Reduce scope of Service Loader work to CompressionCodecs and JsonSeri…

…alizers

Fixes: #458

api/src/main/java/io/jsonwebtoken/CompressionCodecs.java

@@ -15,7 +15,7 @@
  */
 package io.jsonwebtoken;
 
-import io.jsonwebtoken.lang.Services;
+import io.jsonwebtoken.lang.Classes;
 
 /**
  * Provides default implementations of the {@link CompressionCodec} interface.
@@ -26,16 +26,15 @@
  */
 public final class CompressionCodecs {
 
-    private static final CompressionCodecFactory FACTORY = Services.loadFirst(CompressionCodecFactory.class);
-
     private CompressionCodecs() {
     } //prevent external instantiation
 
     /**
      * Codec implementing the <a href="https://tools.ietf.org/html/rfc7518">JWA</a> standard
      * <a href="https://en.wikipedia.org/wiki/DEFLATE">deflate</a> compression algorithm
      */
-    public static final CompressionCodec DEFLATE = FACTORY.deflateCodec();
+    public static final CompressionCodec DEFLATE =
+        Classes.newInstance("io.jsonwebtoken.impl.compression.DeflateCompressionCodec");
 
     /**
      * Codec implementing the <a href="https://en.wikipedia.org/wiki/Gzip">gzip</a> compression algorithm.
@@ -44,6 +43,7 @@ private CompressionCodecs() {
      * that all parties accessing the token support the gzip algorithm.</p>
      * <p>If you're concerned about compatibility, the {@link #DEFLATE DEFLATE} code is JWA standards-compliant.</p>
      */
-    public static final CompressionCodec GZIP = FACTORY.gzipCodec();
+    public static final CompressionCodec GZIP =
+        Classes.newInstance("io.jsonwebtoken.impl.compression.GzipCompressionCodec");
 
 }

api/src/main/java/io/jsonwebtoken/Jwts.java

@@ -15,19 +15,19 @@
  */
 package io.jsonwebtoken;
 
-import io.jsonwebtoken.lang.Services;
+import io.jsonwebtoken.lang.Classes;
 
 import java.util.Map;
 
 /**
  * Factory class useful for creating instances of JWT interfaces.  Using this factory class can be a good
  * alternative to tightly coupling your code to implementation classes.
  *
- * @since 0.11
+ * @since 0.1
  */
 public final class Jwts {
 
-    private static final JwtFactory FACTORY = Services.loadFirst(JwtFactory.class);
+    private static final Class[] MAP_ARG = new Class[]{Map.class};
 
     private Jwts() {
     }
@@ -40,7 +40,7 @@ private Jwts() {
      * @return a new {@link Header} instance suitable for <em>plaintext</em> (not digitally signed) JWTs.
      */
     public static Header header() {
-        return FACTORY.header();
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultHeader");
     }
 
     /**
@@ -51,7 +51,7 @@ public static Header header() {
      * @return a new {@link Header} instance suitable for <em>plaintext</em> (not digitally signed) JWTs.
      */
     public static Header header(Map<String, Object> header) {
-        return FACTORY.header(header);
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultHeader", MAP_ARG, header);
     }
 
     /**
@@ -61,7 +61,7 @@ public static Header header(Map<String, Object> header) {
      * @see JwtBuilder#setHeader(Header)
      */
     public static JwsHeader jwsHeader() {
-        return FACTORY.jwsHeader();
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultJwsHeader");
     }
 
     /**
@@ -73,7 +73,7 @@ public static JwsHeader jwsHeader() {
      * @see JwtBuilder#setHeader(Header)
      */
     public static JwsHeader jwsHeader(Map<String, Object> header) {
-        return FACTORY.jwsHeader(header);
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultJwsHeader", MAP_ARG, header);
     }
 
     /**
@@ -82,7 +82,7 @@ public static JwsHeader jwsHeader(Map<String, Object> header) {
      * @return a new {@link Claims} instance to be used as a JWT body.
      */
     public static Claims claims() {
-        return FACTORY.claims();
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultClaims");
     }
 
     /**
@@ -92,7 +92,7 @@ public static Claims claims() {
      * @return a new {@link Claims} instance populated with the specified name/value pairs.
      */
     public static Claims claims(Map<String, Object> claims) {
-        return FACTORY.claims(claims);
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultClaims", MAP_ARG, claims);
     }
 
     /**
@@ -118,7 +118,7 @@ public static Claims claims(Map<String, Object> claims) {
      */
     @Deprecated
     public static JwtParser parser() {
-        return FACTORY.parser();
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultJwtParser");
     }
 
     /**
@@ -138,6 +138,6 @@ public static JwtParserBuilder parserBuilder() {
      * strings.
      */
     public static JwtBuilder builder() {
-        return FACTORY.builder();
+        return Classes.newInstance("io.jsonwebtoken.impl.DefaultJwtBuilder");
     }
 }

api/src/main/java/io/jsonwebtoken/lang/Services.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright (C) 2019 jsonwebtoken.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package io.jsonwebtoken.lang;
 
 import java.util.ArrayList;
@@ -19,7 +34,7 @@ public final class Services {
      * @return An unmodifiable list with an instance of all available implementations of the SPI. No guarantee is given
      * on the order of implementations, if more than one.
      */
-    public static <T> List<T> loadAllAvailableImplementations(Class<T> spi) {
+    public static <T> List<T> loadAll(Class<T> spi) {
         ServiceLoader<T> serviceLoader = ServiceLoader.load(spi);
 
         List<T> implementations = new ArrayList<>();
@@ -38,14 +53,14 @@ public static <T> List<T> loadAllAvailableImplementations(Class<T> spi) {
      * @param spi The class of the Service Provider Interface
      * @param <T> The type of the SPI
      * @return A new instance of the service.
-     * @throws ImplementationNotFoundException When no implementation the SPI is available on the classpath.
+     * @throws UnavailableImplementationException When no implementation the SPI is available on the classpath.
      */
     public static <T> T loadFirst(Class<T> spi) {
         ServiceLoader<T> serviceLoader = ServiceLoader.load(spi);
         if (serviceLoader.iterator().hasNext()) {
             return serviceLoader.iterator().next();
         } else {
-            throw new ImplementationNotFoundException("No implementation of " + spi.getName() + " found on the classpath. Make sure to include an implementation of jjwt-api.");
+            throw new UnavailableImplementationException(spi);
         }
     }
 }

api/src/main/java/io/jsonwebtoken/lang/UnavailableImplementationException.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2019 jsonwebtoken.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.jsonwebtoken.lang;
+
+/**
+ * Exception indicating that no implementation of an jjwt-api SPI was found on the classpath.
+ */
+public class UnavailableImplementationException extends RuntimeException {
+
+    private static final String DEFAULT_NOT_FOUND_MESSAGE = "Unable to find an implementation for %s using java.util.ServiceLoader. Ensure you include a backing implementation .jar in the classpath, for example jjwt-impl.jar, or your own .jar for custom implementations.";
+
+    public UnavailableImplementationException(final Class klass) {
+        super(String.format(DEFAULT_NOT_FOUND_MESSAGE, klass));
+    }
+}