Refactor EppXmlTransformer to be in the model/ package

This will allow us to perform the OT&E history verification
in the model/ package as well so that it can be used both
by both the UI and the command line tool.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=225007167

java/google/registry/model/EppResourceUtils.java

@@ -402,13 +402,5 @@ public final class EppResourceUtils {
     return queryForLinkedDomains(key, now).limit(1).count() > 0;
   }
 
-  /** Exception to throw when failing to parse a repo id. */
-  public static class InvalidRepoIdException extends Exception {
-
-    public InvalidRepoIdException(String message) {
-      super(message);
-    }
-  }
-
   private EppResourceUtils() {}
 }

java/google/registry/model/eppcommon/EppXmlTransformer.java

@@ -0,0 +1,95 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// 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 google.registry.model.eppcommon;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableList;
+import google.registry.model.ImmutableObject;
+import google.registry.model.eppinput.EppInput;
+import google.registry.model.eppoutput.EppOutput;
+import google.registry.xml.ValidationMode;
+import google.registry.xml.XmlException;
+import google.registry.xml.XmlTransformer;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+
+/** {@link XmlTransformer} for marshalling to and from the Epp model classes.  */
+public class EppXmlTransformer  {
+
+  // Hardcoded XML schemas, ordered with respect to dependency.
+  private static final ImmutableList<String> SCHEMAS = ImmutableList.of(
+      "eppcom.xsd",
+      "epp.xsd",
+      "contact.xsd",
+      "host.xsd",
+      "domain.xsd",
+      "rgp.xsd",
+      "secdns.xsd",
+      "fee06.xsd",
+      "fee11.xsd",
+      "fee12.xsd",
+      "metadata.xsd",
+      "mark.xsd",
+      "dsig.xsd",
+      "smd.xsd",
+      "launch.xsd",
+      "allocate.xsd",
+      "superuser.xsd",
+      "allocationToken-1.0.xsd");
+
+  private static final XmlTransformer INPUT_TRANSFORMER =
+      new XmlTransformer(SCHEMAS, EppInput.class);
+
+  private static final XmlTransformer OUTPUT_TRANSFORMER =
+      new XmlTransformer(SCHEMAS, EppOutput.class);
+
+  public static void validateOutput(String xml) throws XmlException {
+    OUTPUT_TRANSFORMER.validate(xml);
+  }
+
+  /**
+   * Unmarshal bytes into Epp classes.
+   *
+   * @param clazz type to return, specified as a param to enforce typesafe generics
+   */
+  public static <T> T unmarshal(Class<T> clazz, byte[] bytes) throws XmlException {
+    return INPUT_TRANSFORMER.unmarshal(clazz, new ByteArrayInputStream(bytes));
+  }
+
+  private static byte[] marshal(
+      XmlTransformer transformer,
+      ImmutableObject root,
+      ValidationMode validation) throws XmlException {
+    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+    transformer.marshal(root, byteArrayOutputStream, UTF_8, validation);
+    return byteArrayOutputStream.toByteArray();
+  }
+
+  public static byte[] marshal(EppOutput root, ValidationMode validation) throws XmlException {
+    return marshal(OUTPUT_TRANSFORMER, root, validation);
+  }
+
+  @VisibleForTesting
+  public static byte[] marshalInput(EppInput root, ValidationMode validation) throws XmlException {
+    return marshal(INPUT_TRANSFORMER, root, validation);
+  }
+
+  @VisibleForTesting
+  public static void validateInput(String xml) throws XmlException {
+    INPUT_TRANSFORMER.validate(xml);
+  }
+}