Start Boot LS if classpath of any project has spring

eclipse-language-servers/org.springframework.tooling.boot.ls/META-INF/MANIFEST.MF

@@ -35,7 +35,8 @@ Require-Bundle: org.eclipse.jdt.launching;bundle-version="3.9.0",
  org.springframework.ide.eclipse.editor.support,
  com.google.guava,
  org.eclipse.core.expressions,
- org.springsource.ide.eclipse.commons.core;bundle-version="4.17.0"
+ org.springsource.ide.eclipse.commons.core;bundle-version="4.17.0",
+ org.springframework.tooling.jdt.ls.commons;bundle-version="4.17.0"
 Import-Package: com.google.common.base,
  com.google.common.collect,
  com.google.gson;version="2.7.0",

eclipse-language-servers/org.springframework.tooling.boot.ls/plugin.xml

@@ -9,7 +9,7 @@
             clientImpl="org.springframework.tooling.ls.eclipse.commons.STS4LanguageClientImpl"
             id="org.eclipse.languageserver.languages.springboot"
             label="Spring Boot Language Server"
-            lastDocumentDisconnectedTimeout="10">
+            lastDocumentDisconnectedTimeout="2147483647">
       </server>
 
       <contentTypeMapping
@@ -494,6 +494,12 @@
             type="java.lang.Object">
       </propertyTester>
    </extension>
+   <extension
+         point="org.eclipse.ui.startup">
+      <startup
+            class="org.springframework.tooling.boot.ls.Startup">
+      </startup>
+   </extension>
 <!--
    <extension
          point="org.eclipse.wildwebdeveloper.xml.lemminxExtension">

eclipse-language-servers/org.springframework.tooling.boot.ls/src/org/springframework/tooling/boot/ls/Startup.java

@@ -0,0 +1,115 @@
+/*******************************************************************************
+ * Copyright (c) 2022 VMware, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VMware, Inc. - initial API and implementation
+ *******************************************************************************/
+package org.springframework.tooling.boot.ls;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.IPath;
+import org.eclipse.jdt.core.IClasspathEntry;
+import org.eclipse.jdt.core.IJavaProject;
+import org.eclipse.jdt.core.JavaCore;
+import org.eclipse.jdt.core.JavaModelException;
+import org.eclipse.lsp4e.LanguageServerWrapper;
+import org.eclipse.lsp4e.LanguageServersRegistry;
+import org.eclipse.lsp4e.LanguageServiceAccessor;
+import org.eclipse.ui.IStartup;
+import org.springframework.tooling.jdt.ls.commons.Logger;
+import org.springframework.tooling.jdt.ls.commons.classpath.ClasspathListenerManager;
+
+@SuppressWarnings("restriction")
+public class Startup implements IStartup {
+	
+	private static final String BOOT_LS_DEFINITION_ID = "org.eclipse.languageserver.languages.springboot";
+	
+	private Set<IJavaProject> springProjects = new HashSet<>();
+	private LanguageServerWrapper lsWrapper = null;
+
+	@Override
+	public void earlyStartup() {
+		new ClasspathListenerManager(Logger.forEclipsePlugin(() -> BootLanguageServerPlugin.getDefault()), new ClasspathListenerManager.ClasspathListener() {
+			
+			@Override
+			public void classpathChanged(IJavaProject jp) {
+				processProject(jp);
+			}
+		});
+		for (IProject p : ResourcesPlugin.getWorkspace().getRoot().getProjects()) {
+			if (p != null && p.isAccessible()) {
+				IJavaProject jp = JavaCore.create(p);
+				if (jp != null && jp.exists()) {
+					processProject(jp);
+				}
+			}
+		}
+	}
+	
+	private void processProject(IJavaProject jp) {
+		if (isSpringProject(jp)) {
+			springProjects.add(jp);
+		} else {
+			springProjects.remove(jp);
+		}
+		if (springProjects.isEmpty()) {
+			if (lsWrapper != null) {
+				lsWrapper.stop();
+				lsWrapper = null;
+			}
+		} else {
+			if (lsWrapper == null) {
+				try {
+					lsWrapper = LanguageServiceAccessor.startLanguageServer(LanguageServersRegistry.getInstance().getDefinition(BOOT_LS_DEFINITION_ID));
+				} catch (IOException e) {
+					BootLanguageServerPlugin.getDefault().getLog().error("Failed to launch Boot Language Server for " + jp.getElementName(), e);
+				}
+
+			}
+		}
+	}
+	
+	private boolean isSpringProject(IJavaProject jp) {
+		try {
+			IClasspathEntry[] classpath = jp.getResolvedClasspath(true);
+			//Look for a 'spring-core' jar or project entry
+			for (IClasspathEntry e : classpath) {
+				if (isBootJar(e) || isBootProject(e)) {
+					return true;
+				}
+			}
+		} catch (JavaModelException e) {
+			BootLanguageServerPlugin.getDefault().getLog().error("Cannot compute classpath for project " + jp.getElementName(), e);
+		}
+		return false;
+	}
+	
+	public static boolean isBootProject(IClasspathEntry e) {
+		if (e.getEntryKind()==IClasspathEntry.CPE_PROJECT) {
+			IPath path = e.getPath();
+			String name = path.lastSegment();
+			return name.startsWith("spring-core");
+		}
+		return false;
+	}
+
+	public static boolean isBootJar(IClasspathEntry e) {
+		if (e.getEntryKind()==IClasspathEntry.CPE_LIBRARY) {
+			IPath path = e.getPath();
+			String name = path.lastSegment();
+			return name.endsWith(".jar") && name.startsWith("spring-core");
+		}
+		return false;
+	}
+
+
+}