Fix #296

release-notes/CREDITS

@@ -93,3 +93,7 @@ Tanguy Leroux (tlrx@github)
 Mikael Staldal (mikaelstaldal@github)
   * Contributed fix for #265: `JsonStringEncoder` should allow passing `CharSequence`
    (2.8.0)
+
+Kevin Gallardo (newkek@github)
+  * Reported #296: JsonParserSequence skips a token on a switched Parser
+   (2.8.0)

release-notes/VERSION

@@ -39,6 +39,8 @@ JSON library.
 #290: Add `JsonGenerator.canWriteFormattedNumbers()` for introspection
 #294: Add `JsonGenerator.writeFieldId(long)` method to support binary formats
  with non-String keys
+#296: JsonParserSequence skips a token on a switched Parser
+ (reported by Kevin G)
 - Add `JsonParser.currentToken()` and `JsonParser.currentTokenId()` as replacements
   for `getCurrentToken()` and `getCurrentTokenId()`, respectively. Existing methods
   will likely be deprecated in 2.9.

src/main/java/com/fasterxml/jackson/core/JsonGenerator.java

@@ -1681,7 +1681,7 @@ public void writeOmittedField(String fieldName) throws IOException { }
      */
     public void copyCurrentEvent(JsonParser p) throws IOException
     {
-        JsonToken t = p.getCurrentToken();
+        JsonToken t = p.currentToken();
         // sanity check; what to do?
         if (t == null) {
             _reportError("No current event to copy");
@@ -1784,7 +1784,7 @@ public void copyCurrentEvent(JsonParser p) throws IOException
      */
     public void copyCurrentStructure(JsonParser p) throws IOException
     {
-        JsonToken t = p.getCurrentToken();
+        JsonToken t = p.currentToken();
         if (t == null) {
             _reportError("No current event to copy");
         }

src/main/java/com/fasterxml/jackson/core/JsonParser.java

@@ -884,7 +884,7 @@ public int currentTokenId() {
     /**
      * Method that is functionally equivalent to:
      *<code>
-     *  return getCurrentTokenId() == id
+     *  return currentTokenId() == id
      *</code>
      * but may be more efficiently implemented.
      *<p>
@@ -899,7 +899,7 @@ public int currentTokenId() {
     /**
      * Method that is functionally equivalent to:
      *<code>
-     *  return getCurrentTokenId() == id
+     *  return currentToken() == t
      *</code>
      * but may be more efficiently implemented.
      *<p>
@@ -956,23 +956,23 @@ public int currentTokenId() {
      *<p>
      * Default implementation is equivalent to:
      *<pre>
-     *   getCurrentToken() == JsonToken.START_ARRAY
+     *   currentToken() == JsonToken.START_ARRAY
      *</pre>
      * but may be overridden by custom parser implementations.
      *
      * @return True if the current token can be considered as a
      *   start-array marker (such {@link JsonToken#START_ARRAY});
      *   false if not.
      */
-    public boolean isExpectedStartArrayToken() { return getCurrentToken() == JsonToken.START_ARRAY; }
+    public boolean isExpectedStartArrayToken() { return currentToken() == JsonToken.START_ARRAY; }
 
     /**
      * Similar to {@link #isExpectedStartArrayToken()}, but checks whether stream
      * currently points to {@link JsonToken#START_OBJECT}.
-     * 
+     *
      * @since 2.5
      */
-    public boolean isExpectedStartObjectToken() { return getCurrentToken() == JsonToken.START_OBJECT; }
+    public boolean isExpectedStartObjectToken() { return currentToken() == JsonToken.START_OBJECT; }
 
     /*
     /**********************************************************
@@ -1285,12 +1285,12 @@ public short getShortValue() throws IOException
      * may be thrown to indicate numeric overflow/underflow.
      */
     public boolean getBooleanValue() throws IOException {
-        JsonToken t = getCurrentToken();
+        JsonToken t = currentToken();
         if (t == JsonToken.VALUE_TRUE) return true;
         if (t == JsonToken.VALUE_FALSE) return false;
         throw new JsonParseException(this,
-                String.format("Current token (%s) not of boolean type", t))
-        .withRequestPayload(_requestPayload);
+            String.format("Current token (%s) not of boolean type", t))
+                .withRequestPayload(_requestPayload);
     }
 
     /**

src/main/java/com/fasterxml/jackson/core/filter/FilteringParserDelegate.java

@@ -146,11 +146,16 @@ public int getMatchCount() {
      */
 
     @Override public JsonToken getCurrentToken() { return _currToken; }
+    @Override public JsonToken currentToken() { return _currToken; }
 
     @Override public final int getCurrentTokenId() {
         final JsonToken t = _currToken;
         return (t == null) ? JsonTokenId.ID_NO_TOKEN : t.id();
     }
+    @Override public final int currentTokenId() {
+        final JsonToken t = _currToken;
+        return (t == null) ? JsonTokenId.ID_NO_TOKEN : t.id();
+    }
 
     @Override public boolean hasCurrentToken() { return _currToken != null; }
     @Override public boolean hasTokenId(int id) {

src/main/java/com/fasterxml/jackson/core/util/JsonParserSequence.java

@@ -25,6 +25,14 @@ public class JsonParserSequence extends JsonParserDelegate
      * Index of the next parser in {@link #_parsers}.
      */
     protected int _nextParser;
+
+    /**
+     * Flag used to indicate that `JsonParser.nextToken()` should not be called,
+     * due to parser already pointing to a token.
+     *
+     * @since 2.8
+     */
+    protected boolean _suppressNextToken;
 
     /*
      *******************************************************
@@ -35,6 +43,7 @@ public class JsonParserSequence extends JsonParserDelegate
     protected JsonParserSequence(JsonParser[] parsers)
     {
         super(parsers[0]);
+        _suppressNextToken = delegate.hasCurrentToken();
         _parsers = parsers;
         _nextParser = 1;
     }
@@ -94,15 +103,21 @@ public void close() throws IOException {
     }
 
     @Override
-    public JsonToken nextToken() throws IOException, JsonParseException
+    public JsonToken nextToken() throws IOException
     {
+        if (delegate == null) {
+            return null;
+        }
+        if (_suppressNextToken) {
+            _suppressNextToken = false;
+            return delegate.currentToken();
+        }
         JsonToken t = delegate.nextToken();
-        if (t != null) return t;
-        while (switchToNext()) {
-            t = delegate.nextToken();
-            if (t != null) return t;
+        while ((t == null) && switchToNext()) {
+            t = delegate.hasCurrentToken()
+                    ? delegate.currentToken() : delegate.nextToken();
         }
-        return null;
+        return t;
     }
 
     /*

src/test/java/com/fasterxml/jackson/core/json/ParserSequenceTest.java

@@ -3,6 +3,7 @@
 import com.fasterxml.jackson.core.*;
 import com.fasterxml.jackson.core.util.JsonParserSequence;
 
+@SuppressWarnings("resource")
 public class ParserSequenceTest
     extends com.fasterxml.jackson.core.BaseTest
 {
@@ -43,8 +44,22 @@ public void testSimple() throws Exception
         assertTrue(seq.isClosed());
 
         seq.close();
-        // redundant, but call to remove IDE warnings
-        p1.close();
-        p2.close();
+    }
+
+    // for [jackson-core#296]
+    public void testInitialized() throws Exception
+    {
+        JsonParser p1 = JSON_FACTORY.createParser("1 2");
+        JsonParser p2 = JSON_FACTORY.createParser("3 false");
+        // consume '1', move to '2'
+        assertToken(JsonToken.VALUE_NUMBER_INT, p1.nextToken());
+        assertToken(JsonToken.VALUE_NUMBER_INT, p1.nextToken());
+
+        JsonParserSequence seq = JsonParserSequence.createFlattened(p1, p2);
+        assertToken(JsonToken.VALUE_NUMBER_INT, seq.nextToken());
+        assertEquals(2, seq.getIntValue());
+        assertToken(JsonToken.VALUE_NUMBER_INT, seq.nextToken());
+        assertEquals(3, seq.getIntValue());
+        seq.close();
     }
 }

src/test/java/com/fasterxml/jackson/core/json/StringGenerationTest.java

@@ -287,7 +287,7 @@ private void _testLongerRandomMulti(int readMode, String text, boolean charArray
             }
             offset += act.length();
         }
-        assertEquals(JsonToken.END_ARRAY, p.getCurrentToken());
+        assertEquals(JsonToken.END_ARRAY, p.currentToken());
         p.close();
     }
 }

src/test/java/com/fasterxml/jackson/core/json/TestParserOverrides.java

@@ -45,14 +45,14 @@ public void _testTokenAccess(JsonFactory jf, boolean useStream) throws Exception
         JsonParser jp = useStream ?
                 jf.createParser(new ByteArrayInputStream(DOC.getBytes("UTF-8")))
                 : jf.createParser(DOC);
-        assertNull(jp.getCurrentToken());
+        assertNull(jp.currentToken());
         jp.clearCurrentToken();
-        assertNull(jp.getCurrentToken());
+        assertNull(jp.currentToken());
         assertNull(jp.getEmbeddedObject());
         assertToken(JsonToken.START_ARRAY, jp.nextToken());
-        assertToken(JsonToken.START_ARRAY, jp.getCurrentToken());
+        assertToken(JsonToken.START_ARRAY, jp.currentToken());
         jp.clearCurrentToken();
-        assertNull(jp.getCurrentToken());
+        assertNull(jp.currentToken());
         // Also: no codec defined by default
         try {
             jp.readValueAsTree();
@@ -69,7 +69,7 @@ private void _testCurrentName(JsonFactory jf, boolean useStream) throws Exceptio
         JsonParser jp = useStream ?
                 jf.createParser(new ByteArrayInputStream(DOC.getBytes("UTF-8")))
                 : jf.createParser(new StringReader(DOC));
-        assertNull(jp.getCurrentToken());
+        assertNull(jp.currentToken());
         assertToken(JsonToken.START_OBJECT, jp.nextToken());
         assertToken(JsonToken.FIELD_NAME, jp.nextToken());
         assertEquals("first", jp.getCurrentName());
@@ -94,9 +94,7 @@ private void _testCurrentName(JsonFactory jf, boolean useStream) throws Exceptio
 
         assertToken(JsonToken.END_OBJECT, jp.nextToken());
         jp.clearCurrentToken();
-        assertNull(jp.getCurrentToken());
+        assertNull(jp.currentToken());
         jp.close();
     }
-
-
 }

src/test/java/com/fasterxml/jackson/core/json/TestRootValues.java

@@ -45,7 +45,7 @@ private void _testBrokeanNumber(boolean useStream) throws Exception
         // Should fail, right away
         try {
         	p.nextToken();
-        	fail("Ought to fail! Instead, got token: "+p.getCurrentToken());
+        	fail("Ought to fail! Instead, got token: "+p.currentToken());
         } catch (JsonParseException e) {
         	verifyException(e, "unexpected character");
         }

src/test/java/com/fasterxml/jackson/core/main/TestGeneratorCopy.java

@@ -26,7 +26,7 @@ public void testCopyRootTokens()
         while ((t = jp.nextToken()) != null) {
             gen.copyCurrentEvent(jp);
             // should not change parser state:
-            assertToken(t, jp.getCurrentToken());
+            assertToken(t, jp.currentToken());
         }
         jp.close();
         gen.close();
@@ -46,14 +46,14 @@ public void testCopyArrayTokens()
         assertToken(JsonToken.VALUE_NUMBER_INT, jp.nextToken());
         gen.copyCurrentEvent(jp);
         // should not change parser state:
-        assertToken(JsonToken.VALUE_NUMBER_INT, jp.getCurrentToken());
+        assertToken(JsonToken.VALUE_NUMBER_INT, jp.currentToken());
         assertEquals(123, jp.getIntValue());
 
         // And then let's copy the array
         assertToken(JsonToken.START_ARRAY, jp.nextToken());
         gen.copyCurrentStructure(jp);
         // which will advance parser to matching close Array
-        assertToken(JsonToken.END_ARRAY, jp.getCurrentToken());
+        assertToken(JsonToken.END_ARRAY, jp.currentToken());
         jp.close();
         gen.close();
 
@@ -72,7 +72,7 @@ public void testCopyObjectTokens()
         assertToken(JsonToken.START_OBJECT, jp.nextToken());
         gen.copyCurrentStructure(jp);
         // which will advance parser to matching end Object
-        assertToken(JsonToken.END_OBJECT, jp.getCurrentToken());
+        assertToken(JsonToken.END_OBJECT, jp.currentToken());
         jp.close();
         gen.close();
 

src/test/java/com/fasterxml/jackson/core/read/JsonParserTest.java

@@ -226,7 +226,7 @@ private void _testSkipping(int mode) throws Exception
         // First, skipping of the whole thing
         assertToken(JsonToken.START_ARRAY, p.nextToken());
         p.skipChildren();
-        assertEquals(JsonToken.END_ARRAY, p.getCurrentToken());
+        assertEquals(JsonToken.END_ARRAY, p.currentToken());
         if (!isInputData) {
             JsonToken t = p.nextToken();
             if (t != null) {
@@ -242,27 +242,27 @@ private void _testSkipping(int mode) throws Exception
         assertToken(JsonToken.VALUE_NUMBER_INT, p.nextToken());
         p.skipChildren();
         // shouldn't move
-        assertToken(JsonToken.VALUE_NUMBER_INT, p.getCurrentToken());
+        assertToken(JsonToken.VALUE_NUMBER_INT, p.currentToken());
         assertEquals(1, p.getIntValue());
 
         assertToken(JsonToken.VALUE_NUMBER_INT, p.nextToken());
         // then skip array
         assertToken(JsonToken.START_ARRAY, p.nextToken());
         p.skipChildren();
-        assertToken(JsonToken.END_ARRAY, p.getCurrentToken());
+        assertToken(JsonToken.END_ARRAY, p.currentToken());
 
         assertToken(JsonToken.VALUE_NUMBER_INT, p.nextToken());
         assertToken(JsonToken.START_OBJECT, p.nextToken());
         p.skipChildren();
-        assertToken(JsonToken.END_OBJECT, p.getCurrentToken());
+        assertToken(JsonToken.END_OBJECT, p.currentToken());
 
         assertToken(JsonToken.START_ARRAY, p.nextToken());
         p.skipChildren();
-        assertToken(JsonToken.END_ARRAY, p.getCurrentToken());
+        assertToken(JsonToken.END_ARRAY, p.currentToken());
 
         assertToken(JsonToken.START_OBJECT, p.nextToken());
         p.skipChildren();
-        assertToken(JsonToken.END_OBJECT, p.getCurrentToken());
+        assertToken(JsonToken.END_OBJECT, p.currentToken());
 
         assertToken(JsonToken.END_ARRAY, p.nextToken());
 

src/test/java/com/fasterxml/jackson/core/util/TestDelegates.java

@@ -18,7 +18,7 @@ public void testParserDelegate() throws IOException
         JsonParser parser = JSON_F.createParser("[ 1, true, null, { } ]");
         JsonParserDelegate del = new JsonParserDelegate(parser);
 
-        assertNull(del.getCurrentToken());
+        assertNull(del.currentToken());
         assertToken(JsonToken.START_ARRAY, del.nextToken());
         assertEquals("[", del.getText());
         assertToken(JsonToken.VALUE_NUMBER_INT, del.nextToken());