Implement GroupSuggestOracle

This cl implemented a SuggestOracle for group suggestion API implemented
in Ia1cfa068246127c29f1b74f6aa4562a9167c301e under gerrit-plugin-gwtui,
so that plugins can use this SuggestOracle to do group auto completion
in the UI (in combine with a SuggestBox).

It also implemented HighlightSuggestion under gerrit-gwtui-common.

Change-Id: I76a6d1c5c181a7bd083eb28f49fa9ffa1b7759f5

gerrit-gwtui-common/BUCK

@@ -64,6 +64,7 @@ java_test(
   deps = [
     ':client',
     '//lib:junit',
+    '//lib/gwt:user',
     '//lib/jgit:jgit',
   ],
   source_under_test = [':client'],

gerrit-gwtui-common/src/main/java/com/google/gerrit/client/ui/HighlightSuggestion.java

@@ -0,0 +1,55 @@
+// Copyright (C) 2015 The Android Open Source Project
+//
+// 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 com.google.gerrit.client.ui;
+
+import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
+import com.google.gwt.user.client.ui.SuggestOracle.Suggestion;
+
+/** A {@code Suggestion} with highlights. */
+public class HighlightSuggestion implements Suggestion {
+
+  private final String keyword;
+  private final String value;
+
+  public HighlightSuggestion(String keyword, String value) {
+    this.keyword = keyword;
+    this.value = value;
+  }
+
+  @Override
+  public String getDisplayString() {
+    int start = 0;
+    int keyLen = keyword.length();
+    SafeHtmlBuilder builder = new SafeHtmlBuilder();
+    for (;;) {
+      int index = value.indexOf(keyword, start);
+      if (index == -1) {
+        builder.appendEscaped(value.substring(start));
+        break;
+      }
+      builder.appendEscaped(value.substring(start, index));
+      builder.appendHtmlConstant("<strong>");
+      start = index + keyLen;
+      builder.appendEscaped(value.substring(index, start));
+      builder.appendHtmlConstant("</strong>");
+    }
+    return builder.toSafeHtml().asString();
+  }
+
+  @Override
+  public String getReplacementString() {
+    return value;
+  }
+}

gerrit-gwtui-common/src/test/java/com/google/gerrit/client/ui/HighlightSuggestionTest.java

@@ -0,0 +1,53 @@
+// Copyright (C) 2015 The Android Open Source Project
+//
+// 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 com.google.gerrit.client.ui;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class HighlightSuggestionTest {
+
+  @Test
+  public void singleHighlight() throws Exception {
+    String keyword = "key";
+    String value = "somethingkeysomething";
+    HighlightSuggestion suggestion = new HighlightSuggestion(keyword, value);
+    assertEquals(
+        "something<strong>key</strong>something",
+        suggestion.getDisplayString());
+    assertEquals(value, suggestion.getReplacementString());
+  }
+
+  @Test
+  public void noHighlight() throws Exception {
+    String keyword = "key";
+    String value = "something";
+    HighlightSuggestion suggestion = new HighlightSuggestion(keyword, value);
+    assertEquals(value, suggestion.getDisplayString());
+    assertEquals(value, suggestion.getReplacementString());
+  }
+
+  @Test
+  public void doubleHighlight() throws Exception {
+    String keyword = "key";
+    String value = "somethingkeysomethingkeysomething";
+    HighlightSuggestion suggestion = new HighlightSuggestion(keyword, value);
+    assertEquals(
+        "something<strong>key</strong>something<strong>key</strong>something",
+        suggestion.getDisplayString());
+    assertEquals(value, suggestion.getReplacementString());
+  }
+}

gerrit-plugin-gwtui/src/main/java/com/google/gerrit/plugin/client/ui/GroupSuggestOracle.java

@@ -0,0 +1,84 @@
+// Copyright (C) 2015 The Android Open Source Project
+//
+// 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 com.google.gerrit.plugin.client.ui;
+
+import com.google.gerrit.client.rpc.NativeMap;
+import com.google.gerrit.client.ui.HighlightSuggestion;
+import com.google.gerrit.plugin.client.rpc.RestApi;
+import com.google.gwt.core.client.JavaScriptObject;
+import com.google.gwt.user.client.rpc.AsyncCallback;
+import com.google.gwt.user.client.ui.SuggestOracle;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/** A {@code SuggestOracle} for groups. */
+public class GroupSuggestOracle extends SuggestOracle {
+
+  private final int chars;
+
+  /**
+   * @param chars minimum chars to start suggesting.
+   */
+  public GroupSuggestOracle(int chars) {
+    this.chars = chars;
+  }
+
+  @Override
+  public boolean isDisplayStringHTML() {
+    return true;
+  }
+
+  @Override
+  public void requestSuggestions(final Request req, final Callback done) {
+    if (req.getQuery().length() < chars) {
+      responseEmptySuggestion(req, done);
+      return;
+    }
+    RestApi rest = new RestApi("/groups/").addParameter("suggest", req.getQuery());
+    if (req.getLimit() > 0) {
+      rest.addParameter("n", req.getLimit());
+    }
+    rest.get(new AsyncCallback<NativeMap<GroupInfo>>() {
+      @Override
+      public void onSuccess(NativeMap<GroupInfo> result) {
+        List<String> keys = result.sortedKeys();
+        List<Suggestion> suggestions = new ArrayList<>(keys.size());
+        for (String g : keys) {
+          suggestions.add(new HighlightSuggestion(req.getQuery(), g));
+        }
+        done.onSuggestionsReady(req, new Response(suggestions));
+      }
+
+      @Override
+      public void onFailure(Throwable caught) {
+        responseEmptySuggestion(req, done);
+      }
+    });
+  }
+
+  private static void responseEmptySuggestion(Request req, Callback done) {
+    List<Suggestion> empty = Collections.emptyList();
+    done.onSuggestionsReady(req, new Response(empty));
+  }
+
+  private static class GroupInfo extends JavaScriptObject {
+    // Dummy class, does nothing.
+
+    protected GroupInfo() {
+    }
+  }
+}