Add ImmutableConfiguration.getDuration() methods.

src/changes/changes.xml

@@ -75,6 +75,9 @@
        <action type="add" dev="ggregory" issue="CONFIGURATION-789" due-to="Gary Gregory">
          Add ImmutableConfiguration.getEnum() methods.
        </action>
+       <action type="add" dev="ggregory" issue="CONFIGURATION-789" due-to="Gary Gregory">
+         Add ImmutableConfiguration.getDuration() methods.
+       </action>       
        <!-- UPDATES -->
        <action type="update" dev="ggregory" issue="CONFIGURATION-787" due-to="Gary Gregory">
          Update from Apache Commons Lang 3.9 to 3.12.0.

src/main/java/org/apache/commons/configuration2/AbstractConfiguration.java

@@ -19,6 +19,7 @@
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -986,6 +987,16 @@ public Double getDouble(final String key, final Double defaultValue) {
         return convert(Double.class, key, defaultValue, false);
     }
 
+    @Override
+    public Duration getDuration(final String key) {
+        return checkNonNullValue(key, convert(Duration.class, key, null, true));
+    }
+
+    @Override
+    public Duration getDuration(final String key, final Duration defaultValue) {
+        return convert(Duration.class, key, defaultValue, false);
+    }
+
     @Override
     public float getFloat(final String key) {
         final Float f = convert(Float.class, key, null, true);

src/main/java/org/apache/commons/configuration2/ImmutableConfiguration.java

@@ -18,11 +18,14 @@
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.time.Duration;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.Properties;
 
+import org.apache.commons.configuration2.convert.PropertyConverter;
 import org.apache.commons.configuration2.ex.ConversionException;
 
 /**
@@ -308,6 +311,38 @@ public interface ImmutableConfiguration {
      */
     Double getDouble(String key, Double defaultValue);
 
+    /**
+     * Gets a {@link Duration} associated with the given configuration key.
+     *
+     * @param key The configuration key.
+     * @return The associated Duration if key is found and has valid format, default value otherwise.
+     * @throws org.apache.commons.configuration2.ex.ConversionException is thrown if the key maps to an object that is not a
+     *         Duration.
+     * @since 2.8.0
+     */
+    default Duration getDuration(final String key) {
+        final String string = getString(key);
+        if (string == null) {
+            throw new NoSuchElementException(key);
+        }
+        return PropertyConverter.toDuration(string);
+    }
+
+    /**
+     * Gets a {@link Duration} associated with the given configuration key.
+     *
+     * @param key The configuration key.
+     * @param defaultValue The default value.
+     * @return The associated Duration if key is found and has valid format, default value otherwise.
+     * @throws org.apache.commons.configuration2.ex.ConversionException is thrown if the key maps to an object that is not a
+     *         Duration.
+     * @since 2.8.0
+     */
+    default Duration getDuration(final String key, final Duration defaultValue) {
+        Object value = getProperty(key);
+        return value == null ? defaultValue : PropertyConverter.toDuration(value);
+    }
+
     /**
      * Gets the value of a string property that is stored in encoded form in this configuration using a default
      * {@code ConfigurationDecoder}. This method works like the method with the same name, but it uses a default

src/main/java/org/apache/commons/configuration2/convert/PropertyConverter.java

@@ -33,6 +33,8 @@
 import java.nio.file.Paths;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
+import java.time.Duration;
+import java.time.format.DateTimeParseException;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.Locale;
@@ -46,9 +48,9 @@
 /**
  * A utility class to convert the configuration properties into any type.
  *
- * @since 1.1
+ * @since 2.8.0
  */
-final class PropertyConverter {
+public final class PropertyConverter {
 
     /** Constant for the prefix of hex numbers. */
     private static final String HEX_PREFIX = "0x";
@@ -150,6 +152,8 @@ public static Object to(final Class<?> cls, final Object value, final DefaultCon
             return toInternetAddress(value);
         } else if (InetAddress.class.isAssignableFrom(cls)) {
             return toInetAddress(value);
+        } else if (Duration.class.equals(cls)) {
+            return toDuration(value);
         }
 
         throw new ConversionException("The value '" + value + "' (" + value.getClass() + ")" + " can't be converted to a " + cls.getName() + " object");
@@ -285,6 +289,28 @@ public static Double toDouble(final Object value) throws ConversionException {
         return Double.valueOf(n.doubleValue());
     }
 
+    /**
+     * Convert the specified object into a Duration.
+     *
+     * @param value the value to convert
+     * @return the converted value
+     * @throws ConversionException thrown if the value cannot be converted to a Duration
+     * @since 2.8.0
+     */
+    public static Duration toDuration(final Object value) throws ConversionException {
+        if (value instanceof Duration) {
+            return (Duration) value;
+        }
+        if (value instanceof CharSequence) {
+            try {
+                return Duration.parse((CharSequence) value);
+            } catch (DateTimeParseException e) {
+                throw new ConversionException("Could not convert " + value + " to Duration", e);
+            }
+        }
+        throw new ConversionException("The value " + value + " can't be converted to a Duration");
+    }
+
     /**
      * Convert the specified object into a BigInteger.
      *

src/test/java/org/apache/commons/configuration2/TestBaseConfiguration.java

@@ -26,6 +26,7 @@
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -307,6 +308,29 @@ public void testGetDoubleUnknown() {
         config.getDouble("numberNotInConfig");
     }
 
+    @Test
+    public void testGetDuration() {
+        final Duration d = Duration.ofSeconds(1);
+        config.setProperty("durationD", d.toString());
+        final Duration oneD = Duration.ofSeconds(1);
+        final Duration twoD = Duration.ofSeconds(2);
+        assertEquals("This returns 1(Duration)", oneD, config.getDuration("durationD"));
+        assertEquals("This returns 1(Duration)", oneD, config.getDuration("durationD", twoD));
+        assertEquals("This returns 2(default Duration)", twoD, config.getDuration("numberNotInConfig", twoD));
+        assertEquals("This returns 1(Duration)", oneD, config.getDuration("durationD", twoD));
+    }
+
+    @Test(expected = ConversionException.class)
+    public void testGetDurationIncompatibleType() {
+        config.setProperty("test.empty", "");
+        config.getDuration("test.empty");
+    }
+
+    @Test(expected = NoSuchElementException.class)
+    public void testGetDurationUnknown() {
+        config.getDuration("numberNotInConfig");
+    }
+
     @Test
     public void testGetEnum() {
         config.setProperty("testEnum", EnumFixture.SMALLTALK.name());