SaxDecoder now decodes multiple types.

CHANGES.md

@@ -1,5 +1,6 @@
 ### Version 5.0
 * Remove support for Observable methods.
+* SaxDecoder now decodes multiple types.
 
 ### Version 4.4.1
 * Fix NullPointerException on calling equals and hashCode.

core/src/main/java/feign/codec/SAXDecoder.java

@@ -25,11 +25,52 @@ import javax.inject.Provider;
 import java.io.IOException;
 import java.io.Reader;
 import java.lang.reflect.Type;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
 import static feign.Util.checkNotNull;
 import static feign.Util.checkState;
+import static feign.Util.resolveLastTypeParameter;
+
+/**
+ * Decodes responses using SAX. Configure using the {@link SAXDecoder.Builder
+ * builder}.
+ * <p/>
+ * 
+ * <pre>
+ * &#064;Provides(type = SET)
+ * Decoder saxDecoder(Provider&lt;ContentHandlerForFoo&gt; foo, //
+ *         Provider&lt;ContentHandlerForBar&gt; bar) {
+ *     return SAXDecoder.builder() //
+ *             .addContentHandler(foo) //
+ *             .addContentHandler(bar) //
+ *             .build();
+ * }
+ * </pre>
+ */
+public class SAXDecoder implements Decoder.TextStream<Object> {
+
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  // builder as dagger doesn't support wildcard bindings, map bindings, or set bindings of providers.
+  public static class Builder {
+    private final Map<Type, Provider<? extends ContentHandlerWithResult<?>>> handlerProviders =
+        new LinkedHashMap<Type, Provider<? extends ContentHandlerWithResult<?>>>();
+
+    public Builder addContentHandler(Provider<? extends ContentHandlerWithResult<?>> handler) {
+      Type type = resolveLastTypeParameter(checkNotNull(handler, "handler").getClass(), Provider.class);
+      type = resolveLastTypeParameter(type, ContentHandlerWithResult.class);
+      this.handlerProviders.put(type, handler);
+      return this;
+    }
+
+    public SAXDecoder build() {
+      return new SAXDecoder(handlerProviders);
+    }
+  }
 
-public class SAXDecoder<T> implements Decoder.TextStream<T> {
   /* Implementations are not intended to be shared across requests. */
   public interface ContentHandlerWithResult<T> extends ContentHandler {
     /*
@@ -39,27 +80,17 @@ public class SAXDecoder<T> implements Decoder.TextStream<T> {
     T result();
   }
 
-  private final Provider<? extends ContentHandlerWithResult<T>> handlers;
+  private final Map<Type, Provider<? extends ContentHandlerWithResult<?>>> handlerProviders;
 
-  /**
-   * You must subclass this, in order to prevent type erasure on {@code T}. In
-   * addition to making a concrete type, you can also use the following form.
-   * <p/>
-   * <br>
-   * <p/>
-   * <pre>
-   * new SaxDecoder&lt;Foo&gt;(fooHandlers) {
-   * }; // note the curly braces ensures no type erasure!
-   * </pre>
-   */
-  protected SAXDecoder(Provider<? extends ContentHandlerWithResult<T>> handlers) {
-    this.handlers = checkNotNull(handlers, "handlers");
+  private SAXDecoder(Map<Type, Provider<? extends ContentHandlerWithResult<?>>> handlerProviders) {
+    this.handlerProviders = handlerProviders;
   }
 
   @Override
-  public T decode(Reader reader, Type type) throws IOException, DecodeException {
-    ContentHandlerWithResult<T> handler = handlers.get();
-    checkState(handler != null, "%s returned null for type %s", this, type);
+  public Object decode(Reader reader, Type type) throws IOException, DecodeException {
+    Provider<? extends ContentHandlerWithResult<?>> handlerProvider = handlerProviders.get(type);
+    checkState(handlerProvider != null, "type %s not in configured handlers %s", type, handlerProviders.keySet());
+    ContentHandlerWithResult<?> handler = handlerProvider.get();
     try {
       XMLReader xmlReader = XMLReaderFactory.createXMLReader();
       xmlReader.setFeature("http://xml.org/sax/features/namespaces", false);

core/src/test/java/feign/codec/SAXDecoderTest.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright 2013 Netflix, Inc.
+ *
+ * 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 feign.codec;
+
+import dagger.ObjectGraph;
+import dagger.Provides;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.Test;
+import org.xml.sax.helpers.DefaultHandler;
+
+import javax.inject.Inject;
+import javax.inject.Provider;
+import java.io.IOException;
+import java.io.StringReader;
+import java.text.ParseException;
+import java.util.Set;
+
+import static dagger.Provides.Type.SET;
+import static org.testng.Assert.assertEquals;
+
+// unbound wildcards are not currently injectable in dagger.
+@SuppressWarnings("rawtypes")
+public class SAXDecoderTest {
+
+  @dagger.Module(injects = SAXDecoderTest.class)
+  static class Module {
+    @Provides(type = SET) Decoder saxDecoder(Provider<NetworkStatusHandler> networkStatus, //
+                                             Provider<NetworkStatusStringHandler> networkStatusAsString) {
+      return SAXDecoder.builder() //
+          .addContentHandler(networkStatus) //
+          .addContentHandler(networkStatusAsString) //
+          .build();
+    }
+  }
+
+  @Inject Set<Decoder> decoders;
+
+  @BeforeClass void inject() {
+    ObjectGraph.create(new Module()).inject(this);
+  }
+
+  @Test public void parsesConfiguredTypes() throws ParseException, IOException {
+    Decoder decoder = decoders.iterator().next();
+    assertEquals(decoder.decode(new StringReader(statusFailed), NetworkStatus.class), NetworkStatus.FAILED);
+    assertEquals(decoder.decode(new StringReader(statusFailed), String.class), "Failed");
+  }
+
+  @Test(expectedExceptions = IllegalStateException.class, expectedExceptionsMessageRegExp =
+      "type int not in configured handlers \\[class .*NetworkStatus, class java.lang.String\\]")
+  public void niceErrorOnUnconfiguredType() throws ParseException, IOException {
+    Decoder decoder = decoders.iterator().next();
+    decoder.decode(new StringReader(statusFailed), int.class);
+  }
+
+  static String statusFailed = ""//
+      + "<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">\n"//
+      + "  <soap:Body>\n"//
+      + "    <ns1:getNeustarNetworkStatusResponse xmlns:ns1=\"http://webservice.api.ultra.neustar.com/v01/\">\n"//
+      + "      <NeustarNetworkStatus xmlns:ns2=\"http://schema.ultraservice.neustar.com/v01/\">Failed</NeustarNetworkStatus>\n"//
+      + "    </ns1:getNeustarNetworkStatusResponse>\n"//
+      + "  </soap:Body>\n"//
+      + "</soap:Envelope>";
+
+  static enum NetworkStatus {
+    GOOD, FAILED;
+  }
+
+  static class NetworkStatusStringHandler extends DefaultHandler implements
+      SAXDecoder.ContentHandlerWithResult<String> {
+    @Inject NetworkStatusStringHandler() {
+    }
+
+    private StringBuilder currentText = new StringBuilder();
+
+    private String status;
+
+    @Override
+    public String result() {
+      return status;
+    }
+
+    @Override
+    public void endElement(String uri, String name, String qName) {
+      if (qName.equals("NeustarNetworkStatus")) {
+        this.status = currentText.toString().trim();
+      }
+      currentText = new StringBuilder();
+    }
+
+    @Override
+    public void characters(char ch[], int start, int length) {
+      currentText.append(ch, start, length);
+    }
+  }
+
+  static class NetworkStatusHandler extends DefaultHandler implements
+      SAXDecoder.ContentHandlerWithResult<NetworkStatus> {
+    @Inject NetworkStatusHandler() {
+    }
+
+    private StringBuilder currentText = new StringBuilder();
+
+    private NetworkStatus status;
+
+    @Override
+    public NetworkStatus result() {
+      return status;
+    }
+
+    @Override
+    public void endElement(String uri, String name, String qName) {
+      if (qName.equals("NeustarNetworkStatus")) {
+        this.status = NetworkStatus.valueOf(currentText.toString().trim().toUpperCase());
+      }
+      currentText = new StringBuilder();
+    }
+
+    @Override
+    public void characters(char ch[], int start, int length) {
+      currentText.append(ch, start, length);
+    }
+  }
+}

core/src/test/java/feign/examples/IAMExample.java

@@ -23,20 +23,28 @@ import feign.RequestLine;
 import feign.RequestTemplate;
 import feign.Target;
 import feign.codec.Decoder;
-import feign.codec.Decoders;
+import feign.codec.Decoders.ApplyFirstGroup;
+import feign.codec.Decoders.TransformFirstGroup;
+import feign.codec.SAXDecoder;
+import org.xml.sax.helpers.DefaultHandler;
+
+import javax.inject.Inject;
+import javax.inject.Provider;
 
 import static dagger.Provides.Type.SET;
 
 public class IAMExample {
 
   interface IAM {
-    @RequestLine("GET /?Action=GetUser&Version=2010-05-08") String arn();
+    @RequestLine("GET /?Action=GetUser&Version=2010-05-08") Long userId();
   }
 
   public static void main(String... args) {
 
-    IAM iam = Feign.create(new IAMTarget(args[0], args[1]), new IAMModule());
-    System.out.println(iam.arn());
+    for (Object decodingApproach : new Object[]{new DecodeWithSax(), new DecodeWithRegEx()}) {
+      IAM iam = Feign.create(new IAMTarget(args[0], args[1]), decodingApproach);
+      System.out.println(iam.userId());
+    }
   }
 
   static class IAMTarget extends AWSSignatureVersion4 implements Target<IAM> {
@@ -64,9 +72,52 @@ public class IAMExample {
   }
 
   @Module(library = true)
-  static class IAMModule {
-    @Provides(type = SET) Decoder decoder() {
-      return Decoders.firstGroup("<Arn>([\\S&&[^<]]+)</Arn>");
+  static class DecodeWithRegEx {
+    @Provides(type = SET) Decoder regExDecoder() {
+      return new TransformFirstGroup<Long>("<UserId>([0-9]+)</UserId>", new ApplyFirstGroup<Long>() {
+
+        @Override public Long apply(String firstGroup) {
+          return Long.parseLong(firstGroup);
+        }
+      }) {
+      };
+    }
+  }
+
+  @Module(library = true)
+  static class DecodeWithSax {
+    @Provides(type = SET) Decoder saxDecoder(Provider<UserIdHandler> userIdHandler) {
+      return SAXDecoder.builder() //
+          .addContentHandler(userIdHandler) //
+          .build();
+    }
+  }
+
+  static class UserIdHandler extends DefaultHandler implements
+      SAXDecoder.ContentHandlerWithResult<Long> {
+    @Inject UserIdHandler() {
+    }
+
+    private StringBuilder currentText = new StringBuilder();
+
+    private Long userId;
+
+    @Override
+    public Long result() {
+      return userId;
+    }
+
+    @Override
+    public void endElement(String uri, String name, String qName) {
+      if (qName.equals("UserId")) {
+        this.userId = Long.parseLong(currentText.toString().trim());
+      }
+      currentText = new StringBuilder();
+    }
+
+    @Override
+    public void characters(char ch[], int start, int length) {
+      currentText.append(ch, start, length);
     }
   }
 }