Sort completion by relevance & respect completion filters registered by JLS (microsoft#359)

* Sort completion by relevance & respect completion filters registered by JLS

* Make checkstyle happy

Author: testforstephen

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/protocol/Types.java

@@ -278,6 +278,10 @@ public static class CompletionItem {
         public String label;
         public String text;
         public String type;
+        /**
+         * A string that should be used when comparing this item with other items.
+         */
+        public String sortText;
 
         public int start;
         public int number;

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/CompletionProposalRequestor.java

@@ -22,6 +22,7 @@
 import java.util.logging.Logger;
 
 import org.apache.commons.lang3.StringUtils;
+import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.jdt.core.CompletionContext;
@@ -34,6 +35,7 @@
 import org.eclipse.jdt.core.IType;
 import org.eclipse.jdt.core.ITypeRoot;
 import org.eclipse.jdt.core.JavaModelException;
+import org.eclipse.jdt.core.Signature;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
 import org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalDescriptionProvider;
 import org.eclipse.jdt.ls.core.internal.contentassist.GetterSetterCompletionProposal;
@@ -109,6 +111,10 @@ private boolean isTestSource(IJavaProject project, ITypeRoot cu) {
 
     @Override
     public void accept(CompletionProposal proposal) {
+        if (isFiltered(proposal)) {
+            return;
+        }
+
         if (!isIgnored(proposal.getKind())) {
             if (proposal.getKind() == CompletionProposal.POTENTIAL_METHOD_DECLARATION) {
                 acceptPotentialMethodDeclaration(proposal);
@@ -265,4 +271,81 @@ public CompletionContext getContext() {
         return context;
     }
 
-}
+    /**
+     * copied from
+     * org.eclipse.jdt.ui.text.java.CompletionProposalCollector.isFiltered(CompletionProposal)
+     */
+    private boolean isFiltered(CompletionProposal proposal) {
+        if (isIgnored(proposal.getKind())) {
+            return true;
+        }
+
+        try {
+            // Only filter types and constructors from completion.
+            // Methods from already imported types and packages can still be proposed.
+            // See https://github.com/eclipse/eclipse.jdt.ls/issues/1212
+            switch (proposal.getKind()) {
+                case CompletionProposal.CONSTRUCTOR_INVOCATION:
+                case CompletionProposal.ANONYMOUS_CLASS_CONSTRUCTOR_INVOCATION:
+                case CompletionProposal.JAVADOC_TYPE_REF:
+                case CompletionProposal.TYPE_REF: {
+                    char[] declaringType = getDeclaringType(proposal);
+                    return declaringType != null && org.eclipse.jdt.ls.core.internal.contentassist.TypeFilter.isFiltered(declaringType);
+                }
+                default: // do nothing
+            }
+        } catch (Exception e) {
+            // do nothing
+        }
+
+        return false;
+    }
+
+    /**
+     * copied from
+     * org.eclipse.jdt.ui.text.java.CompletionProposalCollector.getDeclaringType(CompletionProposal)
+     */
+    private final char[] getDeclaringType(CompletionProposal proposal) {
+        switch (proposal.getKind()) {
+            case CompletionProposal.METHOD_DECLARATION:
+            case CompletionProposal.METHOD_NAME_REFERENCE:
+            case CompletionProposal.JAVADOC_METHOD_REF:
+            case CompletionProposal.METHOD_REF:
+            case CompletionProposal.CONSTRUCTOR_INVOCATION:
+            case CompletionProposal.ANONYMOUS_CLASS_CONSTRUCTOR_INVOCATION:
+            case CompletionProposal.METHOD_REF_WITH_CASTED_RECEIVER:
+            case CompletionProposal.ANNOTATION_ATTRIBUTE_REF:
+            case CompletionProposal.POTENTIAL_METHOD_DECLARATION:
+            case CompletionProposal.ANONYMOUS_CLASS_DECLARATION:
+            case CompletionProposal.FIELD_REF:
+            case CompletionProposal.FIELD_REF_WITH_CASTED_RECEIVER:
+            case CompletionProposal.JAVADOC_FIELD_REF:
+            case CompletionProposal.JAVADOC_VALUE_REF:
+                char[] declaration = proposal.getDeclarationSignature();
+                // special methods may not have a declaring type: methods defined on arrays etc.
+                // Currently known: class literals don't have a declaring type - use Object
+                if (declaration == null) {
+                    return "java.lang.Object".toCharArray(); //$NON-NLS-1$
+                }
+                return Signature.toCharArray(declaration);
+            case CompletionProposal.PACKAGE_REF:
+            case CompletionProposal.MODULE_REF:
+            case CompletionProposal.MODULE_DECLARATION:
+                return proposal.getDeclarationSignature();
+            case CompletionProposal.JAVADOC_TYPE_REF:
+            case CompletionProposal.TYPE_REF:
+                return Signature.toCharArray(proposal.getSignature());
+            case CompletionProposal.LOCAL_VARIABLE_REF:
+            case CompletionProposal.VARIABLE_DECLARATION:
+            case CompletionProposal.KEYWORD:
+            case CompletionProposal.LABEL_REF:
+            case CompletionProposal.JAVADOC_BLOCK_TAG:
+            case CompletionProposal.JAVADOC_INLINE_TAG:
+            case CompletionProposal.JAVADOC_PARAM_REF:
+                return null;
+            default:
+                Assert.isTrue(false);
+                return null;
+        }
+    }
+}

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/CompletionsProvider.java

@@ -115,6 +115,11 @@ private CompletionItem convertFromLsp(org.eclipse.lsp4j.CompletionItem lspItem)
         if (lspItem.getKind() != null) {
             item.type = lspItem.getKind().name().toLowerCase();
         }
+
+        if (lspItem.getSortText() != null) {
+            item.sortText = lspItem.getSortText();
+        }
+
         return item;
     }
 }