Monetary: Add parseCoinInexact() and parseFiatInexact() variants that will cut the amount to the smallest unit.

core/src/main/java/org/bitcoinj/core/Coin.java

@@ -116,12 +116,16 @@ public final class Coin implements Monetary, Comparable<Coin>, Serializable {
     }
 
     /**
-     * Parses an amount expressed in the way humans are used to.<p>
+     * <p>
+     * Parses an amount expressed in the way humans are used to.
      * <p/>
-     * This takes string in a format understood by {@link BigDecimal#BigDecimal(String)},
+     * <p>
-     * for example "0", "1", "0.10", "1.23E3", "1234.5E-5".
+     * This takes string in a format understood by {@link BigDecimal#BigDecimal(String)}, for example "0", "1", "0.10",
+     * "1.23E3", "1234.5E-5".
+     * </p>
      *
-     * @throws IllegalArgumentException if you try to specify fractional satoshis, or a value out of range.
+     * @throws IllegalArgumentException
+     *             if you try to specify fractional satoshis, or a value out of range.
      */
     public static Coin parseCoin(final String str) {
         try {
@@ -132,6 +136,27 @@ public final class Coin implements Monetary, Comparable<Coin>, Serializable {
         }
     }
 
+    /**
+     * <p>
+     * Parses an amount expressed in the way humans are used to. The amount is cut to satoshi precision.
+     * <p/>
+     * <p>
+     * This takes string in a format understood by {@link BigDecimal#BigDecimal(String)}, for example "0", "1", "0.10",
+     * "1.23E3", "1234.5E-5".
+     * <p/>
+     *
+     * @throws IllegalArgumentException
+     *             if you try to specify a value out of range.
+     */
+    public static Coin parseCoinInexact(final String str) {
+        try {
+            long satoshis = new BigDecimal(str).movePointRight(SMALLEST_UNIT_EXPONENT).longValue();
+            return Coin.valueOf(satoshis);
+        } catch (ArithmeticException e) {
+            throw new IllegalArgumentException(e); // Repackage exception to honor method contract
+        }
+    }
+
     public Coin add(final Coin value) {
         return new Coin(LongMath.checkedAdd(this.value, value.value));
     }

core/src/main/java/org/bitcoinj/utils/Fiat.java

@@ -73,11 +73,13 @@ public final class Fiat implements Monetary, Comparable<Fiat>, Serializable {
     }
 
     /**
-     * Parses an amount expressed in the way humans are used to.
      * <p>
+     * Parses an amount expressed in the way humans are used to.
      * <p/>
+     * <p>
      * This takes string in a format understood by {@link BigDecimal#BigDecimal(String)}, for example "0", "1", "0.10",
      * "1.23E3", "1234.5E-5".
+     * <p/>
      *
      * @throws IllegalArgumentException
      *             if you try to specify more than 4 digits after the comma, or a value out of range.
@@ -91,6 +93,27 @@ public final class Fiat implements Monetary, Comparable<Fiat>, Serializable {
         }
     }
 
+    /**
+     * <p>
+     * Parses an amount expressed in the way humans are used to. The amount is cut to 4 digits after the comma.
+     * <p/>
+     * <p>
+     * This takes string in a format understood by {@link BigDecimal#BigDecimal(String)}, for example "0", "1", "0.10",
+     * "1.23E3", "1234.5E-5".
+     * <p/>
+     *
+     * @throws IllegalArgumentException
+     *             if you try to specify a value out of range.
+     */
+    public static Fiat parseFiatInexact(final String currencyCode, final String str) {
+        try {
+            long val = new BigDecimal(str).movePointRight(SMALLEST_UNIT_EXPONENT).longValue();
+            return Fiat.valueOf(currencyCode, val);
+        } catch (ArithmeticException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+
     public Fiat add(final Fiat value) {
         checkArgument(value.currencyCode.equals(currencyCode));
         return new Fiat(currencyCode, LongMath.checkedAdd(this.value, value.value));

core/src/test/java/org/bitcoinj/core/CoinTest.java

@@ -42,6 +42,19 @@ public class CoinTest {
         } catch (Exception e) {
             org.junit.Assert.fail("should throw IllegalArgumentException");
         }
+        assertEquals(1, parseCoin("0.00000001").value);
+        assertEquals(1, parseCoin("0.000000010").value);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testParseCoinOverprecise() {
+        parseCoin("0.000000011");
+    }
+
+    @Test
+    public void testParseCoinInexact() {
+        assertEquals(1, parseCoinInexact("0.00000001").value);
+        assertEquals(1, parseCoinInexact("0.000000011").value);
     }
 
     @Test

core/src/test/java/org/bitcoinj/utils/FiatTest.java

@@ -31,6 +31,23 @@ public class FiatTest {
         assertEquals(Fiat.valueOf("EUR", -10000), parseFiat("EUR", "-1"));
     }
 
+    @Test
+    public void testParseFiat() {
+        assertEquals(1, Fiat.parseFiat("EUR", "0.0001").value);
+        assertEquals(1, Fiat.parseFiat("EUR", "0.00010").value);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testParseFiatOverprecise() {
+        Fiat.parseFiat("EUR", "0.00011");
+    }
+
+    @Test
+    public void testParseFiatInexact() {
+        assertEquals(1, Fiat.parseFiatInexact("EUR", "0.0001").value);
+        assertEquals(1, Fiat.parseFiatInexact("EUR", "0.00011").value);
+    }
+
     @Test
     public void testToFriendlyString() {
         assertEquals("1.00 EUR", parseFiat("EUR", "1").toFriendlyString());