added parseFromISO87String and toISO87String

suggested in jpos-users by Bjarne Henriksen - THANK YOU!

jpos/src/main/java/org/jpos/iso/ISOCurrency.java

@@ -20,6 +20,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.math.BigDecimal;
 import java.util.*;
 
 /**
@@ -88,12 +89,27 @@ public static void loadPropertiesFromClasspath(String base)
      * @param currency  - The ISO currency to be converted (eg. ISOField 49)
      * @return result - A double representing the converted field
      * @throws IllegalArgumentException if we fail to convert the amount
+     * @deprecated You should never use doubles
      */
     public static double convertFromIsoMsg(String isoamount, String currency) throws IllegalArgumentException
     {
         Currency c = findCurrency(currency);
         return c.parseAmountFromISOMsg(isoamount);
     }
+    public static String toISO87String (BigDecimal amount, String currency)
+    {
+        try {
+            Currency c = findCurrency(currency);
+            return ISOUtil.zeropad(amount.movePointRight(c.getDecimals()).setScale(0).toPlainString(), 12);
+        }
+        catch (ISOException e) {
+            throw new IllegalArgumentException("Failed to convert amount",e);
+        }
+    }
+    public static BigDecimal parseFromISO87String (String isoamount, String currency) {
+        int decimals = findCurrency(currency).getDecimals();
+        return new BigDecimal(isoamount).movePointLeft(decimals);
+    }
 
     public static void addBundle(ResourceBundle r)
     {

jpos/src/test/java/org/jpos/util/ISOCurrencyTest.java

@@ -0,0 +1,41 @@
+/*
+ * jPOS Project [http://jpos.org]
+ * Copyright (C) 2000-2014 Alejandro P. Revilla
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.jpos.util;
+
+import org.jpos.iso.ISOCurrency;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+import java.math.BigDecimal;
+
+@SuppressWarnings("unused")
+public class ISOCurrencyTest {
+    @Test
+    public void testparseFromISO87String () {
+        assertEquals("2 decimals",  new BigDecimal("12.34"), ISOCurrency.parseFromISO87String("000000001234", "840"));
+        assertEquals("3 decimals",  new BigDecimal("1.234"), ISOCurrency.parseFromISO87String("000000001234", "048"));
+        assertEquals("no decimals", new BigDecimal("1234"),  ISOCurrency.parseFromISO87String("000000001234", "020"));
+    }
+    @Test
+    public void testtoISO87String () {
+        assertEquals("2 decimals",  "000000001234", ISOCurrency.toISO87String(new BigDecimal("12.34"), "840"));
+        assertEquals("3 decimals",  "000000001234", ISOCurrency.toISO87String(new BigDecimal("1.234"), "048"));
+        assertEquals("no decimals", "000000001234", ISOCurrency.toISO87String(new BigDecimal("1234"),  "020"));
+    }
+}