Implement XEP-0444: Message Reactions in Smack

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/ReactionsListener.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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 org.jivesoftware.smackx.reactions;
+
+import org.jivesoftware.smack.packet.Message;
+
+import org.jivesoftware.smackx.reactions.element.ReactionsElement;
+
+public interface ReactionsListener {
+
+    /**
+     * Listener method that gets called when a {@link Message} containing a {@link ReactionsElement} is received.
+     * @param reactionsElement reactionsElement
+     * @param message message
+     */
+    void onReactionReceived(Message message, ReactionsElement reactionsElement);
+
+}

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/element/Reaction.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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 org.jivesoftware.smackx.reactions.element;
+
+import org.jivesoftware.smack.packet.ExtensionElement;
+import org.jivesoftware.smack.packet.Message;
+import org.jivesoftware.smack.packet.StreamOpen;
+import org.jivesoftware.smack.packet.XmlEnvironment;
+import org.jivesoftware.smack.util.XmlStringBuilder;
+
+/**
+ * Represents a reaction in the form of an emoji to be associated with a message in XMPP. This class
+ * is used to handle the individual reaction data, including the emoji and its associated message.
+ * It is an extension element used in XMPP messages.
+ *
+ * @see ExtensionElement
+ * @see Message
+ */
+public class Reaction implements ExtensionElement {
+
+    public static final String ELEMENT = "reaction";
+    public static final String NAMESPACE = StreamOpen.CLIENT_NAMESPACE;
+
+    private final String emoji;
+
+    /**
+     * Constructs a new Reaction with the specified emoji.
+     *
+     * @param emoji The emoji representing the reaction.
+     */
+    public Reaction(String emoji) {
+        this.emoji = emoji;
+    }
+
+    /**
+     * Retrieves the emoji associated with this reaction.
+     *
+     * @return The emoji as a string.
+     */
+    public String getEmoji() {
+        return emoji;
+    }
+
+    /**
+     * Returns the namespace for this extension element. As the namespace is empty, it returns an empty string.
+     *
+     * @return The namespace of the reaction element, which is an empty string.
+     */
+    @Override
+    public String getNamespace() {
+        return NAMESPACE;
+    }
+
+    /**
+     * Returns the name of the XML element for this reaction, which is "reaction".
+     *
+     * @return The name of the XML element, which is "reaction".
+     */
+    @Override
+    public String getElementName() {
+        return ELEMENT;
+    }
+
+    /**
+     * Converts this Reaction into an XML representation that can be included in an XMPP message.
+     *
+     * @param xmlEnvironment The XML environment for serializing the element.
+     * @return The XML string builder containing the XML representation of the reaction element.
+     */
+    @Override
+    public CharSequence toXML(XmlEnvironment xmlEnvironment) {
+        XmlStringBuilder xml = new XmlStringBuilder(this, xmlEnvironment);
+        if (getEmoji() == null) {
+            xml.closeEmptyElement();
+        } else {
+            xml.rightAngleBracket();
+            xml.append(getEmoji());
+            xml.closeElement(this);
+        }
+        return xml;
+    }
+
+    /**
+     * Retrieves the Reaction extension from an XMPP message.
+     *
+     * @param message The XMPP message from which to extract the reaction.
+     * @return The Reaction extension from the message, or {@code null} if not present.
+     */
+    public static Reaction fromMessage(Message message) {
+        return message.getExtension(Reaction.class);
+    }
+}

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/element/ReactionsElement.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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 org.jivesoftware.smackx.reactions.element;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.jivesoftware.smack.packet.ExtensionElement;
+import org.jivesoftware.smack.packet.Message;
+import org.jivesoftware.smack.packet.XmlEnvironment;
+import org.jivesoftware.smack.util.XmlStringBuilder;
+
+/**
+ * Represents the reactions element in an XMPP message. This class is used to manage and serialize
+ * the list of reactions associated with a message, including the reactions' emojis and their identifiers.
+ * It is used as an extension element in XMPP messages to allow reactions to be sent and received.
+ *
+ * @see Reaction
+ * @see Message
+ * @see ExtensionElement
+ */
+public class ReactionsElement implements ExtensionElement {
+
+    public static final String ELEMENT = "reactions";
+    public static final String NAMESPACE = "urn:xmpp:reactions:0";
+
+    private final List<Reaction> reactions;
+    private final String id;
+
+    /**
+     * Constructs a new ReactionsElement with a list of reactions and an identifier.
+     *
+     * @param reactions A list of reactions associated with a message.
+     * @param id The ID of the message being reacted to.
+     */
+    public ReactionsElement(List<Reaction> reactions, String id) {
+        this.reactions = Collections.unmodifiableList(reactions);
+        this.id = id;
+    }
+
+    /**
+     * Retrieves the list of reactions in this element.
+     *
+     * @return The list of reactions.
+     */
+    public List<Reaction> getReactions() {
+        return reactions;
+    }
+
+    /**
+     * Retrieves the ID of the original message being reacted to.
+     *
+     * @return The ID of the original message.
+     */
+    public String getId() {
+        return id;
+    }
+
+    /**
+     * Returns the namespace for this extension element.
+     *
+     * @return The namespace of the reactions element.
+     */
+    @Override
+    public String getNamespace() {
+        return NAMESPACE;
+    }
+
+    /**
+     * Returns the name of the XML element associated with this extension.
+     *
+     * @return The element name for this extension, which is "reactions".
+     */
+    @Override
+    public String getElementName() {
+        return ELEMENT;
+    }
+
+    /**
+     * Converts this ReactionsElement into an XML representation that can be included in an XMPP message.
+     *
+     * @param xmlEnvironment The XML environment for serialization.
+     * @return The XML string builder with the XML representation of the element.
+     */
+    @Override
+    public XmlStringBuilder toXML(XmlEnvironment xmlEnvironment) {
+        XmlStringBuilder xml = new XmlStringBuilder(this);
+        xml.attribute("id", id);
+
+        xml.rightAngleBracket();
+        for (Reaction reaction : reactions) {
+            if (reaction != null) {
+                xml.append(reaction.toXML());
+            }
+        }
+        xml.closeElement(this);
+        return xml;
+    }
+
+    /**
+     * Retrieves the ReactionsElement from an XMPP message.
+     *
+     * @param message The XMPP message from which the reactions element is extracted.
+     * @return The ReactionsElement from the message, or {@code null} if not present.
+     */
+    public static ReactionsElement fromMessage(Message message) {
+        return message.getExtension(ReactionsElement.class);
+    }
+}

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/element/package-info.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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.
+ */
+/**
+ * Smacks implementation of XEP-0444: Message Reactions.
+ */
+package org.jivesoftware.smackx.reactions.element;

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/filter/ReactionsFilter.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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 org.jivesoftware.smackx.reactions.filter;
+
+import org.jivesoftware.smack.filter.StanzaExtensionFilter;
+import org.jivesoftware.smack.filter.StanzaFilter;
+
+import org.jivesoftware.smackx.reactions.element.ReactionsElement;
+
+/**
+ * Message Reactions filter class.
+ *
+ * @see <a href="http://xmpp.org/extensions/xep-0313.html">XEP-0444: Message
+ *      Reactions</a>
+ * @author Ismael Nunes Campos
+ *
+ */
+public final class ReactionsFilter extends StanzaExtensionFilter {
+
+    public static final StanzaFilter INSTANCE = new ReactionsFilter(ReactionsElement.ELEMENT, ReactionsElement.NAMESPACE);
+
+    private ReactionsFilter(String element, String namespace) {
+        super(element, namespace);
+    }
+}

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/filter/package-info.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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.
+ */
+/**
+ * Chat Markers elements (XEP-0444).
+ *
+ * @see <a href="https://xmpp.org/extensions/xep-0444.html">XEP-0444: Message
+ *      Reactions</a>
+ *
+ */
+package org.jivesoftware.smackx.reactions.filter;

smack-experimental/src/main/java/org/jivesoftware/smackx/reactions/package-info.java

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+/**
+ *
+ * Copyright 2025 Ismael Nunes Campos
+ *
+ * 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.
+ */
+
+/**
+ * Smack's API for XEP-0444: Message Reactions.
+ */
+package org.jivesoftware.smackx.reactions;