Issue JERSEY-1220 fixed.

Improved string to object conversion for request parameters.

Change-Id: I5fbff9e5f0fe397fdaf69ecab82b04ac94995eef

core-server/src/main/java/org/glassfish/jersey/server/internal/inject/AbstractStringReaderExtractor.java

@@ -89,7 +89,11 @@ public String getDefaultValueString() {
     }
 
     protected final T fromString(String value) {
-        return valueReader.fromString(value);
+        T result = valueReader.fromString(value);
+        if (result == null) {
+            return defaultValue();
+        }
+        return result;
     }
 
     protected final boolean isDefaultValueRegistered() {
@@ -99,4 +103,4 @@ protected final boolean isDefaultValueRegistered() {
     protected final T defaultValue() {
         return (defaultValueString == null) ? null : valueReader.fromString(defaultValueString);
     }
-}
+}

core-server/src/main/java/org/glassfish/jersey/server/internal/inject/CollectionExtractor.java

@@ -73,7 +73,7 @@ public Collection<T> extract(MultivaluedMap<String, String> parameters) {
         final Collection<T> valueList = getInstance();
         if (stringList != null) {
             for (String v : stringList) {
-                valueList.add((v.length() == 0) ? null : fromString(v));
+                valueList.add(fromString(v));
             }
         } else if (isDefaultValueRegistered()) {
             valueList.add(defaultValue());

core-server/src/main/java/org/glassfish/jersey/server/internal/inject/StringCollectionExtractor.java

@@ -52,7 +52,7 @@
 /**
  * Extract parameter value as a specific {@code String} Java collection type.
  * <p />
- * This class can be seen as a special, optimized, case of {@link CollectionStringReaderExtractor}.
+ * This class can be seen as a special, optimized, case of {@link CollectionExtractor}.
  *
  * @author Paul Sandoz
  * @author Marek Potociar (marek.potociar at oracle.com)

core-server/src/main/java/org/glassfish/jersey/server/internal/inject/StringReaderProviders.java

@@ -75,6 +75,10 @@ public T fromString(String value) {
             try {
                 return _fromString(value);
             } catch (InvocationTargetException ex) {
+                // if the value is an empty string, return null
+                if (value.length() == 0) {
+                    return null;
+                }
                 Throwable target = ex.getTargetException();
                 if (target instanceof WebApplicationException) {
                     throw (WebApplicationException) target;

core-server/src/test/java/org/glassfish/jersey/server/internal/inject/QueryParamFromStringTest.java

@@ -40,6 +40,7 @@
 
 package org.glassfish.jersey.server.internal.inject;
 
+import java.util.List;
 import java.util.concurrent.ExecutionException;
 
 import javax.ws.rs.GET;
@@ -66,6 +67,11 @@ private Parameter(CharSequence cs) {
         public static Parameter fromString(String s) {
             return new Parameter(s + "fromString");
         }
+
+        @Override
+        public String toString() {
+            return s;
+        }
     }
 
     @Path("/")
@@ -76,6 +82,22 @@ public String doGet(
             assertEquals("3.145fromString", p.s);
             return "content";
         }
+
+        @GET
+        @Path("list")
+        public String doGet(@QueryParam("arg") List<Parameter> p) {
+            System.err.println(p.toString());
+            assertEquals("[afromString, fromString, bfromString]", p.toString());
+            return "content";
+        }
+
+        @GET
+        @Path("empty")
+        public String doGetEmpty(
+                @QueryParam("arg1") Parameter p) {
+            assertEquals("fromString", p.s);
+            return "content";
+        }
     }
 
     @Test
@@ -84,4 +106,18 @@ public void testFromStringGet() throws ExecutionException, InterruptedException
 
         _test("/?arg1=3.145");
     }
+
+    @Test
+    public void testListFromStringGet() throws ExecutionException, InterruptedException {
+        initiateWebApplication(ResourceString.class);
+
+        _test("/list/?arg=a&arg=&arg=b");
+    }
+
+    @Test
+    public void testFromEmptyStringGet() throws ExecutionException, InterruptedException {
+        initiateWebApplication(ResourceString.class);
+
+        _test("/empty/?arg1=");
+    }
 }

core-server/src/test/java/org/glassfish/jersey/server/internal/inject/QueryParamStringConstructorTest.java

@@ -99,6 +99,18 @@ public String doGetString(@QueryParam("args") List<BigDecimal> args) {
         }
     }
 
+    @Path("/")
+    public static class ResourceStringNull {
+        @GET
+        public String doGet(
+                @QueryParam("arg1") BigDecimal arg1,
+                @QueryParam("arg2") BigInteger arg2) {
+            assertEquals(null, arg1);
+            assertEquals(null, arg2);
+            return "content";
+        }
+    }
+
     @Path("/")
     public static class ResourceStringNullDefault {
         @GET
@@ -179,6 +191,13 @@ public void testStringConstructorListEmptyGet() throws ExecutionException, Inter
         _test("/?args&args&args", "application/stringlist");
     }
 
+    @Test
+    public void testStringConstructorNullGet() throws ExecutionException, InterruptedException {
+        initiateWebApplication(ResourceStringNull.class);
+
+        _test("/?arg1=&arg2=");
+    }
+
     @Test
     public void testStringConstructorNullDefault() throws ExecutionException, InterruptedException {
         initiateWebApplication(ResourceStringNullDefault.class);