feat: add read-only Diagram tab for struts.xml config visualization

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Add read-only Diagram tab for struts.xml files with lightweight config visualization (packages, actions, results)
+
 ### Changed
 
 - Disable the deprecated Graph editor tab by default; opt in with JVM property `-Dcom.intellij.struts2.enableGraphEditor=true`

src/main/java/com/intellij/struts2/diagram/fileEditor/Struts2DiagramFileEditor.java

@@ -0,0 +1,108 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * 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.
+ */
+package com.intellij.struts2.diagram.fileEditor;
+
+import com.intellij.openapi.application.ReadAction;
+import com.intellij.openapi.progress.ProgressManager;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.xml.XmlFile;
+import com.intellij.struts2.diagram.model.StrutsConfigDiagramModel;
+import com.intellij.struts2.diagram.ui.Struts2DiagramComponent;
+import com.intellij.util.xml.DomElement;
+import com.intellij.util.xml.ui.PerspectiveFileEditor;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+
+/**
+ * Read-only file editor that hosts the lightweight Struts config diagram.
+ * <p>
+ * Both initial creation and {@link #reset()} go through the same
+ * {@link #buildModel()} path so the component always reflects the
+ * current model state &mdash; including explicit empty and unavailable
+ * fallbacks instead of stale or blank content.
+ */
+public class Struts2DiagramFileEditor extends PerspectiveFileEditor {
+
+    private final XmlFile myXmlFile;
+    private Struts2DiagramComponent myComponent;
+
+    public Struts2DiagramFileEditor(final Project project, final VirtualFile file) {
+        super(project, file);
+
+        final PsiFile psiFile = getPsiFile();
+        assert psiFile instanceof XmlFile;
+        myXmlFile = (XmlFile) psiFile;
+    }
+
+    @Override
+    @Nullable
+    protected DomElement getSelectedDomElement() {
+        return null;
+    }
+
+    @Override
+    protected void setSelectedDomElement(final DomElement domElement) {
+    }
+
+    @Override
+    @NotNull
+    protected JComponent createCustomComponent() {
+        return getDiagramComponent();
+    }
+
+    @Override
+    @Nullable
+    public JComponent getPreferredFocusedComponent() {
+        return getDiagramComponent();
+    }
+
+    @Override
+    public void commit() {
+    }
+
+    @Override
+    public void reset() {
+        getDiagramComponent().rebuild(buildModel());
+    }
+
+    @Override
+    @NotNull
+    public String getName() {
+        return "Diagram";
+    }
+
+    private @Nullable StrutsConfigDiagramModel buildModel() {
+        final StrutsConfigDiagramModel[] model = {null};
+        ProgressManager.getInstance().runProcessWithProgressSynchronously(
+                () -> model[0] = ReadAction.nonBlocking(
+                        () -> StrutsConfigDiagramModel.build(myXmlFile))
+                        .executeSynchronously(),
+                "Building Diagram", false, myXmlFile.getProject());
+        return model[0];
+    }
+
+    private Struts2DiagramComponent getDiagramComponent() {
+        if (myComponent == null) {
+            myComponent = new Struts2DiagramComponent(buildModel());
+        }
+        return myComponent;
+    }
+}

src/main/java/com/intellij/struts2/diagram/fileEditor/Struts2DiagramFileEditorProvider.java

@@ -0,0 +1,92 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * 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.
+ */
+package com.intellij.struts2.diagram.fileEditor;
+
+import com.intellij.openapi.module.Module;
+import com.intellij.openapi.module.ModuleUtilCore;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.PsiManager;
+import com.intellij.psi.jsp.JspFile;
+import com.intellij.psi.xml.XmlFile;
+import com.intellij.struts2.dom.struts.model.StrutsManager;
+import com.intellij.struts2.facet.ui.StrutsFileSet;
+import com.intellij.util.xml.ui.PerspectiveFileEditor;
+import com.intellij.util.xml.ui.PerspectiveFileEditorProvider;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Set;
+
+/**
+ * Provides the read-only "Diagram" tab for struts.xml files registered in a Struts file set.
+ * Uses the same eligibility rules as the legacy Graph tab but does not depend on
+ * deprecated {@code GraphBuilder} APIs.
+ */
+public class Struts2DiagramFileEditorProvider extends PerspectiveFileEditorProvider {
+
+    @Override
+    public boolean accept(@NotNull final Project project, @NotNull final VirtualFile file) {
+        if (!file.isValid()) {
+            return false;
+        }
+
+        final PsiFile psiFile = PsiManager.getInstance(project).findFile(file);
+
+        if (!(psiFile instanceof XmlFile)) {
+            return false;
+        }
+
+        if (psiFile instanceof JspFile) {
+            return false;
+        }
+
+        if (!StrutsManager.getInstance(project).isStruts2ConfigFile((XmlFile) psiFile)) {
+            return false;
+        }
+
+        final Module module = ModuleUtilCore.findModuleForFile(file, project);
+        if (module == null) {
+            return false;
+        }
+
+        final Set<StrutsFileSet> fileSets = StrutsManager.getInstance(project).getAllConfigFileSets(module);
+        for (final StrutsFileSet fileSet : fileSets) {
+            if (fileSet.hasFile(file)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    @Override
+    @NotNull
+    public PerspectiveFileEditor createEditor(@NotNull final Project project, @NotNull final VirtualFile file) {
+        return new Struts2DiagramFileEditor(project, file);
+    }
+
+    @Override
+    public boolean isDumbAware() {
+        return false;
+    }
+
+    @Override
+    public double getWeight() {
+        return 0;
+    }
+}