Adds src/main/java/org/javamoney/moneta/ScaleRoundedOperator.java

src/main/java/org/javamoney/moneta/MathContextRoundedOperator.java

@@ -10,7 +10,18 @@
 /**
  * <p>This implementation uses a {@link MathContext} to does the rounding operations. The implementation will use the <b>precision</b>, in other words, the total number of digits in a number</p>
  * <p>The derived class will implements the {@link RoundedMoney} with this rounding monetary operator</p>
- * <p>Case the parameter in {@link MonetaryOperator#apply(MonetaryAmount)} be null, the apply will return a {@link NullPointerException}</p>
+ *  <pre>
+ *   {@code
+ *
+ *     MathContext mathContext = new MathContext(4, RoundingMode.HALF_EVEN);
+ *     MonetaryOperator monetaryOperator = MathContextRoundedOperator.of(mathContext);
+ *     CurrencyUnit real = Monetary.getCurrency("BRL");
+ *     MonetaryAmount money = Money.of(BigDecimal.valueOf(35.34567), real);
+ *     MonetaryAmount result = monetaryOperator.apply(money); // BRL 35.35
+ *
+ *    }
+* </pre>
+* <p>Case the parameter in {@link MonetaryOperator#apply(MonetaryAmount)} be null, the apply will return a {@link NullPointerException}</p>
  * @author Otavio Santana
  * @see {@link MathContextRoundedOperator#of(MathContext)}
  * @see {@link RoundedMoney}

src/main/java/org/javamoney/moneta/ScaleRoundedOperator.java

@@ -0,0 +1,70 @@
+package org.javamoney.moneta;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.math.RoundingMode;
+import java.util.Objects;
+
+import javax.money.MonetaryAmount;
+import javax.money.MonetaryOperator;
+
+/**
+ * <p>This implementation uses a scale and {@link RoundingMode} to does the rounding operations. The implementation will use the <b>scale</b>, in other words, the number of digits to the right of the decimal point</p>
+ * <p>The derived class will implements the {@link RoundedMoney} with this rounding monetary operator</p>
+ *  <pre>
+ *   {@code
+ *
+ *     MonetaryOperator monetaryOperator = ScaleRoundedOperator.of(scale, RoundingMode.HALF_EVEN);
+ *     CurrencyUnit real = Monetary.getCurrency("BRL");
+ *     MonetaryAmount money = Money.of(BigDecimal.valueOf(35.34567), real);
+ *     MonetaryAmount result = monetaryOperator.apply(money); // BRL 35.3457
+ *
+ *    }
+* </pre>
+ * <p>Case the parameter in {@link MonetaryOperator#apply(MonetaryAmount)} be null, the apply will return a {@link NullPointerException}</p>
+ * @author Otavio Santana
+ * @see {@link ScaleRoundedOperator#of(MathContext)}
+ * @see {@link RoundedMoney}
+ * @see {@link MonetaryOperator}
+ * @see {@link BigDecimal#scale()}
+ */
+public final class ScaleRoundedOperator implements MonetaryOperator {
+
+	private final int scale;
+
+	private final RoundingMode roundingMode;
+
+	private ScaleRoundedOperator(int scale, RoundingMode roundingMode) {
+		this.scale = scale;
+		this.roundingMode = roundingMode;
+	}
+
+	/**
+	 * Creates the rounded Operator from scale and roundingMode
+	 * @param mathContext
+	 * @return the {@link MonetaryOperator} using the scale and {@link roundingMode} used in parameter
+	 * @throws NullPointerException when the {@link MathContext} is null
+	 * @see {@linkplain RoundingMode}
+	 */
+	public static ScaleRoundedOperator of(int scale, RoundingMode roundingMode) {
+		return new ScaleRoundedOperator(scale, Objects.requireNonNull(roundingMode));
+	}
+
+	@Override
+	public MonetaryAmount apply(MonetaryAmount amount) {
+		RoundedMoney roundedMoney = RoundedMoney.from(Objects.requireNonNull(amount));
+		BigDecimal numberValue = roundedMoney.getNumber().numberValue(BigDecimal.class);
+		BigDecimal numberRounded = numberValue.setScale(scale, roundingMode);
+		return RoundedMoney.of(numberRounded, roundedMoney.getCurrency(), this);
+	}
+
+	@Override
+	public String toString() {
+		StringBuilder sb = new StringBuilder();
+		sb.append(ScaleRoundedOperator.class.getName()).append('{')
+		.append("scale:").append(Integer.toString(scale)).append(',')
+		.append("roundingMode:").append(roundingMode).append('}');
+		return sb.toString();
+	}
+
+}

src/test/java/org/javamoney/moneta/MathContextRoundedOperatorTest.java

@@ -32,17 +32,18 @@ public void shouldReturnErrorWhenParameterIsNUll() {
 
 	@Test
 	public void shouldRoundedMonetaryOperatorWhenTheImplementationIsMoney() {
-		int scale = 2;
+		int scale = 4;
 		MathContext mathContext = new MathContext(scale, RoundingMode.HALF_EVEN);
 
 		CurrencyUnit real = Monetary.getCurrency("BRL");
-		Money money = Money.of(BigDecimal.valueOf(130002.56895), real);
+		MonetaryAmount money = Money.of(BigDecimal.valueOf(35.34567), real);
 
 		MathContextRoundedOperator monetaryOperator = MathContextRoundedOperator.of(mathContext);
 		MonetaryAmount result = monetaryOperator.apply(money);
 		assertTrue(RoundedMoney.class.isInstance(result));
 		assertEquals(result.getCurrency(), real);
 		assertEquals(result.getNumber().getPrecision(), scale);
+		assertEquals(BigDecimal.valueOf(35.35), result.getNumber().numberValue(BigDecimal.class));
 
 
 

src/test/java/org/javamoney/moneta/ScaleRoundedOperatorTest.java

@@ -0,0 +1,48 @@
+package org.javamoney.moneta;
+
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.fail;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+import javax.money.CurrencyUnit;
+import javax.money.Monetary;
+import javax.money.MonetaryAmount;
+
+import org.testng.annotations.Test;
+
+public class ScaleRoundedOperatorTest {
+
+	@Test(expectedExceptions = NullPointerException.class)
+	public void shouldReturnNullPointerExceptionWhenParameterIsNull() {
+		ScaleRoundedOperator.of(0, null);
+		fail();
+	}
+
+	@Test(expectedExceptions = NullPointerException.class)
+	public void shouldReturnErrorWhenParameterIsNUll() {
+		ScaleRoundedOperator monetaryOperator = ScaleRoundedOperator.of(0, RoundingMode.HALF_EVEN);
+		monetaryOperator.apply(null);
+		fail();
+	}
+
+	@Test
+	public void shouldRoundedMonetaryOperatorWhenTheImplementationIsMoney() {
+		int scale = 4;
+
+		CurrencyUnit real = Monetary.getCurrency("BRL");
+		MonetaryAmount money = Money.of(BigDecimal.valueOf(35.34567), real);
+
+		ScaleRoundedOperator monetaryOperator = ScaleRoundedOperator.of(scale, RoundingMode.HALF_EVEN);
+		MonetaryAmount result = monetaryOperator.apply(money);
+		assertTrue(RoundedMoney.class.isInstance(result));
+		assertEquals(result.getCurrency(), real);
+		assertEquals(result.getNumber().getScale(), scale);
+		assertEquals(BigDecimal.valueOf(35.3457), result.getNumber().numberValue(BigDecimal.class));
+
+
+
+	}
+}