Optimize layout performance of Table (#17947)

Adds functions for skipping child component layout measuring.
Removes unnecessary code from VScrollTable.

1. case: no components

- render time without the fix: ~105ms 
- render time with fix: ~105ms 

2. case: 2 button and 2 textfield cols

- render time without the fix: ~279ms 
- render time with fix: ~240ms (~17% faster) 

3. case: 3 button and 3 textfield cols

- render time without the fix: ~350ms 
- render time with fix: ~281ms (~20% faster) 

Change-Id: I6025f8ee2fd438d228ff3b65f43535961cf12c0b

2 files changed, 229 insertions, 0 deletions

diff --git a/uitest/src/com/vaadin/tests/components/table/TableChildMeasurementHint.java b/uitest/src/com/vaadin/tests/components/table/TableChildMeasurementHint.java
new file mode 100644
index 0000000000..dd5d162e17
--- /dev/null
+++ b/uitest/src/com/vaadin/tests/components/table/TableChildMeasurementHint.java
@@ -0,0 +1,184 @@
+package com.vaadin.tests.components.table;
+
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.AbstractOrderedLayout;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.Button.ClickEvent;
+import com.vaadin.ui.Button.ClickListener;
+import com.vaadin.ui.ComboBox;
+import com.vaadin.ui.DateField;
+import com.vaadin.ui.GridLayout;
+import com.vaadin.ui.HasChildMeasurementHint.ChildMeasurementHint;
+import com.vaadin.ui.HorizontalLayout;
+import com.vaadin.ui.Label;
+import com.vaadin.ui.Table;
+import com.vaadin.ui.TextField;
+
+public class TableChildMeasurementHint extends AbstractTestUI {
+
+    private HorizontalLayout buttonLayout = new HorizontalLayout();
+    private HorizontalLayout layout;
+    private Table table1, table2, table3;
+
+    @Override
+    public void setup(VaadinRequest request) {
+        initMain();
+    }
+
+    protected void initMain() {
+        ((AbstractOrderedLayout) getContent()).setMargin(false);
+        layout = new HorizontalLayout();
+        layout.setSpacing(true);
+        layout.setMargin(false);
+        layout.setSizeFull();
+        addComponent(buttonLayout);
+        addComponent(layout);
+
+        table1 = createTable();
+        table1.setSizeFull();
+        table1.setChildMeasurementHint(ChildMeasurementHint.MEASURE_ALWAYS);
+
+        table2 = createTable();
+        table2.setSizeFull();
+        table2.setChildMeasurementHint(ChildMeasurementHint.MEASURE_IF_NEEDED);
+
+        table3 = createTable();
+        table3.setSizeFull();
+        table3.setChildMeasurementHint(ChildMeasurementHint.MEASURE_NEVER);
+
+        buttonLayout.addComponent(new Button("Show table1",
+                new ClickListener() {
+                    @Override
+                    public void buttonClick(ClickEvent event) {
+                        layout.addComponent(table1);
+                        table1.focus();
+                    }
+                }));
+        buttonLayout.addComponent(new Button("Show table2",
+                new ClickListener() {
+                    @Override
+                    public void buttonClick(ClickEvent event) {
+                        layout.removeComponent(table1);
+                        layout.addComponent(table2);
+                        table2.focus();
+                    }
+                }));
+        buttonLayout.addComponent(new Button("Show table3",
+                new ClickListener() {
+                    @Override
+                    public void buttonClick(ClickEvent event) {
+                        layout.removeComponent(table2);
+                        layout.addComponent(table3);
+                        table3.focus();
+                    }
+                }));
+
+    }
+
+    protected Table createTable() {
+        Table table = new Table();
+        table.setSelectable(true);
+        table.setPageLength(39);
+
+        for (int i = 0; i < 5; i++) {
+            table.addContainerProperty("First_Name" + i, String.class, null);
+            table.addContainerProperty("Last Name" + i, String.class, null);
+            table.addContainerProperty("Year" + i, Integer.class, null);
+        }
+
+        /* Add a few items in the table. */
+        int j = 0;
+        for (int i = 0; i < 2; i++) {
+            table.addItem(
+                    makeRow(new Object[] { "Nicolaus" + i, "Copernicus", 1473 },
+                            5), j++);
+            table.addItem(
+                    makeRow(new Object[] { "Tycho" + i, "Brahe", 1546 }, 5),
+                    j++);
+            table.addItem(
+                    makeRow(new Object[] { "Giordano" + i, "Bruno", 1548 }, 5),
+                    j++);
+            table.addItem(
+                    makeRow(new Object[] { "Galileo" + i, "Galilei", 1564 }, 5),
+                    j++);
+            table.addItem(
+                    makeRow(new Object[] { "Johannes" + i, "Kepler", 1571 }, 5),
+                    j++);
+            table.addItem(
+                    makeRow(new Object[] { "Isaac" + i, "Newton", 1643 }, 5),
+                    j++);
+        }
+
+        table.addGeneratedColumn("First_Name" + 0, new Table.ColumnGenerator() {
+            @Override
+            public Object generateCell(Table components, Object o, Object o2) {
+                ComboBox b = new ComboBox("ComboBox");
+                b.setWidthUndefined();
+                return b;
+            }
+        });
+
+        table.addGeneratedColumn("First_Name" + 1, new Table.ColumnGenerator() {
+            @Override
+            public Object generateCell(Table components, Object o, Object o2) {
+                GridLayout b = new GridLayout();
+                b.addComponents(new Label("l1"), new Button("b"), new Label(
+                        "l2"));
+                b.setWidthUndefined();
+                return b;
+            }
+        });
+
+        table.addGeneratedColumn("First_Name" + 2, new Table.ColumnGenerator() {
+            @Override
+            public Object generateCell(Table components, Object o, Object o2) {
+                Button b = new Button("Button");
+                b.setWidthUndefined();
+                return b;
+            }
+        });
+
+        table.addGeneratedColumn("First_Name" + 3, new Table.ColumnGenerator() {
+            @Override
+            public Object generateCell(Table components, Object o, Object o2) {
+                TextField b = new TextField("Textfield");
+                b.setWidthUndefined();
+                return b;
+            }
+        });
+
+        table.addGeneratedColumn("First_Name" + 4, new Table.ColumnGenerator() {
+            @Override
+            public Object generateCell(Table components, Object o, Object o2) {
+                DateField b = new DateField("DateField");
+                b.setWidthUndefined();
+                return b;
+            }
+        });
+
+        table.addGeneratedColumn("First_Name" + 5, new Table.ColumnGenerator() {
+            @Override
+            public Object generateCell(Table components, Object o, Object o2) {
+                Label b = new Label("Label");
+                b.setWidthUndefined();
+                return b;
+            }
+        });
+
+        return table;
+    }
+
+    protected Object[] makeRow(Object[] data, int c) {
+        Object[] row = new Object[c * data.length];
+        for (int j = 0; j < c; j++) {
+            int x = 0;
+            for (Object value : data) {
+                row[j * data.length + x] = value;
+                x++;
+            }
+        }
+
+        return row;
+    }
+}
\ No newline at end of file
diff --git a/uitest/src/com/vaadin/tests/components/table/TableChildMeasurementHintTest.java b/uitest/src/com/vaadin/tests/components/table/TableChildMeasurementHintTest.java
new file mode 100644
index 0000000000..8202b06362
--- /dev/null
+++ b/uitest/src/com/vaadin/tests/components/table/TableChildMeasurementHintTest.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2000-2014 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.components.table;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import com.vaadin.testbench.elements.ButtonElement;
+import com.vaadin.tests.tb3.MultiBrowserTest;
+
+public class TableChildMeasurementHintTest extends MultiBrowserTest {
+
+    @Test
+    public void testCacheSize() throws IOException {
+
+        openTestURL();
+
+        $(ButtonElement.class).first().click();
+
+        compareScreen("initial");
+
+        $(ButtonElement.class).get(1).click();
+
+        compareScreen("initial");
+
+        $(ButtonElement.class).get(2).click();
+
+        compareScreen("initial");
+    }
+
+}