109: enabled injection of a time source - a 'Clock'

src/main/java/io/jsonwebtoken/Clock.java

@@ -1,7 +1,22 @@
 package io.jsonwebtoken;
 
+import io.jsonwebtoken.impl.DefaultClock;
+
 import java.util.Date;
 
+/**
+ * A clock represents a time source that can be used when creating and verifying JWTs.
+ *
+ * @since 0.7.0
+ */
 public interface Clock {
+
+    public static final Clock DEFAULT = new DefaultClock();
+
+    /**
+     * Returns the clock's current timestamp at the instant the method is invoked.
+     *
+     * @return the clock's current timestamp at the instant the method is invoked.
+     */
     Date now();
 }

src/main/java/io/jsonwebtoken/DefaultClock.java

@@ -1,10 +0,0 @@
-package io.jsonwebtoken;
-
-import java.util.Date;
-
-public class DefaultClock implements Clock {
-    @Override
-    public Date now() {
-        return new Date();
-    }
-}

src/main/java/io/jsonwebtoken/JwtParser.java

@@ -15,6 +15,8 @@
  */
 package io.jsonwebtoken;
 
+import io.jsonwebtoken.impl.DefaultClock;
+
 import java.security.Key;
 import java.util.Date;
 
@@ -125,11 +127,12 @@ public interface JwtParser {
     JwtParser require(String claimName, Object value);
 
     /**
-     * Replace the {@code clock} used by the parser to determine the current time-of-day to use when validating
-     * the parsed JWT. If {@code null}, will reset the behavior to use the system clock.
+     * Sets the {@link Clock} that determines the timestamp to use when validating the parsed JWT.
+     * The parser uses a {@link DefaultClock DefaultClock} instance by default.
      *
-     * @param clock a {@code Clock} object to return the time-of-day or {@code null}
+     * @param clock a {@code Clock} object to return the timestamp to use when validating the parsed JWT.
      * @return the builder instance for method chaining.
+     * @since 0.7.0
      */
     JwtParser setClock(Clock clock);
 

src/main/java/io/jsonwebtoken/impl/DefaultClock.java

@@ -0,0 +1,23 @@
+package io.jsonwebtoken.impl;
+
+import io.jsonwebtoken.Clock;
+
+import java.util.Date;
+
+/**
+ * Default {@link Clock} implementation.
+ *
+ * @since 0.7.0
+ */
+public class DefaultClock implements Clock {
+
+    /**
+     * Simply returns <code>new {@link Date}()</code>.
+     *
+     * @return a new {@link Date} instance.
+     */
+    @Override
+    public Date now() {
+        return new Date();
+    }
+}

src/main/java/io/jsonwebtoken/impl/DefaultJwtParser.java

@@ -21,7 +21,6 @@ import io.jsonwebtoken.Claims;
 import io.jsonwebtoken.Clock;
 import io.jsonwebtoken.CompressionCodec;
 import io.jsonwebtoken.CompressionCodecResolver;
-import io.jsonwebtoken.DefaultClock;
 import io.jsonwebtoken.ExpiredJwtException;
 import io.jsonwebtoken.Header;
 import io.jsonwebtoken.IncorrectClaimException;
@@ -71,7 +70,7 @@ public class DefaultJwtParser implements JwtParser {
 
     Claims expectedClaims = new DefaultClaims();
 
-    private Clock clock = new DefaultClock();
+    private Clock clock = Clock.DEFAULT;
 
     @Override
     public JwtParser requireIssuedAt(Date issuedAt) {
@@ -133,12 +132,8 @@ public class DefaultJwtParser implements JwtParser {
 
     @Override
     public JwtParser setClock(Clock clock) {
-        if (clock == null) {
-            this.clock = new DefaultClock();
-        } else {
+        Assert.notNull(clock, "Clock instance cannot be null.");
         this.clock = clock;
-        }
-
         return this;
     }
 

src/main/java/io/jsonwebtoken/impl/FixedClock.java

@@ -4,13 +4,30 @@ import io.jsonwebtoken.Clock;
 
 import java.util.Date;
 
+/**
+ * A {@code Clock} implementation that is constructed with a seed timestamp and always reports that same
+ * timestamp.
+ *
+ * @since 0.7.0
+ */
 public class FixedClock implements Clock {
+
     private final Date now;
 
+    /**
+     * Creates a new fixed clock using <code>new {@link Date Date}()</code> as the seed timestamp.  All calls to
+     * {@link #now now()} will always return this seed Date.
+     */
     public FixedClock() {
         this(new Date());
     }
 
+    /**
+     * Creates a new fixed clock using the specified seed timestamp.  All calls to
+     * {@link #now now()} will always return this seed Date.
+     *
+     * @param now the specified Date to always return from all calls to {@link #now now()}.
+     */
     public FixedClock(Date now) {
         this.now = now;
     }

src/test/groovy/io/jsonwebtoken/JwtParserTest.groovy

@@ -15,6 +15,7 @@
  */
 package io.jsonwebtoken
 
+import io.jsonwebtoken.impl.DefaultClock
 import io.jsonwebtoken.impl.FixedClock
 import io.jsonwebtoken.impl.TextCodec
 import org.junit.Test
@@ -1407,15 +1408,11 @@ class JwtParserTest {
 
     @Test
     void testParseClockManipulationWithNullClock() {
-        Date expiry = new Date(System.currentTimeMillis() - 1000)
-
-        String compact = Jwts.builder().setSubject('Joe').setExpiration(expiry).compact()
-
+        JwtParser parser = Jwts.parser();
         try {
-            Jwts.parser().setClock(null).parse(compact)
+            parser.setClock(null)
             fail()
-        } catch (ExpiredJwtException e) {
-            assertTrue e.getMessage().startsWith('JWT expired at ')
+        } catch (IllegalArgumentException expected) {
         }
     }
 

src/test/groovy/io/jsonwebtoken/impl/FixedClockTest.groovy

@@ -0,0 +1,19 @@
+package io.jsonwebtoken.impl
+
+import org.junit.Test
+import static org.junit.Assert.*
+
+class FixedClockTest {
+
+    @Test
+    void testFixedClockDefaultConstructor() {
+
+        def clock = new FixedClock()
+
+        def date1 = clock.now()
+        Thread.sleep(100)
+        def date2 = clock.now()
+
+        assertSame date1, date2
+    }
+}