Added method to convert a (decimal) String to Long

src/main/java/com/rometools/utils/Longs.java

@@ -0,0 +1,25 @@
+package com.rometools.utils;
+
+public final class Longs {
+
+    private Longs() {
+    }
+
+    /**
+     * Converts a String into a Long by first parsing it as Double and then casting it to Long.
+     *
+     * @param s The String to convert, may be null or in decimal format
+     * @return The parsed Long or null when parsing is not possible
+     */
+    public static Long parseDecimal(final String s) {
+        Long parsed = null;
+        try {
+            if (s != null) {
+                parsed = (long) Double.parseDouble(s);
+            }
+        } catch (final NumberFormatException e) {
+        }
+        return parsed;
+    }
+
+}

src/test/java/com/rometools/utils/LongsTest.java

@@ -0,0 +1,26 @@
+package com.rometools.utils;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
+
+import org.junit.Test;
+
+public class LongsTest {
+
+    @Test
+    public void testParseDecimal() {
+
+        final String nullString = null;
+        final String emptyString = "";
+        final String longString = String.valueOf(Long.MAX_VALUE);
+        final String decimalString = String.valueOf(Double.MAX_VALUE);
+
+        assertThat(Longs.parseDecimal(nullString), is(nullValue()));
+        assertThat(Longs.parseDecimal(emptyString), is(nullValue()));
+        assertThat(Longs.parseDecimal(longString), is(Long.MAX_VALUE));
+        assertThat(Longs.parseDecimal(decimalString), is((long) Double.MAX_VALUE));
+
+    }
+
+}