Add ComboBox custom filtering methods and tests

Change-Id: I640c6a7b3b8b89eff4b007d1cb70a25bbe28167e

server/src/main/java/com/vaadin/server/SerializableBiPredicate.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * 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.vaadin.server;
+
+import java.io.Serializable;
+import java.util.function.BiPredicate;
+
+/**
+ * A {@link BiPredicate} that is also {@link Serializable}.
+ *
+ * @author Vaadin Ltd
+ * @since 8.0
+ * @param <T>
+ *            the type of the first input to the predicate
+ * @param <U>
+ *            the type of the second input to the predicate
+ */
+public interface SerializableBiPredicate<T, U>
+        extends BiPredicate<T, U>, Serializable {
+    // Only method inherited from Function
+}

server/src/main/java/com/vaadin/ui/ComboBox.java

@@ -39,6 +39,7 @@ import com.vaadin.event.FieldEvents.FocusListener;
 import com.vaadin.server.KeyMapper;
 import com.vaadin.server.Resource;
 import com.vaadin.server.ResourceReference;
+import com.vaadin.server.SerializableBiPredicate;
 import com.vaadin.server.data.DataCommunicator;
 import com.vaadin.server.data.DataKeyMapper;
 import com.vaadin.server.data.DataProvider;
@@ -254,6 +255,50 @@ public class ComboBox<T> extends AbstractSingleSelect<T>
         setDataProvider(provider);
     }
 
+    /**
+     * Sets the data items of this listing and a simple string filter with which
+     * the item string and the text the user has input are compared.
+     * <p>
+     * Note that unlike {@link #setItems(Collection)}, no automatic case
+     * conversion is performed before the comparison.
+     *
+     * @param filterPredicate
+     *            predicate for comparing the item string (first parameter) and
+     *            the filter string (second parameter)
+     * @param items
+     *            the data items to display
+     */
+    public void setItems(
+            SerializableBiPredicate<String, String> filterPredicate,
+            Collection<T> items) {
+        DataProvider<T, String> provider = DataProvider.create(items)
+                .convertFilter(filterText -> item -> filterPredicate.test(
+                        getItemCaptionGenerator().apply(item), filterText));
+        setDataProvider(provider);
+    }
+
+    /**
+     * Sets the data items of this listing and a simple string filter with which
+     * the item string and the text the user has input are compared.
+     * <p>
+     * Note that unlike {@link #setItems(Collection)}, no automatic case
+     * conversion is performed before the comparison.
+     *
+     * @param filterPredicate
+     *            predicate for comparing the item string (first parameter) and
+     *            the filter string (second parameter)
+     * @param items
+     *            the data items to display
+     */
+    public void setItems(
+            SerializableBiPredicate<String, String> filterPredicate,
+            @SuppressWarnings("unchecked") T... items) {
+        DataProvider<T, String> provider = DataProvider.create(items)
+                .convertFilter(filterText -> item -> filterPredicate.test(
+                        getItemCaptionGenerator().apply(item), filterText));
+        setDataProvider(provider);
+    }
+
     /**
      * Gets the current placeholder text shown when the combo box would be
      * empty.

server/src/test/java/com/vaadin/tests/server/component/combobox/ComboBoxFilteringTest.java

@@ -0,0 +1,181 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * 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.vaadin.tests.server.component.combobox;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.vaadin.server.data.DataProvider;
+import com.vaadin.server.data.ListDataProvider;
+import com.vaadin.server.data.Query;
+import com.vaadin.tests.data.bean.Person;
+import com.vaadin.tests.data.bean.Sex;
+import com.vaadin.ui.ComboBox;
+
+/**
+ * Test for ComboBox data providers and filtering.
+ *
+ * @author Vaadin Ltd
+ */
+public class ComboBoxFilteringTest {
+    private static final String[] PERSON_NAMES = new String[] {
+            "Enrique Iglesias", "Henry Dunant", "Erwin Engelbrecht" };
+
+    private ComboBox<Person> comboBox;
+
+    @Before
+    public void setup() {
+        comboBox = new ComboBox<>();
+        comboBox.setLocale(Locale.US);
+    }
+
+    @Test
+    public void setItems_array_defaultFiltering() {
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        // Result: typing "en" into the search field finds "Enrique Iglesias"
+        // and "Henry Dunant", but not "Erwin Engelbrecht"
+        comboBox.setItems(getPersonArray());
+
+        checkFiltering("en", "ennen", 3, 2);
+    }
+
+    @Test
+    public void setItems_array_setItemCaptionAfterItems() {
+        // Result: typing "en" into the search field finds "Enrique Iglesias"
+        // and "Henry Dunant", but not "Erwin Engelbrecht"
+        comboBox.setItems(getPersonArray());
+
+        // It shouldn't matter if this is done before or after setItems
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        checkFiltering("en", "ennen", 3, 2);
+    }
+
+    @Test
+    public void setItems_collection_defaultFiltering() {
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        // Result: typing "en" into the search field finds "Enrique Iglesias"
+        // and "Henry Dunant", but not "Erwin Engelbrecht"
+        comboBox.setItems(getPersonCollection());
+
+        checkFiltering("en", "ennen", 3, 2);
+    }
+
+    @Test
+    public void setItems_collection_setItemCaptionAfterItems() {
+        // Result: typing "en" into the search field finds "Enrique Iglesias"
+        // and "Henry Dunant", but not "Erwin Engelbrecht"
+        comboBox.setItems(getPersonCollection());
+
+        // It shouldn't matter if this is done before or after setItems
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        checkFiltering("en", "ennen", 3, 2);
+    }
+
+    @Test
+    public void setItems_array_customFiltering() {
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        // Result: typing "en" into the search field finds "Enrique Iglesias"
+        // and "Henry Dunant", but not "Erwin Engelbrecht"
+        comboBox.setItems(String::startsWith, getPersonArray());
+
+        checkFiltering("Er", "er", 3, 1);
+    }
+
+    @Test
+    public void setItems_collection_customFiltering() {
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        // Result: typing "en" into the search field finds "Enrique Iglesias"
+        // and "Henry Dunant", but not "Erwin Engelbrecht"
+        comboBox.setItems(String::startsWith, getPersonCollection());
+
+        checkFiltering("Er", "er", 3, 1);
+    }
+
+    public void invalid_dataProvider_compile_error() {
+        // uncommenting this causes a compile time error
+        ListDataProvider<Person> ldp = DataProvider.create(getPersonArray());
+        // Compile error, because of invalid data provider filter type
+        // comboBox.setDataProvider(ldp);
+    }
+
+    @Test
+    public void customDataProvider_filterByLastName() {
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        // Filters by last name, regardless of the item caption generator
+        ListDataProvider<Person> ldp = DataProvider.create(getPersonArray());
+        comboBox.setDataProvider(ldp.convertFilter(
+                text -> person -> person.getLastName().contains(text)));
+
+        checkFiltering("u", "ab", 3, 1);
+    }
+
+    @Test
+    public void customDataProvider_filterByLastNameWithAccessRestriction() {
+        comboBox.setItemCaptionGenerator(Person::getFirstName);
+
+        // Filters by last name, regardless of the item caption generator
+        ListDataProvider<Person> ldp = DataProvider.create(getPersonArray());
+        // Same as above, but only showing a subset of the persons
+        comboBox.setDataProvider(ldp
+                .applyFilter(person -> person.getFirstName().contains("nr"))
+                .convertFilter(
+                        text -> person -> person.getLastName().contains(text)));
+
+        checkFiltering("t", "Engel", 2, 1);
+    }
+
+    private void checkFiltering(String filterText, String nonMatchingFilterText,
+            int totalMatches, int matchingResults) {
+        DataProvider<Person, String> dataProvider = comboBox.getDataProvider();
+
+        Assert.assertEquals(
+                "ComboBox filtered out results with no filter applied",
+                totalMatches, dataProvider.size(new Query<String>()));
+        Assert.assertEquals(
+                "ComboBox filtered out results with empty filter string",
+                totalMatches, dataProvider.size(new Query<String>("")));
+        Assert.assertEquals("ComboBox filtered out wrong number of results",
+                matchingResults,
+                dataProvider.size(new Query<String>(filterText)));
+        Assert.assertEquals(
+                "ComboBox should have no results with a non-matching filter", 0,
+                dataProvider.size(new Query<String>(nonMatchingFilterText)));
+    }
+
+    private List<Person> getPersonCollection() {
+        return Stream
+                .of(PERSON_NAMES).map(name -> new Person(name.split(" ")[0],
+                        name.split(" ")[1], null, 0, Sex.MALE, null))
+                .collect(Collectors.toList());
+    }
+
+    private Person[] getPersonArray() {
+        return getPersonCollection().toArray(new Person[PERSON_NAMES.length]);
+    }
+}