move xml parsing using SimpleXML (#857)

This breaks backward compatibility

api/src/main/java/io/minio/ErrorCode.java

@@ -16,7 +16,15 @@
 
 package io.minio;
 
+import org.simpleframework.xml.Root;
+import org.simpleframework.xml.convert.Convert;
+import org.simpleframework.xml.convert.Converter;
+import org.simpleframework.xml.stream.InputNode;
+import org.simpleframework.xml.stream.OutputNode;
+
 /** Amazon AWS S3 error codes. */
+@Root(name = "ErrorCode")
+@Convert(ErrorCode.ErrorCodeConverter.class)
 public enum ErrorCode {
   // custom error codes
   NO_SUCH_OBJECT("NoSuchKey", "Object does not exist"),
@@ -167,17 +175,24 @@ public String message() {
 
   /** Returns ErrorCode of given code string. */
   public static ErrorCode fromString(String codeString) {
-    if (codeString == null) {
-      return null;
-    }
-
     for (ErrorCode ec : ErrorCode.values()) {
       if (codeString.equals(ec.code)) {
         return ec;
       }
     }
 
-    // Unknown error code string.  Its not a standard Amazon S3 error.
-    return null;
+    throw new IllegalArgumentException("unknown error code string '" + codeString + "'");
+  }
+
+  public static class ErrorCodeConverter implements Converter<ErrorCode> {
+    @Override
+    public ErrorCode read(InputNode node) throws Exception {
+      return ErrorCode.fromString(node.getValue());
+    }
+
+    @Override
+    public void write(OutputNode node, ErrorCode errorCode) throws Exception {
+      node.setValue(errorCode.code());
+    }
   }
 }

api/src/main/java/io/minio/Result.java

@@ -22,26 +22,31 @@
 import io.minio.errors.InsufficientDataException;
 import io.minio.errors.InternalException;
 import io.minio.errors.InvalidBucketNameException;
+import io.minio.errors.XmlParserException;
 import java.io.IOException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
-import org.xmlpull.v1.XmlPullParserException;
 
 /** A container class keeps any type and exception occured. */
 public class Result<T> {
   private final T type;
   private final Exception ex;
 
-  public Result(T type, Exception ex) {
+  public Result(T type) {
     this.type = type;
+    this.ex = null;
+  }
+
+  public Result(Exception ex) {
+    this.type = null;
     this.ex = ex;
   }
 
   /** Returns given Type if exception is null, else respective exception is thrown. */
   public T get()
       throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException,
           JsonParseException, JsonMappingException, IOException, InvalidKeyException,
-          XmlPullParserException, ErrorResponseException, InternalException {
+          XmlParserException, ErrorResponseException, InternalException {
     if (ex == null) {
       return type;
     }
@@ -62,8 +67,8 @@ public T get()
       throw (InvalidKeyException) ex;
     }
 
-    if (ex instanceof XmlPullParserException) {
-      throw (XmlPullParserException) ex;
+    if (ex instanceof XmlParserException) {
+      throw (XmlParserException) ex;
     }
 
     if (ex instanceof ErrorResponseException) {

api/src/main/java/io/minio/SelectResponseStream.java

@@ -19,6 +19,7 @@
 import com.google.common.io.ByteStreams;
 import io.minio.errors.InternalException;
 import io.minio.errors.MinioException;
+import io.minio.messages.Progress;
 import io.minio.messages.Stats;
 import java.io.ByteArrayInputStream;
 import java.io.EOFException;
@@ -141,15 +142,17 @@ private boolean populate()
         new ByteArrayInputStream(data, headerLength, payloadLength);
 
     if (headerMap.get(":event-type").equals("Progress")) {
-      Stats stats = new Stats("Progress");
-      stats.parseXml(new InputStreamReader(payloadStream, StandardCharsets.UTF_8));
+      Stats stats =
+          (Stats)
+              Xml.unmarshal(
+                  Progress.class, new InputStreamReader(payloadStream, StandardCharsets.UTF_8));
       this.stats = stats;
       return false;
     }
 
     if (headerMap.get(":event-type").equals("Stats")) {
-      Stats stats = new Stats("Stats");
-      stats.parseXml(new InputStreamReader(payloadStream, StandardCharsets.UTF_8));
+      Stats stats =
+          Xml.unmarshal(Stats.class, new InputStreamReader(payloadStream, StandardCharsets.UTF_8));
       this.stats = stats;
       return false;
     }

api/src/main/java/io/minio/Xml.java

@@ -0,0 +1,82 @@
+/*
+ * MinIO Java SDK for Amazon S3 Compatible Cloud Storage,
+ * (C) 2020 MinIO, 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 io.minio;
+
+import io.minio.errors.XmlParserException;
+import java.io.Reader;
+import java.io.StringReader;
+import java.io.StringWriter;
+import org.simpleframework.xml.Serializer;
+import org.simpleframework.xml.convert.AnnotationStrategy;
+import org.simpleframework.xml.core.Persister;
+
+public class Xml {
+  /**
+   * This marshal method will traverse the provided object checking for field annotations in order
+   * to compose the XML data.
+   */
+  public static String marshal(Object source) throws XmlParserException {
+    try {
+      Serializer serializer = new Persister(new AnnotationStrategy());
+      StringWriter writer = new StringWriter();
+      serializer.write(source, writer);
+      return writer.toString();
+    } catch (Exception e) {
+      throw new XmlParserException(e);
+    }
+  }
+
+  /**
+   * This unmarshal method will read the contents of the XML document from the provided source and
+   * populate the object with the values deserialized.
+   */
+  public static <T> T unmarshal(Class<? extends T> type, Reader source) throws XmlParserException {
+    try {
+      Serializer serializer = new Persister(new AnnotationStrategy());
+      return serializer.read(type, source);
+    } catch (Exception e) {
+      throw new XmlParserException(e);
+    }
+  }
+
+  /**
+   * This unmarshal method will read the contents of the XML document from the provided source and
+   * populate the object with the values deserialized.
+   */
+  public static <T> T unmarshal(Class<? extends T> type, String source) throws XmlParserException {
+    try {
+      Serializer serializer = new Persister(new AnnotationStrategy());
+      return serializer.read(type, new StringReader(source));
+    } catch (Exception e) {
+      throw new XmlParserException(e);
+    }
+  }
+
+  /**
+   * This validate method will validate the contents of the XML document against the specified XML
+   * class schema.
+   */
+  public static boolean validate(Class type, String source) throws XmlParserException {
+    try {
+      Serializer serializer = new Persister(new AnnotationStrategy());
+      return serializer.validate(type, source);
+    } catch (Exception e) {
+      throw new XmlParserException(e);
+    }
+  }
+}

api/src/main/java/io/minio/errors/ErrorResponseException.java

@@ -47,7 +47,7 @@ public ErrorResponse errorResponse() {
   public String toString() {
     Request request = response.request();
     return "error occurred\n"
-        + errorResponse.getString()
+        + errorResponse.toString()
         + "\n"
         + "request={"
         + "method="

api/src/main/java/io/minio/messages/Buckets.java → api/src/main/java/io/minio/errors/XmlParserException.java

@@ -14,26 +14,18 @@
  * limitations under the License.
  */
 
-package io.minio.messages;
+package io.minio.errors;
 
-import com.google.api.client.util.Key;
-import java.util.LinkedList;
-import java.util.List;
-import org.xmlpull.v1.XmlPullParserException;
+public class XmlParserException extends MinioException {
+  Exception exception;
 
-/** Helper class to parse Amazon AWS S3 response XML containing list of bucket information. */
-@SuppressWarnings("WeakerAccess")
-public class Buckets extends XmlEntity {
-  @Key("Bucket")
-  private List<Bucket> bucketList = new LinkedList<>();
-
-  public Buckets() throws XmlPullParserException {
+  public XmlParserException(Exception exception) {
     super();
-    super.name = "Buckets";
+    this.exception = exception;
   }
 
-  /** Returns List of Buckets. */
-  public List<Bucket> bucketList() {
-    return bucketList;
+  @Override
+  public String toString() {
+    return exception.toString();
   }
 }

api/src/main/java/io/minio/messages/Bucket.java

@@ -16,24 +16,20 @@
 
 package io.minio.messages;
 
-import com.google.api.client.util.Key;
-import io.minio.Time;
 import java.time.ZonedDateTime;
-import org.xmlpull.v1.XmlPullParserException;
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.Root;
 
-/** Helper class to parse Amazon AWS S3 response XML containing bucket information. */
-@SuppressWarnings("SameParameterValue")
-public class Bucket extends XmlEntity {
-  @Key("Name")
+/** Helper class to denote bucket information for ListAllMyBucketsResult. */
+@Root(name = "Bucket", strict = false)
+public class Bucket {
+  @Element(name = "Name")
   private String name;
 
-  @Key("CreationDate")
-  private String creationDate;
+  @Element(name = "CreationDate")
+  private ResponseDate creationDate;
 
-  public Bucket() throws XmlPullParserException {
-    super();
-    super.name = "Bucket";
-  }
+  public Bucket() {}
 
   /** Returns bucket name. */
   public String name() {
@@ -42,6 +38,6 @@ public String name() {
 
   /** Returns creation date. */
   public ZonedDateTime creationDate() {
-    return ZonedDateTime.parse(creationDate, Time.RESPONSE_DATE_FORMAT);
+    return creationDate.zonedDateTime();
   }
 }

api/src/main/java/io/minio/messages/CloudFunctionConfiguration.java

@@ -16,38 +16,17 @@
 
 package io.minio.messages;
 
-import com.google.api.client.util.Key;
-import java.util.LinkedList;
-import java.util.List;
-import org.xmlpull.v1.XmlPullParserException;
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.Root;
 
-/** Helper class to parse Amazon AWS S3 response XML containing cloud function configuration. */
-public class CloudFunctionConfiguration extends XmlEntity {
-  @Key("Id")
-  private String id;
-
-  @Key("CloudFunction")
+/** Helper class to denote CloudFunction configuration of NotificationConfiguration. */
+@Root(name = "CloudFunctionConfiguration", strict = false)
+public class CloudFunctionConfiguration extends NotificationCommonConfiguration {
+  @Element(name = "CloudFunction")
   private String cloudFunction;
 
-  @Key("Event")
-  private List<String> events = new LinkedList<>();
-
-  @Key("Filter")
-  private Filter filter;
-
-  public CloudFunctionConfiguration() throws XmlPullParserException {
+  public CloudFunctionConfiguration() {
     super();
-    super.name = "CloudFunctionConfiguration";
-  }
-
-  /** Returns id. */
-  public String id() {
-    return id;
-  }
-
-  /** Sets id. */
-  public void setId(String id) {
-    this.id = id;
   }
 
   /** Returns cloudFunction. */
@@ -59,24 +38,4 @@ public String cloudFunction() {
   public void setCloudFunction(String cloudFunction) {
     this.cloudFunction = cloudFunction;
   }
-
-  /** Returns events. */
-  public List<EventType> events() throws IllegalArgumentException {
-    return EventType.fromStringList(events);
-  }
-
-  /** Sets event. */
-  public void setEvents(List<EventType> events) {
-    this.events = EventType.toStringList(events);
-  }
-
-  /** Returns filter. */
-  public Filter filter() {
-    return filter;
-  }
-
-  /** Sets filter. */
-  public void setFilter(Filter filter) {
-    this.filter = filter;
-  }
 }