Replace ROME Propono AtomPub server with self-contained StAX implementation

app/pom.xml

@@ -54,7 +54,7 @@ limitations under the License.
         <maven-war.version>3.4.0</maven-war.version>
         <maven-surefire.version>3.5.2</maven-surefire.version>
         <maven-antrun.version>1.0b3</maven-antrun.version>
-        <rome.version>1.19.0</rome.version> <!-- locked in place since next version removes popono -->
+        <rome.version>1.19.0</rome.version> <!-- ROME core; used for feeds/planet (AtomPub no longer uses Propono) -->
         <slf4j.version>2.0.16</slf4j.version>
         <spring.version>5.3.39</spring.version>
         <spring.security.version>5.8.14</spring.security.version>
@@ -522,11 +522,12 @@ limitations under the License.
             </exclusions>
         </dependency>
 
-        <!-- todo: remove/replace propono -->
+        <!-- Used by Trackback; previously reached the classpath transitively
+             via rome-propono, now declared explicitly since propono was removed. -->
         <dependency>
-            <groupId>com.rometools</groupId>
-            <artifactId>rome-propono</artifactId>
-            <version>${rome.version}</version>
+            <groupId>commons-httpclient</groupId>
+            <artifactId>commons-httpclient</artifactId>
+            <version>3.1</version>
             <scope>compile</scope>
             <exclusions>
                 <exclusion>
@@ -592,6 +593,15 @@ limitations under the License.
             <scope>test</scope>
         </dependency>
 
+        <!-- Jing: RELAX NG validator, used to check AtomWriter output against
+             the RFC 4287 / RFC 5023 schemas in AtomSchemaValidationTest. -->
+        <dependency>
+            <groupId>com.thaiopensource</groupId>
+            <artifactId>jing</artifactId>
+            <version>20091111</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <build>

app/src/main/java/org/apache/roller/weblogger/webservices/atomprotocol/AtomCategories.java

@@ -0,0 +1,53 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  The ASF licenses this file to You
+* 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.  For additional information regarding
+* copyright in this work, please see the NOTICE file in the top level
+* directory of this distribution.
+*/
+package org.apache.roller.weblogger.webservices.atomprotocol;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An APP categories element (app:categories) describing the categories a
+ * collection accepts. When {@code fixed} is true the listed categories are the
+ * only ones allowed.
+ */
+public class AtomCategories {
+
+    private boolean fixed;
+    private String scheme;
+    private final List<AtomCategory> categories = new ArrayList<>();
+
+    public boolean isFixed() {
+        return fixed;
+    }
+
+    public void setFixed(boolean fixed) {
+        this.fixed = fixed;
+    }
+
+    public String getScheme() {
+        return scheme;
+    }
+
+    public void setScheme(String scheme) {
+        this.scheme = scheme;
+    }
+
+    public List<AtomCategory> getCategories() {
+        return categories;
+    }
+}

app/src/main/java/org/apache/roller/weblogger/webservices/atomprotocol/AtomCategory.java

@@ -0,0 +1,53 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  The ASF licenses this file to You
+* 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.  For additional information regarding
+* copyright in this work, please see the NOTICE file in the top level
+* directory of this distribution.
+*/
+package org.apache.roller.weblogger.webservices.atomprotocol;
+
+/**
+ * An atom:category element. A null {@code scheme} signifies a free-form tag;
+ * a scheme that matches the weblog category scheme signifies a weblog category.
+ */
+public class AtomCategory {
+
+    private String term;
+    private String scheme;
+    private String label;
+
+    public String getTerm() {
+        return term;
+    }
+
+    public void setTerm(String term) {
+        this.term = term;
+    }
+
+    public String getScheme() {
+        return scheme;
+    }
+
+    public void setScheme(String scheme) {
+        this.scheme = scheme;
+    }
+
+    public String getLabel() {
+        return label;
+    }
+
+    public void setLabel(String label) {
+        this.label = label;
+    }
+}

app/src/main/java/org/apache/roller/weblogger/webservices/atomprotocol/AtomCollection.java

@@ -0,0 +1,60 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  The ASF licenses this file to You
+* 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.  For additional information regarding
+* copyright in this work, please see the NOTICE file in the top level
+* directory of this distribution.
+*/
+package org.apache.roller.weblogger.webservices.atomprotocol;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An APP collection (app:collection) within a workspace.
+ */
+public class AtomCollection {
+
+    private String title;
+    private String href;
+    private List<String> accepts = new ArrayList<>();
+    private final List<AtomCategories> categories = new ArrayList<>();
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getHref() {
+        return href;
+    }
+
+    public void setHref(String href) {
+        this.href = href;
+    }
+
+    public List<String> getAccepts() {
+        return accepts;
+    }
+
+    public void setAccepts(List<String> accepts) {
+        this.accepts = accepts;
+    }
+
+    public List<AtomCategories> getCategories() {
+        return categories;
+    }
+}

app/src/main/java/org/apache/roller/weblogger/webservices/atomprotocol/AtomConstants.java

@@ -0,0 +1,42 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  The ASF licenses this file to You
+* 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.  For additional information regarding
+* copyright in this work, please see the NOTICE file in the top level
+* directory of this distribution.
+*/
+package org.apache.roller.weblogger.webservices.atomprotocol;
+
+/**
+ * Constants shared by the StAX-based AtomPub implementation.
+ */
+public final class AtomConstants {
+
+    private AtomConstants() {
+    }
+
+    /** Atom Syndication Format namespace (RFC 4287). */
+    public static final String ATOM_NS = "http://www.w3.org/2005/Atom";
+
+    /** Atom Publishing Protocol namespace (RFC 5023). */
+    public static final String APP_NS = "http://www.w3.org/2007/app";
+
+    /** Media type for an Atom entry. */
+    public static final String ENTRY_MEDIA_TYPE = "application/atom+xml;type=entry";
+
+    /** Media type for an Atom feed/collection. */
+    public static final String FEED_MEDIA_TYPE = "application/atom+xml;type=feed;charset=utf-8";
+
+    /** Media type for an APP service document. */
+    public static final String SERVICE_MEDIA_TYPE = "application/atomsvc+xml;charset=utf-8";
+}

app/src/main/java/org/apache/roller/weblogger/webservices/atomprotocol/AtomContent.java

@@ -0,0 +1,54 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  The ASF licenses this file to You
+* 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.  For additional information regarding
+* copyright in this work, please see the NOTICE file in the top level
+* directory of this distribution.
+*/
+package org.apache.roller.weblogger.webservices.atomprotocol;
+
+/**
+ * An Atom text/content construct (atom:content or atom:summary). For inline
+ * content {@code value} holds the text; for out-of-line media content
+ * {@code src} holds the source URI instead.
+ */
+public class AtomContent {
+
+    private String type;
+    private String value;
+    private String src;
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getValue() {
+        return value;
+    }
+
+    public void setValue(String value) {
+        this.value = value;
+    }
+
+    public String getSrc() {
+        return src;
+    }
+
+    public void setSrc(String src) {
+        this.src = src;
+    }
+}