Add getStartLocation() in JsonStreamContext, to allow access for non-standard read contexts

Author: cowtowncoder

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

@@ -42,6 +42,17 @@ public abstract class JsonStreamContext
 
     protected JsonStreamContext() { }
 
+    /**
+     * Copy constructor used by sub-classes for creating copies for
+     * buffering.
+     *
+     * @since 2.9
+     */
+    protected JsonStreamContext(JsonStreamContext base) {
+        _type = base._type;
+        _index = base._index;
+    }
+
     /*
     /**********************************************************
     /* Public API, accessors
@@ -203,11 +214,29 @@ public JsonPointer pathAsPointer() {
      * "root value index"
      *
      * @param includeRoot Whether root-value offset is included as the first segment or not;
-     *    
      *
      * @since 2.9
      */
     public JsonPointer pathAsPointer(boolean includeRoot) {
         return JsonPointer.forPath(this, includeRoot);
     }
+
+    /**
+     * Optional method that may be used to access starting location of this context:
+     * for example, in case of JSON `Object` context, offset at which `[` token was
+     * read or written. Often used for error reporting purposes.
+     * Implementations that do not keep track of such location are expected to return
+     * {@link JsonLocation#NA}; this is what the default implementation does.
+     *
+     * @return Location pointing to the point where the context
+     *   start marker was found (or written); never `null`.
+     *<p>
+     * NOTE: demoted from <code>JsonReadContext</code> in 2.9, to allow use for
+     * "non-standard" read contexts.
+     *
+     * @since 2.9
+     */
+    public JsonLocation getStartLocation(Object srcRef) {
+        return JsonLocation.NA;
+    }
 }

src/main/java/com/fasterxml/jackson/core/json/JsonReadContext.java

@@ -135,7 +135,7 @@ public JsonReadContext createChildObjectContext(int lineNr, int colNr) {
 
     /*
     /**********************************************************
-    /* Abstract method implementation
+    /* Abstract method implementations, overrides
     /**********************************************************
      */
 
@@ -146,6 +146,19 @@ public JsonReadContext createChildObjectContext(int lineNr, int colNr) {
 
     @Override public JsonReadContext getParent() { return _parent; }
 
+    @Override
+    public JsonLocation getStartLocation(Object srcRef) {
+        // We don't keep track of offsets at this level (only reader does)
+        long totalChars = -1L;
+        return new JsonLocation(srcRef, totalChars, _lineNr, _columnNr);
+    }
+
+    /*
+    /**********************************************************
+    /* Extended API
+    /**********************************************************
+     */
+
     /**
      * Method that can be used to both clear the accumulated references
      * (specifically value set with {@link #setCurrentValue(Object)})
@@ -162,22 +175,6 @@ public JsonReadContext clearAndGetParent() {
         return _parent;
     }
 
-    /*
-    /**********************************************************
-    /* Extended API
-    /**********************************************************
-     */
-
-    /**
-     * @return Location pointing to the point where the context
-     *   start marker was found
-     */
-    public JsonLocation getStartLocation(Object srcRef) {
-        // We don't keep track of offsets at this level (only reader does)
-        long totalChars = -1L;
-        return new JsonLocation(srcRef, totalChars, _lineNr, _columnNr);
-    }
-
     public DupDetector getDupDetector() {
         return _dups;
     }

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

@@ -237,7 +237,7 @@ protected DefaultPrettyPrinter _withSpaces(boolean state)
     public DefaultPrettyPrinter createInstance() {
         return new DefaultPrettyPrinter(this);
     }
-    
+
     /*
     /**********************************************************
     /* PrettyPrinter impl