Add target constants for Anchor to use with alternate setTarget method

flow-html-components/src/main/java/com/vaadin/flow/component/html/Anchor.java

@@ -15,7 +15,9 @@
  */
 package com.vaadin.flow.component.html;
 
+import java.util.Objects;
 import java.util.Optional;
+import java.util.stream.Stream;
 
 import com.vaadin.flow.component.Component;
 import com.vaadin.flow.component.Focusable;
@@ -39,7 +41,7 @@ public class Anchor extends HtmlContainer implements Focusable<Anchor> {
             .attributeWithDefault("href", "", false);
 
     private static final PropertyDescriptor<String, Optional<String>> targetDescriptor = PropertyDescriptors
-            .optionalAttributeWithDefault("target", "");
+            .optionalAttributeWithDefault("target", AnchorTarget.DEFAULT.getValue());
 
     private static final String ROUTER_IGNORE_ATTRIBUTE = "router-ignore";
 
@@ -66,6 +68,26 @@ public Anchor(String href, String text) {
         setText(text);
     }
 
+    /**
+     * Creates an anchor component with the given target, text content and href.
+     *
+     * @see #setHref(String)
+     * @see #setText(String)
+     * @see #setTargetEnum(AnchorTarget)
+     *
+     * @param href
+     *            the href to set
+     * @param text
+     *            the text content to set
+     * @param target
+     *            the target window, tab or frame
+     */
+    public Anchor(String href, String text, AnchorTarget target) {
+        setHref(href);
+        setText(text);
+        setTargetEnum(target);
+    }
+
     /**
      * Creates an anchor component with the given text content and stream
      * resource.
@@ -183,4 +205,47 @@ public Optional<String> getTarget() {
         return get(targetDescriptor);
     }
 
+    /**
+     * Sets the target window, tab or frame for this anchor. The target is one of these
+     * special values:
+     * <ul>
+     * <li><code>AnchorTarget.DEFAULT</code>: Removes the target value. This has the same effect as setting the target to <code>AnchorTarget.SELF</code>.
+     * <li><code>AnchorTarget.SELF</code>: Opens the link in the current context.
+     * <li><code>AnchorTarget.BLANK</code>: Opens the link in a new unnamed context.
+     * <li><code>AnchorTarget.PARENT</code>: Opens the link in the parent context, or the
+     * current context if there is no parent context.
+     * <li><code>AnchorTarget.TOP</code>: Opens the link in the top most grandparent
+     * context, or the current context if there is no parent context.
+     * </ul>
+     *
+     * @param target
+     *            the target value, not null
+     */
+    public void setTargetEnum(AnchorTarget target) {
+        Objects.requireNonNull(target, "target cannot be null.");
+        setTarget(target.getValue());
+    }
+
+    /**
+     * Gets the target window, tab or frame value for this anchor.
+     *
+     * @see #setTargetEnum(AnchorTarget)
+     *
+     * @return an optional target, or an empty optional if no target has been
+     *         set
+     */
+    public Optional<AnchorTarget> getTargetEnum() {
+        Optional<AnchorTarget> anchorTarget = Optional.empty();
+
+        Optional<String> strTarget = getTarget();
+
+        if (strTarget.isPresent()) {
+            String valueToFind = strTarget.get();
+            anchorTarget = Stream.of(AnchorTarget.values()).filter(type-> type.getValue().equals(valueToFind))
+                    .findFirst();
+        }
+
+        return anchorTarget;
+    }
+
 }

flow-html-components/src/main/java/com/vaadin/flow/component/html/AnchorTarget.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2000-2020 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.flow.component.html;
+
+/**
+ * Enum representing <code>target</code> attribute values for an <code>&lt;a&gt;</code> element.
+ *
+ * @author Vaadin Ltd
+ * @since
+ */
+public enum AnchorTarget {
+    /**
+     * Remove the target value. This has the same effect as <code>SELF</code>.
+     */
+    DEFAULT(""),
+    /**
+     * Open a link in the current context.
+     */
+    SELF("_self"),
+    /**
+     * Open a link in a new unnamed context.
+     */
+    BLANK("_blank"),
+    /**
+     * Open a link in the parent context, or the current context if there is no
+     * parent context.
+     */
+    PARENT("_parent"),
+    /**
+     * Open a link in the top most grandparent
+     * context, or the current context if there is no parent context.
+     */
+    TOP("_top");
+
+    private final String value;
+
+    /**
+     * @param value the text value to use by an {@code <a>} (anchor) tag.
+     */
+    AnchorTarget(String value) {
+        this.value = value;
+    }
+
+    /**
+     * @return
+     *         value the text value to use by an {@code <a>} (anchor) tag.
+     */
+    String getValue() {
+        return value;
+    }
+
+}

flow-html-components/src/test/java/com/vaadin/flow/component/html/AnchorTest.java

@@ -19,6 +19,8 @@
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.util.Optional;
+
 public class AnchorTest extends ComponentTest {
 
     @Test
@@ -35,7 +37,24 @@ public void removeHref() {
     public void createWithComponent() {
         Anchor anchor = new Anchor("#", new Text("Home"));
         Assert.assertEquals(anchor.getElement().getAttribute("href"), "#");
+        Assert.assertEquals(anchor.getHref(), "#");
         Assert.assertEquals(anchor.getElement().getText(), "Home");
+        Assert.assertEquals(anchor.getText(), "Home");
+    }
+
+    @Test
+    public void createWithTarget() {
+        Anchor anchor = new Anchor("#", "Home");
+        Assert.assertEquals(anchor.getTargetEnum(), Optional.empty());
+        Assert.assertEquals(anchor.getTarget(), Optional.empty());
+
+        anchor.setTargetEnum(AnchorTarget.BLANK);
+
+        Assert.assertEquals(anchor.getTargetEnum(), Optional.of(AnchorTarget.BLANK));
+        Assert.assertEquals(anchor.getTarget(), Optional.of(AnchorTarget.BLANK.getValue()));
+
+        Assert.assertEquals(anchor.getTargetEnum(), new Anchor("#", "Home", AnchorTarget.BLANK).getTargetEnum());
+        Assert.assertEquals(anchor.getTarget(), new Anchor("#", "Home", AnchorTarget.BLANK).getTarget());
     }
 
     @Test

flow-html-components/src/test/java/com/vaadin/flow/component/html/HtmlComponentSmokeTest.java

@@ -61,6 +61,7 @@ public class HtmlComponentSmokeTest {
         testValues.put(int.class, 42);
         testValues.put(IFrame.ImportanceType.class, IFrame.ImportanceType.HIGH);
         testValues.put(IFrame.SandboxType[].class, new IFrame.SandboxType[] { IFrame.SandboxType.ALLOW_POPUPS, IFrame.SandboxType.ALLOW_MODALS });
+        testValues.put(AnchorTarget.class, AnchorTarget.TOP);
     }
 
     // For classes registered here testStringConstructor will be ignored. This test checks whether the content of the