss";
         static String SUBJECT = "sub";
@@ -18,14 +18,10 @@ public static class Registered {
         static String JWT_ID = "jti";
     }
 
-    private final Map<String, Object> claims;
-
-    public Payload() {
-        claims = new HashMap<>();
-    }
+    public Payload() {}
 
     public Payload(Map<String, Object> map) {
-        claims = new HashMap<>(map);
+        claims.putAll(map);
     }
 
     public static Payload fromBase64EncodedJSON(String encodedJSON) {
@@ -39,17 +35,15 @@ public void setIssuer(String issuer) {
     }
 
     public String getIssuer() {
-        Object issuer = claims.get(Registered.ISSUER);
-        return getString(issuer);
+        return getClaim(Registered.ISSUER, String.class);
     }
 
     public void setSubject(String subject) {
         addClaim(Registered.SUBJECT, subject);
     }
 
     public String getSubject() {
-        Object subject = claims.get(Registered.SUBJECT);
-        return getString(subject);
+        return getClaim(Registered.SUBJECT, String.class);
     }
 
     public void setAudience(String... audience) {
@@ -109,34 +103,7 @@ public void setID(String id) {
     }
 
     public String getID() {
-        Object id = claims.get(Registered.JWT_ID);
-        return getString(id);
-    }
-
-    public boolean containsClaim(String name) {
-        return claims.containsKey(name);
-    }
-
-    public void addClaim(String name, Object value) {
-        if (name == null) throw new IllegalArgumentException("name cannot be null");
-        if (value == null) throw new IllegalArgumentException("value cannot be null");
-        claims.put(name, value);
-    }
-
-    public Object getClaim(String name) {
-        return claims.get(name);
-    }
-
-    public Map<String, Object> getAsMap() {
-        return new HashMap<>(claims);
-    }
-
-    public String base64Encoded() {
-        return Base64Utils.encodeBase64URL(new JSONObject(claims).toString());
-    }
-
-    private String getString(Object object) {
-        return object != null ? String.valueOf(object) : null;
+        return getClaim(Registered.JWT_ID, String.class);
     }
 
     private Date getDate(Object object) {

src/test/java/com/bastiaanjansen/jwt/JWTTest.java

@@ -130,7 +130,7 @@ void builder_withClaim() throws JWTCreationException {
         JWT jwt = new JWT.Builder(algorithm).withClaim("custom-claim", "custom-claim-value").build();
         String expected = "custom-claim-value";
 
-        assertThat(jwt.getPayload().getClaim("custom-claim"), is(expected));
+        assertThat(jwt.getPayload().getClaim("custom-claim", String.class), is(expected));
     }
 
     @Test