Lazy big decimal parsing (#830)

Author: pjfanning

src/main/java/com/fasterxml/jackson/core/base/ParserBase.java

@@ -207,7 +207,7 @@ public abstract class ParserBase extends ParserMinimalBase
      * Textual number representation captured from input in cases lazy-parsing
      * is desired.
      *<p>
-     * As of 2.14 this only applies to {@link BigInteger}.
+     * As of 2.14, this only applies to {@link BigInteger} and {@link BigDecimal}.
      *
      * @since 2.14
      */
@@ -625,7 +625,7 @@ public Number getNumberValue() throws IOException
         // And then floating point types. But here optimal type
         // needs to be big decimal, to avoid losing any data?
         if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
-            return _numberBigDecimal;
+            return _getBigDecimal();
         }
         if ((_numTypesValid & NR_FLOAT) != 0) {
             return _numberFloat;
@@ -660,7 +660,7 @@ public Number getNumberValueExact() throws IOException
             _parseNumericValue(NR_BIGDECIMAL);
         }
         if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
-            return _numberBigDecimal;
+            return _getBigDecimal();
         }
         if ((_numTypesValid & NR_FLOAT) != 0) {
             return _numberFloat;
@@ -791,7 +791,7 @@ public BigDecimal getDecimalValue() throws IOException
                 convertNumberToBigDecimal();
             }
         }
-        return _numberBigDecimal;
+        return _getBigDecimal();
     }
 
     /*
@@ -900,7 +900,8 @@ private void _parseSlowFloat(int expType) throws IOException
          */
         try {
             if (expType == NR_BIGDECIMAL) {
-                _numberBigDecimal = _textBuffer.contentsAsDecimal();
+                _numberBigDecimal = null;
+                _numberString = _textBuffer.contentsAsString();
                 _numTypesValid = NR_BIGDECIMAL;
             } else if (expType == NR_FLOAT) {
                 _numberFloat = _textBuffer.contentsAsFloat(isEnabled(Feature.USE_FAST_DOUBLE_PARSER));
@@ -992,11 +993,12 @@ protected void convertNumberToInt() throws IOException
             }
             _numberInt = (int) _numberDouble;
         } else if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
-            if (BD_MIN_INT.compareTo(_numberBigDecimal) > 0 
-                || BD_MAX_INT.compareTo(_numberBigDecimal) < 0) {
+            final BigDecimal bigDecimal = _getBigDecimal();
+            if (BD_MIN_INT.compareTo(bigDecimal) > 0
+                || BD_MAX_INT.compareTo(bigDecimal) < 0) {
                 reportOverflowInt();
             }
-            _numberInt = _numberBigDecimal.intValue();
+            _numberInt = bigDecimal.intValue();
         } else {
             _throwInternal();
         }
@@ -1021,11 +1023,12 @@ protected void convertNumberToLong() throws IOException
             }
             _numberLong = (long) _numberDouble;
         } else if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
-            if (BD_MIN_LONG.compareTo(_numberBigDecimal) > 0 
-                || BD_MAX_LONG.compareTo(_numberBigDecimal) < 0) {
+            final BigDecimal bigDecimal = _getBigDecimal();
+            if (BD_MIN_LONG.compareTo(bigDecimal) > 0
+                || BD_MAX_LONG.compareTo(bigDecimal) < 0) {
                 reportOverflowLong();
             }
-            _numberLong = _numberBigDecimal.longValue();
+            _numberLong = bigDecimal.longValue();
         } else {
             _throwInternal();
         }
@@ -1036,7 +1039,7 @@ protected void convertNumberToBigInteger() throws IOException
     {
         if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
             // here it'll just get truncated, no exceptions thrown
-            _numberBigInt = _numberBigDecimal.toBigInteger();
+            _numberBigInt = _getBigDecimal().toBigInteger();
         } else if ((_numTypesValid & NR_LONG) != 0) {
             _numberBigInt = BigInteger.valueOf(_numberLong);
         } else if ((_numTypesValid & NR_INT) != 0) {
@@ -1058,7 +1061,7 @@ protected void convertNumberToDouble() throws IOException
          */
 
         if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
-            _numberDouble = _numberBigDecimal.doubleValue();
+            _numberDouble = _getBigDecimal().doubleValue();
         } else if ((_numTypesValid & NR_BIGINT) != 0) {
             _numberDouble = _getBigInteger().doubleValue();
         } else if ((_numTypesValid & NR_LONG) != 0) {
@@ -1082,7 +1085,7 @@ protected void convertNumberToFloat() throws IOException
          */
 
         if ((_numTypesValid & NR_BIGDECIMAL) != 0) {
-            _numberFloat = _numberBigDecimal.floatValue();
+            _numberFloat = _getBigDecimal().floatValue();
         } else if ((_numTypesValid & NR_BIGINT) != 0) {
             _numberFloat = _getBigInteger().floatValue();
         } else if ((_numTypesValid & NR_LONG) != 0) {
@@ -1137,6 +1140,23 @@ protected BigInteger _getBigInteger() {
         _numberString = null;
         return _numberBigInt;
     }
+
+    /**
+     * Internal accessor that needs to be used for accessing number value of type
+     * {@link BigDecimal} which -- as of 2.14 -- is typically lazily parsed.
+     *
+     * @since 2.14
+     */
+    protected BigDecimal _getBigDecimal() {
+        if (_numberBigDecimal != null) {
+            return _numberBigDecimal;
+        } else if (_numberString == null) {
+            throw new IllegalStateException("cannot get BigDecimal from current parser state");
+        }
+        _numberBigDecimal = NumberInput.parseBigDecimal(_numberString);
+        _numberString = null;
+        return _numberBigDecimal;
+    }
 
     /*
     /**********************************************************
@@ -1374,4 +1394,5 @@ protected void loadMoreGuaranteed() throws IOException {
 
     // Can't declare as deprecated, for now, but shouldn't be needed
     protected void _finishString() throws IOException { }
+
 }