Add UI action to render MessageTemplate with selected entities to validate parameters jmix-framework/jmix#4892

jmix-messagetemplates/messagetemplates-flowui/src/main/java/io/jmix/messagetemplatesflowui/view/messagetemplate/MessageTemplateDetailView.java

@@ -42,6 +42,7 @@
 import io.jmix.messagetemplatesflowui.kit.component.GrapesJsBlock;
 import io.jmix.messagetemplatesflowui.view.htmleditor.HtmlEditorView;
 import io.jmix.messagetemplatesflowui.view.messagetemplateparameter.MessageTemplateParameterDetailView;
+import io.jmix.messagetemplatesflowui.view.messagetemplatepreview.MessageTemplatesPreviewer;
 import org.springframework.beans.factory.annotation.Autowired;
 
 import java.nio.charset.StandardCharsets;
@@ -79,6 +80,8 @@ public class MessageTemplateDetailView extends StandardDetailView<MessageTemplat
     protected Metadata metadata;
     @Autowired
     protected AccessManager accessManager;
+    @Autowired
+    protected MessageTemplatesPreviewer messageTemplatesPreviewer;
 
     @Autowired
     protected UiProperties uiProperties;
@@ -237,4 +240,9 @@ public void parametersDataGridCreateViewConfigurer(MessageTemplateParameterDetai
     public void parametersDataGridEditViewConfigurer(MessageTemplateParameterDetailView detailView) {
         detailView.setParentTemplateParameters(getEditedEntity().getParameters());
     }
+
+    @Subscribe("previewButton")
+    public void onPreviewButtonClick(ClickEvent<JmixButton> event) {
+        messageTemplatesPreviewer.showPreview(getEditedEntity(), this);
+    }
 }

jmix-messagetemplates/messagetemplates-flowui/src/main/java/io/jmix/messagetemplatesflowui/view/messagetemplate/MessageTemplateListView.java

@@ -41,6 +41,7 @@
 import io.jmix.messagetemplates.entity.MessageTemplateParameter;
 import io.jmix.messagetemplates.entity.TemplateType;
 import io.jmix.messagetemplatesflowui.accesscontext.UiImportExportMessageTemplateContext;
+import io.jmix.messagetemplatesflowui.view.messagetemplatepreview.MessageTemplatesPreviewer;
 import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -101,6 +102,8 @@ public class MessageTemplateListView extends StandardListView<MessageTemplate> {
     protected Downloader downloader;
     @Autowired
     protected Notifications notifications;
+    @Autowired
+    protected MessageTemplatesPreviewer messageTemplatesPreviewer;
 
     protected boolean isCreatePermitted;
     protected boolean isImportExportPermitted;
@@ -146,6 +149,12 @@ public void onMessageTemplatesDataGridCopy(ActionPerformedEvent event) {
         }
     }
 
+    @Subscribe("messageTemplatesDataGrid.preview")
+    public void onMessageTemplatesDataGridPreview(ActionPerformedEvent event) {
+        MessageTemplate selectedItem = messageTemplatesDataGrid.getSingleSelectedItem();
+        messageTemplatesPreviewer.showPreview(selectedItem, this);
+    }
+
     @Subscribe("importField")
     public void onImportFileUploadSucceeded(FileUploadSucceededEvent<FileUploadField, byte[]> event) {
         byte[] fileBytes = event.getSource().getValue();

jmix-messagetemplates/messagetemplates-flowui/src/main/java/io/jmix/messagetemplatesflowui/view/messagetemplatepreview/MessageTemplatePreviewView.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2026 Haulmont.
+ *
+ * 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.jmix.messagetemplatesflowui.view.messagetemplatepreview;
+
+import com.vaadin.flow.component.ClickEvent;
+import com.vaadin.flow.component.Html;
+import com.vaadin.flow.component.orderedlayout.VerticalLayout;
+import io.jmix.flowui.UiComponents;
+import io.jmix.flowui.component.textarea.JmixTextArea;
+import io.jmix.flowui.download.DownloadFormat;
+import io.jmix.flowui.download.Downloader;
+import io.jmix.flowui.kit.component.button.JmixButton;
+import io.jmix.flowui.view.*;
+import io.jmix.messagetemplates.entity.TemplateType;
+import org.springframework.beans.factory.annotation.Autowired;
+
+import java.nio.charset.StandardCharsets;
+
+@ViewController("msgtmp_MessageTemplatePreviewView")
+@ViewDescriptor("message-template-preview-view.xml")
+@DialogMode(resizable = true)
+public class MessageTemplatePreviewView extends StandardView {
+
+    @Autowired
+    protected UiComponents uiComponents;
+    @Autowired
+    protected Downloader downloader;
+
+    @ViewComponent
+    protected VerticalLayout contentBox;
+    @ViewComponent
+    protected JmixButton openInNewTabButton;
+
+    protected TemplateType type;
+    protected String content;
+
+    @Subscribe
+    public void onInit(InitEvent event) {
+        downloader.setShowNewWindow(true);
+    }
+
+    public void setPreviewContent(TemplateType type, String content) {
+        this.type = type;
+        this.content = content;
+    }
+
+    @Subscribe
+    public void onBeforeShow(BeforeShowEvent event) {
+        if (TemplateType.HTML.equals(type)) {
+            initHtmlLayout();
+        } else {
+            initTextLayout();
+        }
+    }
+
+    protected void initHtmlLayout() {
+        openInNewTabButton.setVisible(true);
+
+        // <div> wrapping required to avoid 'HTML must contain exactly one top-level element' exception
+        Html html = new Html("<div>%s</div>".formatted(content));
+        contentBox.addAndExpand(html);
+    }
+
+    protected void initTextLayout() {
+        JmixTextArea textArea = uiComponents.create(JmixTextArea.class);
+
+        textArea.setReadOnly(true);
+        textArea.setWidth("60em");
+        textArea.setValue(content);
+        contentBox.addAndExpand(textArea);
+    }
+
+    @Subscribe("openInNewTabButton")
+    public void onOpenInNewTabButtonClick(ClickEvent<JmixButton> event) {
+        downloader.download(content.getBytes(StandardCharsets.UTF_8), "preview.html", DownloadFormat.HTML);
+    }
+}

jmix-messagetemplates/messagetemplates-flowui/src/main/java/io/jmix/messagetemplatesflowui/view/messagetemplatepreview/MessageTemplatesPreviewer.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2026 Haulmont.
+ *
+ * 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.jmix.messagetemplatesflowui.view.messagetemplatepreview;
+
+import io.jmix.core.annotation.Internal;
+import io.jmix.flowui.DialogWindows;
+import io.jmix.flowui.view.StandardOutcome;
+import io.jmix.flowui.view.View;
+import io.jmix.messagetemplates.MessageTemplatesGenerator;
+import io.jmix.messagetemplates.entity.MessageTemplate;
+import io.jmix.messagetemplatesflowui.view.parametersinputdialog.MessageTemplateParametersInputDialog;
+import org.jspecify.annotations.Nullable;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * Provides functionality for previewing {@link MessageTemplate}.
+ * <p>
+ * Allows users to enter parameters used for generating a message preview
+ * and displays the result in a dialog.
+ * <p>
+ * This is an internal component and is not intended for direct use in application code.
+ */
+@Internal
+@Component("msgtmp_MessageTemplatesPreviewer")
+public class MessageTemplatesPreviewer {
+
+    @Autowired
+    protected MessageTemplatesGenerator messageTemplatesGenerator;
+    @Autowired
+    protected DialogWindows dialogWindows;
+
+    /**
+     * Opens a preview for the specified message template.
+     * <p>
+     * If the template contains parameters, a dialog for parameter input is shown first.
+     * After confirmation, the template is generated and the result is displayed.
+     *
+     * @param messageTemplate the message template (can be {@code null})
+     * @param origin          the originating view used to open dialogs
+     */
+    public void showPreview(@Nullable MessageTemplate messageTemplate, View<?> origin) {
+        if (messageTemplate == null) {
+            return;
+        }
+
+        if (!messageTemplate.getParameters().isEmpty()) {
+            dialogWindows.view(origin, MessageTemplateParametersInputDialog.class)
+                    .withViewConfigurer(view ->
+                            view.setTemplateParameters(messageTemplate.getParameters()))
+                    .withAfterCloseListener(event -> {
+                        if (event.closedWith(StandardOutcome.SAVE)) {
+                            showTemplate(messageTemplate, event.getView().getParameters(), origin);
+                        }
+                    })
+                    .open();
+        } else {
+            showTemplate(messageTemplate, Collections.emptyMap(), origin);
+        }
+    }
+
+    /**
+     * Generates the message template using the provided parameters
+     * and displays the result in the preview dialog.
+     *
+     * @param template   the message template
+     * @param parameters parameters used for generation
+     * @param origin     the originating view
+     */
+    protected void showTemplate(MessageTemplate template, Map<String, Object> parameters, View<?> origin) {
+        String content = messageTemplatesGenerator.generateMessage(template, parameters);
+
+        dialogWindows.view(origin, MessageTemplatePreviewView.class)
+                .withViewConfigurer(view -> view.setPreviewContent(template.getType(), content))
+                .open();
+    }
+}

jmix-messagetemplates/messagetemplates-flowui/src/main/resources/io/jmix/messagetemplatesflowui/messages.properties

@@ -21,10 +21,12 @@ io.jmix.messagetemplatesflowui.view.messagetemplategroup/MessageTemplateGroupDet
 io.jmix.messagetemplatesflowui.view.messagetemplateblock/MessageTemplateBlockListView.title=Template blocks
 io.jmix.messagetemplatesflowui.view.messagetemplateblock/MessageTemplateBlockDetailView.title=Template block
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter/MessageTemplateParameterDetailView.title=Template parameter
+io.jmix.messagetemplatesflowui.view.messagetemplatepreview/MessageTemplatePreviewView.title=Preview
 io.jmix.messagetemplatesflowui.view.parametersinputdialog/MessageTemplateParametersInputDialog.title=Input parameters
 
 io.jmix.messagetemplatesflowui.view.messagetemplate/exportButton.text=Export
 io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.copyAction.text=Copy
+io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.previewAction.text=Preview
 io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.exportJsonAction.text=Export as JSON
 io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.exportZipAction.text=Export as ZIP
 io.jmix.messagetemplatesflowui.view.messagetemplate/importField.uploadText=Import
@@ -39,6 +41,7 @@ io.jmix.messagetemplatesflowui.view.messagetemplate/mainTabSheet.parametersTab.l
 io.jmix.messagetemplatesflowui.view.messagetemplate/importTemplateField.title=Import HTML
 io.jmix.messagetemplatesflowui.view.messagetemplate/editCodeBtn.title=Edit HTML
 io.jmix.messagetemplatesflowui.view.messagetemplate/viewBtn.title=View HTML
+io.jmix.messagetemplatesflowui.view.messagetemplate/previewButton.text=Preview
 io.jmix.messagetemplatesflowui.view.messagetemplate/plainTextArea.header=Template content
 io.jmix.messagetemplatesflowui.view.messagetemplate/emptyContentValidationMessage=Template content must not be blank
 
@@ -49,6 +52,8 @@ io.jmix.messagetemplatesflowui.view.messagetemplateparameter/mainTabSheet.detail
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter/mainTabSheet.localizationTab.label=Localization
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter/uniqueAliasValidationMessage=A parameter with the same alias already exist
 
+io.jmix.messagetemplatesflowui.view.messagetemplatepreview/openInNewTabButton.text=Open in new tab
+
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter.model/MessageTemplateParameterLocalization=Message template parameter localization
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter.model/MessageTemplateParameterLocalization.id=ID
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter.model/MessageTemplateParameterLocalization.locale=Locale

jmix-messagetemplates/messagetemplates-flowui/src/main/resources/io/jmix/messagetemplatesflowui/view/messagetemplate/message-template-detail-view.xml

@@ -77,8 +77,8 @@
                             <hbox id="htmlTemplateControlsPanel" classNames="buttons-panel">
                                 <fileUploadField id="importTemplateField" uploadIcon="UPLOAD"
                                                  acceptedFileTypes=".html"/>
+                                <button id="viewBtn" icon="DOWNLOAD" title="msg://viewBtn.title"/>
                                 <button id="editCodeBtn" icon="CODE" title="msg://editCodeBtn.title"/>
-                                <button id="viewBtn" icon="EYE" title="msg://viewBtn.title"/>
                             </hbox>
                             <msgtmp:grapesJs id="grapesJsEditor" width="100%"
                                              minHeight="20em">
@@ -132,6 +132,8 @@
         </tabSheet>
         <hbox id="detailActions">
             <button id="saveAndCloseButton" action="saveAction"/>
+            <button id="previewButton" icon="EYE"
+                    text="msg://previewButton.text"/>
             <button id="closeButton" action="closeAction"/>
         </hbox>
     </layout>

jmix-messagetemplates/messagetemplates-flowui/src/main/resources/io/jmix/messagetemplatesflowui/view/messagetemplate/message-template-list-view.xml

@@ -58,6 +58,7 @@
             <button id="editButton" action="messageTemplatesDataGrid.edit"/>
             <button id="removeButton" action="messageTemplatesDataGrid.remove"/>
             <button id="copyButton" action="messageTemplatesDataGrid.copy"/>
+            <button id="previewButton" action="messageTemplatesDataGrid.preview"/>
             <dropdownButton id="exportButton" text="msg://exportButton.text" icon="DOWNLOAD">
                 <items>
                     <actionItem id="exportJsonAction" ref="messageTemplatesDataGrid.exportJson"/>
@@ -79,6 +80,8 @@
                 <action id="remove" type="list_remove"/>
                 <action id="copy" type="list_itemTracking" icon="COPY"
                         text="msg://messageTemplatesDataGrid.copyAction.text"/>
+                <action id="preview" type="list_itemTracking" icon="EYE"
+                        text="msg://messageTemplatesDataGrid.previewAction.text"/>
                 <action id="exportJson" icon="FILE_CODE"
                         text="msg://messageTemplatesDataGrid.exportJsonAction.text"/>
                 <action id="exportZip" icon="FILE_ZIP"

jmix-messagetemplates/messagetemplates-flowui/src/main/resources/io/jmix/messagetemplatesflowui/view/messagetemplatepreview/message-template-preview-view.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+  ~ Copyright 2026 Haulmont.
+  ~
+  ~ 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.
+  -->
+<view xmlns="http://jmix.io/schema/flowui/view"
+      title="msg://MessageTemplatePreviewView.title">
+    <actions>
+        <action id="closeAction" type="view_close"/>
+    </actions>
+    <layout alignItems="STRETCH"
+            padding="false" spacing="false"
+            expand="contentBox">
+        <vbox id="contentBox"/>
+        <hbox id="actionsPanel"
+              classNames="footer-panel">
+            <button id="openInNewTabButton" icon="EXTERNAL_LINK" text="msg://openInNewTabButton.text" visible="false"/>
+            <button id="closeButton" action="closeAction"/>
+        </hbox>
+    </layout>
+</view>

jmix-translations/content/io/jmix/messagetemplatesflowui/messages.properties

@@ -21,10 +21,12 @@ io.jmix.messagetemplatesflowui.view.messagetemplategroup/MessageTemplateGroupDet
 io.jmix.messagetemplatesflowui.view.messagetemplateblock/MessageTemplateBlockListView.title=Template blocks
 io.jmix.messagetemplatesflowui.view.messagetemplateblock/MessageTemplateBlockDetailView.title=Template block
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter/MessageTemplateParameterDetailView.title=Template parameter
+io.jmix.messagetemplatesflowui.view.messagetemplatepreview/MessageTemplatePreviewView.title=Preview
 io.jmix.messagetemplatesflowui.view.parametersinputdialog/MessageTemplateParametersInputDialog.title=Input parameters
 
 io.jmix.messagetemplatesflowui.view.messagetemplate/exportButton.text=Export
 io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.copyAction.text=Copy
+io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.previewAction.text=Preview
 io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.exportJsonAction.text=Export as JSON
 io.jmix.messagetemplatesflowui.view.messagetemplate/messageTemplatesDataGrid.exportZipAction.text=Export as ZIP
 io.jmix.messagetemplatesflowui.view.messagetemplate/importField.uploadText=Import
@@ -39,6 +41,7 @@ io.jmix.messagetemplatesflowui.view.messagetemplate/mainTabSheet.parametersTab.l
 io.jmix.messagetemplatesflowui.view.messagetemplate/importTemplateField.title=Import HTML
 io.jmix.messagetemplatesflowui.view.messagetemplate/editCodeBtn.title=Edit HTML
 io.jmix.messagetemplatesflowui.view.messagetemplate/viewBtn.title=View HTML
+io.jmix.messagetemplatesflowui.view.messagetemplate/previewButton.text=Preview
 io.jmix.messagetemplatesflowui.view.messagetemplate/plainTextArea.header=Template content
 io.jmix.messagetemplatesflowui.view.messagetemplate/emptyContentValidationMessage=Template content must not be blank
 
@@ -49,6 +52,8 @@ io.jmix.messagetemplatesflowui.view.messagetemplateparameter/mainTabSheet.detail
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter/mainTabSheet.localizationTab.label=Localization
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter/uniqueAliasValidationMessage=A parameter with the same alias already exist
 
+io.jmix.messagetemplatesflowui.view.messagetemplatepreview/openInNewTabButton.text=Open in new tab
+
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter.model/MessageTemplateParameterLocalization=Message template parameter localization
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter.model/MessageTemplateParameterLocalization.id=ID
 io.jmix.messagetemplatesflowui.view.messagetemplateparameter.model/MessageTemplateParameterLocalization.locale=Locale