Fix eclipse-jdtls#3252 Add support for scoping the search operations

The current version support scoping the following search operations
- reference search
- call hierarchy search

with the following scopes to choose from
- all : includes all classpath entries
- main: all classpath entries excluding test

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/ReferencesHandler.java

@@ -45,6 +45,7 @@
 import org.eclipse.jdt.ls.core.internal.JDTUtils;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
 import org.eclipse.jdt.ls.core.internal.preferences.PreferenceManager;
+import org.eclipse.jdt.ls.core.internal.preferences.Preferences.SearchScope;
 import org.eclipse.lsp4j.Location;
 import org.eclipse.lsp4j.ReferenceParams;
 
@@ -62,7 +63,8 @@ private IJavaSearchScope createSearchScope(IJavaElement elementToSearch) throws
 		if (isInsideJRE(elementToSearch)) {
 			includeMask |= IJavaSearchScope.SYSTEM_LIBRARIES;
 		}
-		return SearchEngine.createJavaSearchScope(projects, includeMask);
+		var excludeTestCode = preferenceManager.getPreferences().getSearchScope() == SearchScope.main;
+		return SearchEngine.createJavaSearchScope(excludeTestCode, projects, includeMask);
 	}
 
 	public List<Location> findReferences(ReferenceParams param, IProgressMonitor monitor) {

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/preferences/PreferenceManager.java

@@ -57,6 +57,7 @@
 import org.eclipse.jdt.ls.core.internal.StatusFactory;
 import org.eclipse.jdt.ls.core.internal.handlers.BaseDiagnosticsHandler;
 import org.eclipse.jdt.ls.core.internal.handlers.FormatterHandler;
+import org.eclipse.jdt.ls.core.internal.preferences.Preferences.SearchScope;
 import org.eclipse.jface.text.templates.Template;
 import org.eclipse.jface.text.templates.TemplateContextType;
 import org.eclipse.lsp4j.ClientCapabilities;
@@ -259,6 +260,10 @@ public void update(Preferences preferences) {
 		if (!oldPreferences.getFilesAssociations().equals(preferences.getFilesAssociations())) {
 			configureContentTypes(preferences);
 		}
+
+		// update call hierachy test code filer
+		final boolean filterTestCode = this.preferences.getSearchScope() == SearchScope.main;
+		eclipsePreferences.put("PREF_FILTER_TESTCODE", String.valueOf(filterTestCode));
 	}
 
 	// only for test purpose

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/preferences/Preferences.java

@@ -537,6 +537,16 @@ public class Preferences {
 	 */
 	public static final String CHAIN_COMPLETION_KEY = "java.completion.chain.enabled";
 
+	/**
+	 * Preference key to set the scope value to use when searching java code. Allowed value are
+	 * <ul>
+	 * <li><code>main</code>			-	Scope for main code</li>
+	 * <li><code>all</code>				-	Scope for both test and main code</li>
+	 * </ul>
+	 * Any other unknown value will be treated as <code>all</code>.
+	 */
+	public static final String JAVA_SEARCH_SCOPE = "java.search.scope";
+
 	public static final String TEXT_DOCUMENT_FORMATTING = "textDocument/formatting";
 	public static final String TEXT_DOCUMENT_RANGE_FORMATTING = "textDocument/rangeFormatting";
 	public static final String TEXT_DOCUMENT_ON_TYPE_FORMATTING = "textDocument/onTypeFormatting";
@@ -704,6 +714,7 @@ public class Preferences {
 	private boolean validateAllOpenBuffersOnChanges;
 	private boolean chainCompletionEnabled;
 	private List<String> diagnosticFilter;
+	private SearchScope searchScope;
 
 	static {
 		JAVA_IMPORT_EXCLUSIONS_DEFAULT = new LinkedList<>();
@@ -781,6 +792,22 @@ static FeatureStatus fromString(String value, FeatureStatus defaultStatus) {
 		}
 	}
 
+	public static enum SearchScope {
+		all, main;
+
+		static SearchScope fromString(String value, SearchScope defaultScope) {
+			if (value != null) {
+				String val = value.toLowerCase();
+				try {
+					return valueOf(val);
+				} catch(Exception e) {
+					//fall back to default severity
+				}
+			}
+			return defaultScope;
+		}
+	}
+
 	public static class ReferencedLibraries {
 		private Set<String> include;
 		private Set<String> exclude;
@@ -1352,6 +1379,10 @@ public static Preferences createFrom(Map<String, Object> configuration) {
 			}
 		}
 		prefs.setFilesAssociations(new ArrayList<>(associations));
+
+		String searchScope = getString(configuration, JAVA_SEARCH_SCOPE, null);
+		prefs.setSearchScope(SearchScope.fromString(searchScope, SearchScope.all));
+
 		return prefs;
 	}
 
@@ -2623,4 +2654,12 @@ public List<String> getFilesAssociations() {
 	public void setFilesAssociations(List<String> filesAssociations) {
 		this.filesAssociations = filesAssociations;
 	}
+
+	public void setSearchScope(SearchScope value) {
+		this.searchScope = value;
+	}
+
+	public SearchScope getSearchScope() {
+		return searchScope;
+	}
 }