Class JsonPointerImpl

  • All Implemented Interfaces:
    java.io.Serializable, JsonPointer

    public final class JsonPointerImpl
    extends java.lang.Object
    implements JsonPointer, java.io.Serializable

    This class is an immutable representation of a JSON Pointer as specified in RFC 6901.

    A JSON Pointer, when applied to a target JsonValue, defines a reference location in the target.

    An empty JSON Pointer string defines a reference to the target itself.

    If the JSON Pointer string is non-empty, it must be a sequence of '/' prefixed tokens, and the target must either be a JsonArray or JsonObject. If the target is a JsonArray, the pointer defines a reference to an array element, and the last token specifies the index. If the target is a JsonObject, the pointer defines a reference to a name/value pair, and the last token specifies the name.

    The method getValue() returns the referenced value. The methods add(), replace(), and remove() executes the operations specified in RFC 6902.

    Since:
    1.1
    See Also:
    Serialized Form
    • Field Detail

      • tokens

        private final java.lang.String[] tokens
      • jsonPointer

        private final java.lang.String jsonPointer
    • Constructor Detail

      • JsonPointerImpl

        public JsonPointerImpl​(java.lang.String jsonPointer)
        Constructs and initializes a JsonPointerImpl.
        Parameters:
        jsonPointer - the JSON Pointer string
        Throws:
        java.lang.NullPointerException - if jsonPointer is null
        JsonException - if jsonPointer is not a valid JSON Pointer
    • Method Detail

      • equals

        public boolean equals​(java.lang.Object obj)
        Compares this JsonPointer with another object.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        obj - the object to compare this JsonPointer against
        Returns:
        true if the given object is a JsonPointer with the same reference tokens as this one, false otherwise.
      • hashCode

        public int hashCode()
        Returns the hash code value for this JsonPointer object. The hash code of this object is defined by the hash codes of it's reference tokens.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        the hash code value for this JsonPointer object
      • containsValue

        public boolean containsValue​(JsonStructure target)
        Returns true if there is a value at the referenced location in the specified target.
        Specified by:
        containsValue in interface JsonPointer
        Parameters:
        target - the target referenced by this JsonPointer
        Returns:
        true if this pointer points to a value in a specified target.
      • getValue

        public JsonValue getValue​(JsonStructure target)
        Returns the value at the referenced location in the specified target
        Specified by:
        getValue in interface JsonPointer
        Parameters:
        target - the target referenced by this JsonPointer
        Returns:
        the referenced value in the target.
        Throws:
        java.lang.NullPointerException - if target is null
        JsonException - if the referenced value does not exist
      • add

        public JsonStructure add​(JsonStructure target,
                                 JsonValue value)
        Adds or replaces a value at the referenced location in the specified target with the specified value.
        1. If the reference is the target (empty JSON Pointer string), the specified value, which must be the same type as specified target, is returned.
        2. If the reference is an array element, the specified value is inserted into the array, at the referenced index. The value currently at that location, and any subsequent values, are shifted to the right (adds one to the indices). Index starts with 0. If the reference is specified with a "-", or if the index is equal to the size of the array, the value is appended to the array.
        3. If the reference is a name/value pair of a JsonObject, and the referenced value exists, the value is replaced by the specified value. If the value does not exist, a new name/value pair is added to the object.
        Specified by:
        add in interface JsonPointer
        Parameters:
        target - the target referenced by this JsonPointer
        value - the value to be added
        Returns:
        the transformed target after the value is added.
        Throws:
        java.lang.NullPointerException - if target is null
        JsonException - if the reference is an array element and the index is out of range (index < 0 || index > array size), or if the pointer contains references to non-existing objects or arrays.
      • replace

        public JsonStructure replace​(JsonStructure target,
                                     JsonValue value)
        Replaces the value at the referenced location in the specified target with the specified value.
        Specified by:
        replace in interface JsonPointer
        Parameters:
        target - the target referenced by this JsonPointer
        value - the value to be stored at the referenced location
        Returns:
        the transformed target after the value is replaced.
        Throws:
        java.lang.NullPointerException - if target is null
        JsonException - if the referenced value does not exist, or if the reference is the target.
      • remove

        public JsonStructure remove​(JsonStructure target)
        Removes the value at the reference location in the specified target
        Specified by:
        remove in interface JsonPointer
        Parameters:
        target - the target referenced by this JsonPointer
        Returns:
        the transformed target after the value is removed.
        Throws:
        java.lang.NullPointerException - if target is null
        JsonException - if the referenced value does not exist, or if the reference is the target.
      • execute

        private JsonStructure execute​(java.util.function.BiFunction<NodeReference,​JsonValue,​JsonStructure> op,
                                      JsonStructure target,
                                      JsonValue value)
        Executes the operation
        Parameters:
        op - a {code BiFunction} used to specify the operation to execute on the leaf node of the Json Pointer
        target - the target JsonStructure for this JsonPointer
        value - the JsonValue for add and replace, can be null for getvalue and remove
      • getReferences

        private NodeReference[] getReferences​(JsonStructure target)
        Computes the NodeReferences for each node on the path of the JSON Pointer, in reverse order, starting from the leaf node
      • getIndex

        private static int getIndex​(java.lang.String token)
        Computes the array index
        Parameters:
        token - the input string token
        Returns:
        the array index. -1 if the token is "-"
        Throws:
        JsonException - if the string token is not in correct format