Prototype extract method in rule

ThreeTen · Jan 30, 2012 · 5dd3eae · 5dd3eae
1 parent 56cab54
commit 5dd3eae
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diff --git a/src/main/java/javax/time/ExtendedCalendricalRule.java b/src/main/java/javax/time/ExtendedCalendricalRule.java
@@ -31,11 +31,14 @@
  */
 package javax.time;
 
+import static javax.time.calendrical.ISODateTimeRule.ZERO_EPOCH_MONTH;
+
 import java.io.Serializable;
 
 import javax.time.calendrical.CalendricalEngine;
 import javax.time.calendrical.CalendricalRule;
 import javax.time.calendrical.DateTimeField;
+import javax.time.calendrical.ISOChronology;
 import javax.time.calendrical.ISODateTimeRule;
 
 /**
@@ -88,6 +91,39 @@ private Object readResolve() {
         return RULE_CACHE[ordinal];
     }
 
+    //-----------------------------------------------------------------------
+    @SuppressWarnings("unchecked")
+    @Override
+    public <R> R extract(CalendricalRule<R> ruleToExtract, T calendrical) {
+        if (ruleToExtract == this) {
+            return (R) calendrical;
+        }
+        switch (ordinal) {
+            case YEAR_ORDINAL:
+                Year y = (Year) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ISOChronology.INSTANCE, ISODateTimeRule.YEAR.field(y.getValue()));
+            case YEAR_MONTH_ORDINAL:
+                YearMonth ym = (YearMonth) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ISOChronology.INSTANCE, ZERO_EPOCH_MONTH.field(ym.toZeroEpochMonth()));
+            case MONTH_DAY_ORDINAL:
+                MonthDay md = (MonthDay) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, null, null, null, null, ISOChronology.INSTANCE, md.toFields());
+            case MONTH_OF_YEAR_ORDINAL:
+                MonthOfYear moy = (MonthOfYear) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ISOChronology.INSTANCE, ISODateTimeRule.MONTH_OF_YEAR.field(moy.getValue()));
+            case QUARTER_OF_YEAR_ORDINAL:
+                QuarterOfYear qoy = (QuarterOfYear) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ISOChronology.INSTANCE, ISODateTimeRule.QUARTER_OF_YEAR.field(qoy.getValue()));
+            case DAY_OF_WEEK_ORDINAL:
+                DayOfWeek dow = (DayOfWeek) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ISOChronology.INSTANCE, ISODateTimeRule.DAY_OF_WEEK.field(dow.getValue()));
+            case AM_PM_OF_DAY_ORDINAL:
+                AmPmOfDay amPm = (AmPmOfDay) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ISOChronology.INSTANCE, ISODateTimeRule.AMPM_OF_DAY.field(amPm.getValue()));
+        }
+        return null;
+    }
+
     //-----------------------------------------------------------------------
     @SuppressWarnings("unchecked")
     @Override

diff --git a/src/main/java/javax/time/ISOCalendricalRule.java b/src/main/java/javax/time/ISOCalendricalRule.java
@@ -40,6 +40,7 @@
 import javax.time.calendrical.CalendricalEngine;
 import javax.time.calendrical.CalendricalRule;
 import javax.time.calendrical.DateTimeField;
+import javax.time.calendrical.ISOChronology;
 
 /**
  * Internal class supplying the rules for the principal date and time objects.
@@ -94,8 +95,42 @@ private Object readResolve() {
     //-----------------------------------------------------------------------
     @SuppressWarnings("unchecked")
     @Override
-    protected T deriveFrom(CalendricalEngine engine) {
+    public <R> R extract(CalendricalRule<R> ruleToExtract, T calendrical) {
+        if (ruleToExtract == this) {
+            return (R) calendrical;
+        }
         switch (ordinal) {
+            case LOCAL_DATE_ORDINAL:
+                return CalendricalEngine.derive(ruleToExtract, this, (LocalDate) calendrical, null, null, null, ISOChronology.INSTANCE, null);
+            case LOCAL_TIME_ORDINAL:
+                return CalendricalEngine.derive(ruleToExtract, this, null, (LocalTime) calendrical, null, null, ISOChronology.INSTANCE, null);
+            case LOCAL_DATE_TIME_ORDINAL:
+                LocalDateTime ldt = (LocalDateTime) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, ldt.toLocalDate(), ldt.toLocalTime(), null, null, ISOChronology.INSTANCE, null);
+            case OFFSET_DATE_ORDINAL:
+                OffsetDate od = (OffsetDate) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, od.toLocalDate(), null, od.getOffset(), null, ISOChronology.INSTANCE, null);
+            case OFFSET_TIME_ORDINAL:
+                OffsetTime ot = (OffsetTime) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, null, ot.toLocalTime(), ot.getOffset(), null, ISOChronology.INSTANCE, null);
+            case OFFSET_DATE_TIME_ORDINAL:
+                OffsetDateTime odt = (OffsetDateTime) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, odt.toLocalDate(), odt.toLocalTime(), odt.getOffset(), null, ISOChronology.INSTANCE, null);
+            case ZONED_DATE_TIME_ORDINAL:
+                ZonedDateTime zdt = (ZonedDateTime) calendrical;
+                return CalendricalEngine.derive(ruleToExtract, this, zdt.toLocalDate(), zdt.toLocalTime(), zdt.getOffset(), zdt.getZone(), ISOChronology.INSTANCE, null);
+            case ZONE_OFFSET_ORDINAL:
+                return CalendricalEngine.derive(ruleToExtract, this, null, null, (ZoneOffset) calendrical, null, ISOChronology.INSTANCE, null);
+            case ZONE_ID_ORDINAL:
+                return CalendricalEngine.derive(ruleToExtract, this, null, null, null, (ZoneId) calendrical, ISOChronology.INSTANCE, null);
+        }
+        return null;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    protected T deriveFrom(CalendricalEngine engine) {
+       switch (ordinal) {
             case LOCAL_DATE_ORDINAL: return (T) engine.getDate(true);
             case LOCAL_TIME_ORDINAL: {
                 LocalTime time = engine.getTime(false);

diff --git a/src/main/java/javax/time/YearMonth.java b/src/main/java/javax/time/YearMonth.java
@@ -602,6 +602,18 @@ public LocalDate atDay(int dayOfMonth, DateResolver dateResolver) {
     }
 
     //-----------------------------------------------------------------------
+    /**
+     * Converts this {@code YearMonth} to a count of months.
+     * <p>
+     * The Zero Epoch Month count is a simple incrementing count of months
+     * where month 0 is 0000-01-01 using ISO proleptic years.
+     *
+     * @return the count of months
+     */
+    public long toZeroEpochMonth() {
+        return year * 12L + month.ordinal();
+    }
+
     /**
      * Converts this year-month to an equivalent fields object.
      * <p>

diff --git a/src/main/java/javax/time/calendrical/CalendricalRule.java b/src/main/java/javax/time/calendrical/CalendricalRule.java
@@ -36,6 +36,7 @@
 import java.util.List;
 
 import javax.time.CalendricalException;
+import javax.time.LocalDate;
 
 /**
  * A rule defining how a single well-defined calendrical element operates.
@@ -127,6 +128,21 @@ public final Class<T> getType() {
         return type;
     }
 
+    //-----------------------------------------------------------------------
+    /**
+     * Extracts the value of the specified rule from an instance of the class
+     * this rule manages.
+     *
+     * @param ruleToExtract  the rule to extract, not null
+     * @param calendrical  the calendrical to get the field value from, not null
+     * @return the value of the specified rule, null if unable to extract the field
+     */
+    public <R> R extract(CalendricalRule<R> ruleToExtract, T calendrical) {
+        ISOChronology.checkNotNull(ruleToExtract, "CalendricalRule must not be null");
+        ISOChronology.checkNotNull(calendrical, "Calendrical must not be null");
+        return (R) ((Calendrical) calendrical).get(ruleToExtract);
+    }
+
     //-----------------------------------------------------------------------
     /**
      * Gets the value of this rule from the specified calendrical returning
@@ -255,4 +271,38 @@ public String toString() {
         return name;
     }
 
+    //-------------------------------------------------------------------------
+    /**
+     * Rule class.
+     *
+     */
+    static class LocalDateRule extends CalendricalRule<LocalDate> implements Serializable {
+        static final CalendricalRule<LocalDate> INSTANCE = new LocalDateRule();
+        private static final long serialVersionUID = 1L;
+
+        private LocalDateRule() {
+            super(LocalDate.class, "LocalDate");
+        }
+        private Object readResolve() {
+            return INSTANCE;
+        }
+
+        @SuppressWarnings("unchecked")
+        @Override
+        public <R> R extract(CalendricalRule<R> ruleToExtract, LocalDate calendrical) {
+            if (ruleToExtract == this) {
+                return (R) calendrical;
+            }
+            if (ruleToExtract instanceof ISODateTimeRule) {
+                return (R) ((ISODateTimeRule) ruleToExtract).deriveFrom(calendrical, null, null);
+            }
+            return CalendricalEngine.derive(ruleToExtract, INSTANCE, calendrical, null, null, null, ISOChronology.INSTANCE, null);
+        }
+
+        @Override
+        protected LocalDate deriveFrom(CalendricalEngine engine) {
+            return engine.getDate(true);
+        }
+    }
+
 }
diff --git a/src/test/java/javax/time/TestYearMonth.java b/src/test/java/javax/time/TestYearMonth.java
@@ -1072,6 +1072,18 @@ public void test_atDay_intDateResolver_resolved() {
         assertEquals(test.atDay(31, DateResolvers.previousValid()), LocalDate.of(2008, 6, 30));
     }
 
+    //-----------------------------------------------------------------------
+    // toZeroEpochMonth()
+    //-----------------------------------------------------------------------
+    public void test_toZeroEpochMonth() {
+        assertEquals(YearMonth.of(0, 1).toZeroEpochMonth(), 0);
+        assertEquals(YearMonth.of(0, 2).toZeroEpochMonth(), 1);
+        assertEquals(YearMonth.of(0, 12).toZeroEpochMonth(), 11);
+        assertEquals(YearMonth.of(1, 1).toZeroEpochMonth(), 12);
+        assertEquals(YearMonth.of(-1, 12).toZeroEpochMonth(), -1);
+        assertEquals(YearMonth.of(2010, 6).toZeroEpochMonth(), 2010 * 12L + 5);
+    }
+
     //-----------------------------------------------------------------------
     // toFields()
     //-----------------------------------------------------------------------