Handle command error

-package pl.itcrowd.youtrack.api;
-
-import org.apache.commons.io.IOUtils;
-import pl.itcrowd.youtrack.api.rest.ObjectFactory;
-
-import javax.xml.bind.JAXBContext;
-import javax.xml.bind.JAXBElement;
-import javax.xml.bind.JAXBException;
-import java.io.IOException;
-import java.io.Reader;
-import java.io.StringReader;
-
-//TODO methods from this class should be probably merged with YoutrackUnmarshaller
-public final class ErrorUnmarshaller {
-
-    public static String unmarshal(String string) throws JAXBException, IOException
-    {
-        return unmarshal(new StringReader(string));
-    }
-
-    public static String unmarshal(Reader reader) throws JAXBException, IOException
-    {
-        String content = IOUtils.toString(reader);
-        try {
-            JAXBContext jaxbContext = JAXBContext.newInstance(ObjectFactory.class);
-            @SuppressWarnings("unchecked")
-            final JAXBElement<String> element = (JAXBElement<String>) jaxbContext.createUnmarshaller().unmarshal(new StringReader(content));
-            return element.getValue();
-        } catch (JAXBException e) {
-//            TODO we need logging here
-            System.err.println("Cannot unmarshal input stream.\n" + content + e);
-            throw e;
-        }
-    }
-
-    private ErrorUnmarshaller()
-    {
-    }
-}

@@ -345,13 +345,14 @@ public class YoutrackAPI {
 
     private String execute(HttpUriRequest request) throws IOException
     {
+        request.addHeader("Accept","application/xml");
         final HttpResponse response = httpClient.execute(request);
         final StatusLine statusLine = response.getStatusLine();
         final HttpEntity entity = response.getEntity();
         String responseText = entity == null ? null : EntityUtils.toString(entity);
         if (statusLine.getStatusCode() >= 300) {
             try {
-                final String error = ErrorUnmarshaller.unmarshal(responseText);
+                final String error = YoutrackUnmarshaller.unmarshalError(responseText);
                 throw new YoutrackErrorException(error, statusLine.getStatusCode());
             } catch (JAXBException e) {
                 LOG.error("Cannot unmarshal following response text:\n" + responseText, e);

 package pl.itcrowd.youtrack.api;
 
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import pl.itcrowd.youtrack.api.exceptions.YoutrackAPIException;
+import pl.itcrowd.youtrack.api.rest.ErrorType;
 import pl.itcrowd.youtrack.api.rest.ObjectFactory;
 
 import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBElement;
 import javax.xml.bind.JAXBException;
+import java.io.IOException;
 import java.io.Reader;
+import java.io.Serializable;
 import java.io.StringReader;
 
 public final class YoutrackUnmarshaller {
 
+    private static Log LOG = LogFactory.getLog(YoutrackUnmarshaller.class);
+
+    private YoutrackUnmarshaller()
+    {
+    }
+
+    public static String unmarshalError(String string) throws JAXBException, IOException
+    {
+        return unmarshalError(new StringReader(string));
+    }
+
+    public static String unmarshalError(Reader reader) throws JAXBException, IOException
+    {
+        String content = IOUtils.toString(reader);
+        try {
+            JAXBContext jaxbContext = JAXBContext.newInstance(ObjectFactory.class);
+            @SuppressWarnings("unchecked")
+            final JAXBElement<ErrorType> element = (JAXBElement<ErrorType>) jaxbContext.createUnmarshaller().unmarshal(new StringReader(content));
+            final ErrorType value = element.getValue();
+            final int contentSize = value.getContent().size();
+            if (contentSize == 0) {
+                return "";
+            } else if (contentSize == 1) {
+                final Serializable serializable = value.getContent().get(0);
+                if (serializable instanceof JAXBElement) {
+                    if ("message".equals(((JAXBElement) serializable).getName().getLocalPart())) {
+                        final Object messageValue = ((JAXBElement) serializable).getValue();
+                        return messageValue == null ? "" : messageValue.toString();
+                    }
+                } else {
+                    return serializable == null ? "" : serializable.toString();
+                }
+            } else if (contentSize == 2) {
+                for (Serializable serializable : value.getContent()) {
+                    if (serializable instanceof JAXBElement) {
+                        if ("message".equals(((JAXBElement) serializable).getName().getLocalPart())) {
+                            final Object messageValue = ((JAXBElement) serializable).getValue();
+                            return messageValue == null ? "" : messageValue.toString();
+                        }
+                    }
+                }
+            }
+            throw new YoutrackAPIException("Cannot unserialize error.\n" + content);
+        } catch (JAXBException e) {
+            LOG.error("Cannot unmarshal error.\n" + content, e);
+            throw e;
+        }
+    }
+
     public static Object unmarshall(String string) throws JAXBException
     {
         return unmarshall(new StringReader(string));
@@ -18,8 +75,4 @@ public final class YoutrackUnmarshaller {
     {
         return JAXBContext.newInstance(ObjectFactory.class).createUnmarshaller().unmarshal(reader);
     }
-
-    private YoutrackUnmarshaller()
-    {
-    }
 }

@@ -108,8 +108,8 @@ public class Comment {
      * <p/>
      * Objects of the following type(s) are allowed in the list
      * {@link JAXBElement }{@code <}{@link Comment.Value }{@code >}
-     * {@link JAXBElement }{@code <}{@link String }{@code >}
      * {@link String }
+     * {@link JAXBElement }{@code <}{@link String }{@code >}
      */
     public List<Serializable> getContent()
     {

+//
+// This file was generated by the JavaTM Architecture for XML Binding(JAXB) Reference Implementation, vhudson-jaxb-ri-2.1-833 
+// See <a href="http://java.sun.com/xml/jaxb">http://java.sun.com/xml/jaxb</a> 
+// Any modifications to this file will be lost upon recompilation of the source schema. 
+//
+package pl.itcrowd.youtrack.api.rest;
+
+import javax.xml.bind.JAXBElement;
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlElementRef;
+import javax.xml.bind.annotation.XmlElementRefs;
+import javax.xml.bind.annotation.XmlMixed;
+import javax.xml.bind.annotation.XmlType;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * <p>Java class for errorType complex type.
+ * <p/>
+ * <p>The following schema fragment specifies the expected content contained within this class.
+ * <p/>
+ * <pre>
+ * &lt;complexType name="errorType">
+ *   &lt;complexContent>
+ *     &lt;restriction base="{http://www.w3.org/2001/XMLSchema}anyType">
+ *       &lt;sequence>
+ *         &lt;element name="message" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/>
+ *         &lt;element name="field" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/>
+ *       &lt;/sequence>
+ *     &lt;/restriction>
+ *   &lt;/complexContent>
+ * &lt;/complexType>
+ * </pre>
+ */
+@XmlAccessorType(XmlAccessType.FIELD)
+@XmlType(name = "errorType", propOrder = {"content"})
+public class ErrorType {
+
+    @XmlElementRefs({@XmlElementRef(name = "message", type = JAXBElement.class), @XmlElementRef(name = "field", type = JAXBElement.class)})
+    @XmlMixed
+    protected List<Serializable> content;
+
+    /**
+     * Gets the value of the content property.
+     * <p/>
+     * <p/>
+     * This accessor method returns a reference to the live list,
+     * not a snapshot. Therefore any modification you make to the
+     * returned list will be present inside the JAXB object.
+     * This is why there is not a <CODE>set</CODE> method for the content property.
+     * <p/>
+     * <p/>
+     * For example, to add a new item, do as follows:
+     * <pre>
+     *    getContent().add(newItem);
+     * </pre>
+     * <p/>
+     * <p/>
+     * <p/>
+     * Objects of the following type(s) are allowed in the list
+     * {@link JAXBElement }{@code <}{@link String }{@code >}
+     * {@link String }
+     * {@link JAXBElement }{@code <}{@link String }{@code >}
+     */
+    public List<Serializable> getContent()
+    {
+        if (content == null) {
+            content = new ArrayList<Serializable>();
+        }
+        return this.content;
+    }
+}

@@ -37,7 +37,7 @@ import java.util.List;
 @XmlType(name = "issueType", propOrder = {"fieldOrComment"})
 public class Issue {
 
-    @XmlElements({@XmlElement(name = "comment", type = Comment.class), @XmlElement(name = "field", type = Field.class)})
+    @XmlElements({@XmlElement(name = "field", type = Field.class), @XmlElement(name = "comment", type = Comment.class)})
     protected List<Object> fieldOrComment;
 
     @XmlAttribute
@@ -61,8 +61,8 @@ public class Issue {
      * <p/>
      * <p/>
      * Objects of the following type(s) are allowed in the list
-     * {@link Comment }
      * {@link Field }
+     * {@link Comment }
      */
     public List<Object> getFieldOrComment()
     {

@@ -38,6 +38,10 @@ public class ObjectFactory {
 
     private final static QName _CommentValue_QNAME = new QName("", "value");
 
+    private final static QName _ErrorTypeField_QNAME = new QName("", "field");
+
+    private final static QName _ErrorTypeMessage_QNAME = new QName("", "message");
+
     /**
      * Create a new ObjectFactory that can be used to create new instances of schema derived classes for package: pl.itcrowd.youtrack.api.rest
      */
@@ -46,27 +50,27 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link Comment.Value }
+     * Create an instance of {@link Field }
      */
-    public Comment.Value createCommentValue()
+    public Field createField()
     {
-        return new Comment.Value();
+        return new Field();
     }
 
     /**
-     * Create an instance of {@link EnumerationValue }
+     * Create an instance of {@link Enumeration }
      */
-    public EnumerationValue createEnumerationValue()
+    public Enumeration createEnumeration()
     {
-        return new EnumerationValue();
+        return new Enumeration();
     }
 
     /**
-     * Create an instance of {@link Issue }
+     * Create an instance of {@link User }
      */
-    public Issue createIssue()
+    public User createUser()
     {
-        return new Issue();
+        return new User();
     }
 
     /**
@@ -78,59 +82,67 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link User }
+     * Create an instance of {@link Issues }
      */
-    public User createUser()
+    public Issues createIssues()
     {
-        return new User();
+        return new Issues();
     }
 
     /**
-     * Create an instance of {@link Issues }
+     * Create an instance of {@link AssigneeList }
      */
-    public Issues createIssues()
+    public AssigneeList createAssigneeList()
     {
-        return new Issues();
+        return new AssigneeList();
     }
 
     /**
-     * Create an instance of {@link Field }
+     * Create an instance of {@link Field.Value }
      */
-    public Field createField()
+    public Field.Value createFieldValue()
     {
-        return new Field();
+        return new Field.Value();
     }
 
     /**
-     * Create an instance of {@link Comment }
+     * Create an instance of {@link AssigneeType }
      */
-    public Comment createComment()
+    public AssigneeType createAssigneeType()
     {
-        return new Comment();
+        return new AssigneeType();
     }
 
     /**
-     * Create an instance of {@link AssigneeList.Assignees }
+     * Create an instance of {@link ErrorType }
      */
-    public AssigneeList.Assignees createAssigneeListAssignees()
+    public ErrorType createErrorType()
     {
-        return new AssigneeList.Assignees();
+        return new ErrorType();
     }
 
     /**
-     * Create an instance of {@link Enumeration }
+     * Create an instance of {@link AssignedByType }
      */
-    public Enumeration createEnumeration()
+    public AssignedByType createAssignedByType()
     {
-        return new Enumeration();
+        return new AssignedByType();
     }
 
     /**
-     * Create an instance of {@link AssigneeList }
+     * Create an instance of {@link EnumerationValue }
      */
-    public AssigneeList createAssigneeList()
+    public EnumerationValue createEnumerationValue()
     {
-        return new AssigneeList();
+        return new EnumerationValue();
+    }
+
+    /**
+     * Create an instance of {@link AssigneeList.Assignees }
+     */
+    public AssigneeList.Assignees createAssigneeListAssignees()
+    {
+        return new AssigneeList.Assignees();
     }
 
     /**
@@ -142,36 +154,36 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link Field.Value }
+     * Create an instance of {@link Comment }
      */
-    public Field.Value createFieldValue()
+    public Comment createComment()
     {
-        return new Field.Value();
+        return new Comment();
     }
 
     /**
-     * Create an instance of {@link AssignedByType }
+     * Create an instance of {@link Comment.Value }
      */
-    public AssignedByType createAssignedByType()
+    public Comment.Value createCommentValue()
     {
-        return new AssignedByType();
+        return new Comment.Value();
     }
 
     /**
-     * Create an instance of {@link AssigneeType }
+     * Create an instance of {@link Issue }
      */
-    public AssigneeType createAssigneeType()
+    public Issue createIssue()
     {
-        return new AssigneeType();
+        return new Issue();
     }
 
     /**
-     * Create an instance of {@link JAXBElement }{@code <}{@link String }{@code >}}
+     * Create an instance of {@link JAXBElement }{@code <}{@link ErrorType }{@code >}}
      */
     @XmlElementDecl(namespace = "", name = "error")
-    public JAXBElement<String> createError(String value)
+    public JAXBElement<ErrorType> createError(ErrorType value)
     {
-        return new JAXBElement<String>(_Error_QNAME, String.class, null, value);
+        return new JAXBElement<ErrorType>(_Error_QNAME, ErrorType.class, null, value);
     }
 
     /**
@@ -218,4 +230,22 @@ public class ObjectFactory {
     {
         return new JAXBElement<Comment.Value>(_CommentValue_QNAME, Comment.Value.class, Comment.class, value);
     }
+
+    /**
+     * Create an instance of {@link JAXBElement }{@code <}{@link String }{@code >}}
+     */
+    @XmlElementDecl(namespace = "", name = "field", scope = ErrorType.class)
+    public JAXBElement<String> createErrorTypeField(String value)
+    {
+        return new JAXBElement<String>(_ErrorTypeField_QNAME, String.class, ErrorType.class, value);
+    }
+
+    /**
+     * Create an instance of {@link JAXBElement }{@code <}{@link String }{@code >}}
+     */
+    @XmlElementDecl(namespace = "", name = "message", scope = ErrorType.class)
+    public JAXBElement<String> createErrorTypeMessage(String value)
+    {
+        return new JAXBElement<String>(_ErrorTypeMessage_QNAME, String.class, ErrorType.class, value);
+    }
 }

 <?xml version="1.0" encoding="UTF-8"?>
 <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
-    <xs:element name="error" type="xs:string"/>
+
+    <xs:include schemaLocation="types.xsd"/>
+
+    <xs:element name="error" type="errorType"/>
+
 </xs:schema>
\ No newline at end of file

@@ -30,6 +30,13 @@
         </xs:simpleContent>
     </xs:complexType>
 
+    <xs:complexType name="errorType" mixed="true">
+        <xs:sequence>
+            <xs:element type="xs:string" name="message" minOccurs="0"/>
+            <xs:element type="xs:string" name="field" minOccurs="0"/>
+        </xs:sequence>
+    </xs:complexType>
+
     <xs:complexType name="fieldType">
         <xs:sequence id="value" maxOccurs="unbounded" minOccurs="0">
             <xs:element name="value">

+package pl.itcrowd.youtrack.api.rest;
+
+import org.junit.Test;
+import pl.itcrowd.youtrack.api.YoutrackUnmarshaller;
+import pl.itcrowd.youtrack.api.exceptions.YoutrackAPIException;
+
+import javax.xml.bind.JAXBException;
+import java.io.IOException;
+
+import static junit.framework.Assert.assertEquals;
+
+public class YoutrackUnmarshallerTest {
+
+    @Test
+    public void unmarshalEmptyError() throws JAXBException, IOException
+    {
+//        Given
+        final String extendedErrorResponse = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><error></error>";
+
+//        When
+        final String errorText = YoutrackUnmarshaller.unmarshalError(extendedErrorResponse);
+
+//        THen
+        assertEquals("", errorText);
+    }
+
+    @Test
+    public void unmarshalError() throws JAXBException, IOException
+    {
+//        Given
+        final String extendedErrorResponse = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><error>Estimated completion time</error>";
+
+//        When
+        final String errorText = YoutrackUnmarshaller.unmarshalError(extendedErrorResponse);
+
+//        THen
+        assertEquals("Estimated completion time", errorText);
+    }
+
+    @Test
+    public void unmarshalExtendedError() throws JAXBException, IOException
+    {
+//        Given
+        final String extendedErrorResponse = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><error><message>Estimate task before starting work on it</message><field>Estimated completion time</field></error>";
+
+//        When
+        final String errorText = YoutrackUnmarshaller.unmarshalError(extendedErrorResponse);
+
+//        Then
+        assertEquals("Estimate task before starting work on it", errorText);
+    }
+
+    @Test
+    public void unmarshalExtendedErrorWithMessageOnly() throws JAXBException, IOException
+    {
+//        Given
+        final String extendedErrorResponse = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><error><message>Estimate task before starting work on it</message></error>";
+
+//        When
+        final String errorText = YoutrackUnmarshaller.unmarshalError(extendedErrorResponse);
+
+//        Then
+        assertEquals("Estimate task before starting work on it", errorText);
+    }
+
+    @Test
+    public void unmarshalExtendedErrorWithEmptyMessage() throws JAXBException, IOException
+    {
+//        Given
+        final String extendedErrorResponse = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><error><message></message><field>Estimated completion time</field></error>";
+
+//        When
+        final String errorText = YoutrackUnmarshaller.unmarshalError(extendedErrorResponse);
+
+//        Then
+        assertEquals("", errorText);
+    }
+
+    @Test(expected = YoutrackAPIException.class)
+    public void unmarshalExtendedErrorWithoutMessage() throws JAXBException, IOException
+    {
+//        Given
+        final String extendedErrorResponse = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><error><field>Estimated completion time</field></error>";
+
+//        When
+        YoutrackUnmarshaller.unmarshalError(extendedErrorResponse);
+    }
+}