Add formatter to handle file sizes from ingest summary queries

ace-am/src/main/java/edu/umiacs/ace/util/FileSizeFormatter.java

+package edu.umiacs.ace.util;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+/**
+ * Similar to the {@link FileSizeHandler}, but for KiB/MiB/etc when
+ * we may not have access to the tlds
+ *
+ * Created by shake on 4/4/17.
+ */
+public class FileSizeFormatter {
+
+    private Unit unit;
+
+    public FileSizeFormatter(String unit) {
+        this.unit = Unit.fromString(unit);
+    }
+
+    public String format(BigDecimal decimal) {
+        BigDecimal result = decimal.divide(unit.divisor, 5, RoundingMode.HALF_UP);
+        String displayUnit = unit == Unit.B ? "" : unit.name();
+        return result.stripTrailingZeros().toPlainString() + " " + displayUnit;
+    }
+
+    public enum Unit {
+        B(0), KiB(1), MiB(2), GiB(3), TiB(4);
+
+        private BigDecimal divisor;
+
+        Unit(int pow) {
+            this.divisor = new BigDecimal(Math.pow(1024, pow));
+        }
+
+        private static Unit fromString(String unit) {
+            if (unit == null) {
+                return B;
+            }
+
+            if (unit.equalsIgnoreCase("kib")) {
+                return KiB;
+            } else if (unit.equalsIgnoreCase("mib")) {
+                return MiB;
+            } else if (unit.equalsIgnoreCase("gib")) {
+                return GiB;
+            } else if (unit.equalsIgnoreCase("tib")) {
+                return TiB;
+            }
+
+            return B;
+        }
+
+    }
+
+}