Handle 'z' (timezone) in AbstractDateField.setDateFormat() (#8844)

2 files changed, 201 insertions, 0 deletions

diff --git a/server/src/main/java/com/vaadin/ui/AbstractDateField.java b/server/src/main/java/com/vaadin/ui/AbstractDateField.java
index bc6b5f49a8..b5f11f7122 100644
--- a/server/src/main/java/com/vaadin/ui/AbstractDateField.java
+++ b/server/src/main/java/com/vaadin/ui/AbstractDateField.java
@@ -19,6 +19,7 @@ import java.io.Serializable;
 import java.lang.reflect.Type;
 import java.text.SimpleDateFormat;
 import java.time.LocalDate;
+import java.time.ZoneId;
 import java.time.temporal.Temporal;
 import java.time.temporal.TemporalAdjuster;
 import java.util.Calendar;
@@ -56,6 +57,7 @@ import com.vaadin.shared.ui.datefield.DateFieldConstants;
 import com.vaadin.shared.ui.datefield.DateResolution;
 import com.vaadin.ui.declarative.DesignAttributeHandler;
 import com.vaadin.ui.declarative.DesignContext;
+import com.vaadin.util.TimeZoneUtil;
 
 /**
  * A date editor component with {@link LocalDate} as an input value.
@@ -95,6 +97,8 @@ public abstract class AbstractDateField<T extends Temporal & TemporalAdjuster &
      */
     private String dateFormat;
 
+    private ZoneId zoneId;
+
     private boolean lenient = false;
 
     private String dateString = "";
@@ -445,6 +449,53 @@ public abstract class AbstractDateField<T extends Temporal & TemporalAdjuster &
     }
 
     /**
+     * Sets the {@link ZoneId}, which is used when {@code z} is included inside
+     * the {@link #setDateFormat(String)}.
+     *
+     * @param zoneId
+     *            the zone id
+     * @since 8.2
+     */
+    public void setZoneId(ZoneId zoneId) {
+        if (zoneId != this.zoneId
+                || (zoneId != null && !zoneId.equals(this.zoneId))) {
+            updateTimeZoneJSON(zoneId, getLocale());
+        }
+        this.zoneId = zoneId;
+    }
+
+    private void updateTimeZoneJSON(ZoneId zoneId, Locale locale) {
+        String timeZoneJSON;
+        if (zoneId != null && locale != null) {
+            timeZoneJSON = TimeZoneUtil.toJSON(zoneId, locale);
+        } else {
+            timeZoneJSON = null;
+        }
+        getState().timeZoneJSON = timeZoneJSON;
+    }
+
+    @Override
+    public void setLocale(Locale locale) {
+        Locale oldLocale = getLocale();
+        if (locale != oldLocale
+                || (locale != null && !locale.equals(oldLocale))) {
+            updateTimeZoneJSON(getZoneId(), locale);
+        }
+        super.setLocale(locale);
+    }
+
+    /**
+     * Returns the {@link ZoneId}, which is used when {@code z} is included
+     * inside the {@link #setDateFormat(String)}.
+     *
+     * @return the zoneId
+     * @since 8.2
+     */
+    public ZoneId getZoneId() {
+        return zoneId;
+    }
+
+    /**
      * Specifies whether or not date/time interpretation in component is to be
      * lenient.
      *
diff --git a/server/src/main/java/com/vaadin/util/TimeZoneUtil.java b/server/src/main/java/com/vaadin/util/TimeZoneUtil.java
new file mode 100644
index 0000000000..ec3d28e730
--- /dev/null
+++ b/server/src/main/java/com/vaadin/util/TimeZoneUtil.java
@@ -0,0 +1,150 @@
+/*
+ * 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.util;
+
+import java.io.Serializable;
+import java.time.Duration;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.zone.ZoneOffsetTransition;
+import java.time.zone.ZoneRules;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+import java.util.TimeZone;
+
+import elemental.json.JsonArray;
+import elemental.json.JsonObject;
+import elemental.json.impl.JreJsonFactory;
+import elemental.json.impl.JsonUtil;
+
+/**
+ * Utilities related to {@link com.google.gwt.i18n.client.TimeZone}.
+ *
+ * @author Vaadin Ltd
+ * @since 8.2
+ */
+public final class TimeZoneUtil implements Serializable {
+
+    /**
+     * The start year used to send the time zone transition dates.
+     */
+    private static final int STARTING_YEAR = 1980;
+
+    /**
+     * Till how many years from now, should we send the time zone transition
+     * dates.
+     */
+    private static final int YEARS_FROM_NOW = 20;
+
+    private TimeZoneUtil() {
+        // Static utils only
+    }
+
+    /**
+     * Returns a JSON string of the specified {@code zoneId} and {@link Locale},
+     * which is used in
+     * {@link com.google.gwt.i18n.client.TimeZone#createTimeZone(String)}.
+     *
+     * @param zoneId
+     *            the {@link ZoneId} to get the daylight transitions from
+     * @param locale
+     *            the locale used to determine the short name of the time zone
+     *
+     * @return the encoded string
+     */
+    public static String toJSON(ZoneId zoneId, Locale locale) {
+        if (zoneId == null || locale == null) {
+            return null;
+        }
+        ZoneRules rules = zoneId.getRules();
+        TimeZone timeZone = TimeZone.getTimeZone(zoneId);
+        List<Long> transitionsList = new ArrayList<>();
+
+        TimeZoneInfo info = new TimeZoneInfo();
+
+        int endYear = LocalDate.now().getYear() + YEARS_FROM_NOW;
+        if (timeZone.useDaylightTime()) {
+            for (int year = STARTING_YEAR; year <= endYear; year++) {
+                ZonedDateTime i = LocalDateTime.of(year, 1, 1, 0, 0)
+                        .atZone(zoneId);
+                while (true) {
+                    ZoneOffsetTransition t = rules
+                            .nextTransition(i.toInstant());
+                    if (t == null) {
+                        break;
+                    }
+                    i = t.getInstant().atZone(zoneId);
+                    if (i.toLocalDate().getYear() != year) {
+                        break;
+                    }
+                    long epocHours = Duration
+                            .ofSeconds(t.getInstant().getEpochSecond())
+                            .toHours();
+                    long duration = Math.max(t.getDuration().toMinutes(), 0);
+                    transitionsList.add(epocHours);
+                    transitionsList.add(duration);
+                }
+            }
+        }
+        info.id = zoneId.getId();
+        info.transitions = transitionsList.stream().mapToLong(l -> l).toArray();
+        info.std_offset = (int) Duration.ofMillis(timeZone.getRawOffset())
+                .toMinutes();
+        info.names = new String[] {
+                timeZone.getDisplayName(false, TimeZone.SHORT, locale),
+                timeZone.getDisplayName(false, TimeZone.LONG, locale),
+                timeZone.getDisplayName(true, TimeZone.SHORT, locale),
+                timeZone.getDisplayName(true, TimeZone.LONG, locale) };
+
+        return stringify(info);
+    }
+
+    private static String stringify(TimeZoneInfo info) {
+        JreJsonFactory factory = new JreJsonFactory();
+        JsonObject object = factory.createObject();
+        object.put("id", info.id);
+        object.put("std_offset", info.std_offset);
+        object.put("names", getArray(factory, info.names));
+        object.put("transitions", getArray(factory, info.transitions));
+        return JsonUtil.stringify(object);
+    }
+
+    private static JsonArray getArray(JreJsonFactory factory, long[] array) {
+        JsonArray jsonArray = factory.createArray();
+        for (int i = 0; i < array.length; i++) {
+            jsonArray.set(i, array[i]);
+        }
+        return jsonArray;
+    }
+
+    private static JsonArray getArray(JreJsonFactory factory, String[] array) {
+        JsonArray jsonArray = factory.createArray();
+        for (int i = 0; i < array.length; i++) {
+            jsonArray.set(i, array[i]);
+        }
+        return jsonArray;
+    }
+
+    private static class TimeZoneInfo implements Serializable {
+        String id;
+        int std_offset;
+        String[] names;
+        long[] transitions;
+    }
+}