Add identity method in MonetaryOperator

Author: otaviojava

src/etc/jsr354-api clean install.launch

@@ -58,7 +58,8 @@ public RoundingQueryBuilder createRoundingQueryBuilder() {
      *
      * @return the default rounding, never null.
      */
-    public MonetaryRounding getDefaultRounding() {
+    @Override
+	public MonetaryRounding getDefaultRounding() {
         return DEFAULT_ROUNDING;
     }
 
@@ -132,7 +133,8 @@ public List<String> getDefaultProviderChain() {
      *                  #getDefaultProviders is used, not null.
      * @return the set of custom rounding ids, never {@code null}.
      */
-    public Set<String> getRoundingNames(String... providers) {
+    @Override
+	public Set<String> getRoundingNames(String... providers) {
         Set<String> result = new HashSet<>();
         String[] providerNames = providers;
         if (providerNames.length == 0) {
@@ -161,7 +163,9 @@ public Set<String> getRoundingNames(String... providers) {
      */
     private static final class DefaultCurrencyRounding implements MonetaryRounding, Serializable {
 
-        private static final RoundingContext ROUNDING_CONTEXT = RoundingContextBuilder.of("default", "default").build();
+		private static final long serialVersionUID = 8641545296538357839L;
+
+		private static final RoundingContext ROUNDING_CONTEXT = RoundingContextBuilder.of("default", "default").build();
 
         @Override
         public MonetaryAmount apply(MonetaryAmount amount) {

src/main/java/javax/money/DefaultMonetaryRoundingsSingletonSpi.java

@@ -5,14 +5,15 @@
  * DOWNLOADING THIS SPECIFICATION, YOU ACCEPT THE TERMS AND CONDITIONS OF THE
  * AGREEMENT. IF YOU ARE NOT WILLING TO BE BOUND BY IT, SELECT THE "DECLINE"
  * BUTTON AT THE BOTTOM OF THIS PAGE.
- * 
+ *
  * Specification: JSR-354 Money and Currency API ("Specification")
- * 
+ *
  * Copyright (c) 2012-2015, Credit Suisse All rights reserved.
  */
 package javax.money;
 
 
+
 /**
  * Represents an operation on a single {@link MonetaryAmount} that produces a
  * result of type {@link MonetaryAmount}.
@@ -23,16 +24,16 @@
  * There are two equivalent ways of using a {@code MonetaryOperator}. The first
  * is to invoke the method on this interface. The second is to use
  * {@link MonetaryAmount#with(MonetaryOperator)}:
- * 
+ *
  * <pre>
  * // these two lines are equivalent, but the second approach is recommended
  * monetary = thisOperator.apply(monetary);
  * monetary = monetary.with(thisOperator);
  * </pre>
- * 
+ *
  * It is recommended to use the second approach, {@code with(MonetaryOperator)},
  * as it is a lot clearer to read in code.
- * 
+ *
  * <h4>Implementation specification</h4>
  * The implementation must take the input object and apply it. The
  * implementation defines the logic of the operator and is responsible for
@@ -45,13 +46,13 @@
  * <p>
  * This method may be called from multiple threads in parallel. It must be
  * thread-safe when invoked.
- * 
+ *
  * <p>
  * This interface extends {@code java.util.function.UnaryOperator} introduced by Java 8.
- * 
+ *
  * @author Werner Keil
  * @author Anatole Tresch
- * 
+ *
  * @version 0.9
  */
 @FunctionalInterface
@@ -63,4 +64,12 @@ public interface MonetaryOperator{
      * @return the applied amount.
      */
     MonetaryAmount apply(MonetaryAmount amount);
+
+    /**
+     * Returns a function that always returns its input argument.
+     * @return an operator  that always returns its input argument
+     */
+    static MonetaryOperator identity() {
+        return m -> m;
+    }
 }