Interface TreeNode

Method Details

• asToken

  JsonToken asToken()

  Method that can be used for efficient type detection when using stream abstraction for traversing nodes. Will return the first JsonToken that equivalent stream event would produce (for most nodes there is just one token but for structured/container types multiple)

  Returns:

  JsonToken that is most closely associated with the node type

• numberType

  JsonParser.NumberType numberType()

  If this node is a numeric type (as per JsonToken.isNumeric()), returns native type that node uses to store the numeric value; otherwise returns null.

  Returns:

  Type of number contained, if any; or null if node does not contain numeric value.

• size

  int size()

  Method that returns number of child nodes this node contains: for Array nodes, number of child elements, for Object nodes, number of fields, and for all other nodes 0.

  Returns:

  For non-container nodes returns 0; for arrays number of contained elements, and for objects number of fields.

  Since:

  2.2

• isValueNode

  boolean isValueNode()

  Method that returns true for all value nodes: ones that are not containers, and that do not represent "missing" nodes in the path. Such value nodes represent String, Number, Boolean and null values from JSON.

  Note: one and only one of methods isValueNode(), isContainerNode() and isMissingNode() ever returns true for any given node.

  Returns:

  True if this node is considered a value node; something that represents either a scalar value or explicit null

  Since:

  2.2

• isContainerNode

  boolean isContainerNode()

  Method that returns true for container nodes: Arrays and Objects.

  Note: one and only one of methods isValueNode(), isContainerNode() and isMissingNode() ever returns true for any given node.

  Returns:

  True for Array and Object nodes, false otherwise

  Since:

  2.2

• isMissingNode

  boolean isMissingNode()

  Method that returns true for "virtual" nodes which represent missing entries constructed by path accessor methods when there is no actual node matching given criteria.

  Note: one and only one of methods isValueNode(), isContainerNode() and isMissingNode() ever returns true for any given node.

  Returns:

  True if this node represents a "missing" node

  Since:

  2.2

• isArray

  boolean isArray()

  Method that returns true if this node is an Array node, false otherwise. Note that if true is returned, isContainerNode() must also return true.

  Returns:

  True for Array nodes, false for everything else

  Since:

  2.2

• isObject

  boolean isObject()

  Method that returns true if this node is an Object node, false otherwise. Note that if true is returned, isContainerNode() must also return true.

  Returns:

  True for Object nodes, false for everything else

  Since:

  2.2

• get

  TreeNode get(String fieldName)

  Method for accessing value of the specified field of an object node. If this node is not an object (or it does not have a value for specified field name), or if there is no field with such name, null is returned.

  NOTE: handling of explicit null values may vary between implementations; some trees may retain explicit nulls, others not.

  Parameters:

  fieldName - Name of the field (of Object node) to access

  Returns:

  Node that represent value of the specified field, if this node is an Object and has value for the specified field; null otherwise.

  Since:

  2.2

• get

  TreeNode get(int index)

  Method for accessing value of the specified element of an array node. For other nodes, null is returned.

  For array nodes, index specifies exact location within array and allows for efficient iteration over child elements (underlying storage is guaranteed to be efficiently indexable, i.e. has random-access to elements). If index is less than 0, or equal-or-greater than node.size(), null is returned; no exception is thrown for any index.

  Parameters:

  index - Index of the Array node element to access

  Returns:

  Node that represent value of the specified element, if this node is an array and has specified element; null otherwise.

  Since:

  2.2

• path

  TreeNode path(String fieldName)

  Method for accessing value of the specified field of an object node. For other nodes, a "missing node" (virtual node for which isMissingNode() returns true) is returned.

  Parameters:

  fieldName - Name of the field (of Object node) to access

  Returns:

  Node that represent value of the specified field, if this node is an object and has value for the specified field; otherwise "missing node" is returned.

  Since:

  2.2

• path

  TreeNode path(int index)

  Method for accessing value of the specified element of an array node. For other nodes, a "missing node" (virtual node for which isMissingNode() returns true) is returned.

  For array nodes, index specifies exact location within array and allows for efficient iteration over child elements (underlying storage is guaranteed to be efficiently indexable, i.e. has random-access to elements). If index is less than 0, or equal-or-greater than node.size(), "missing node" is returned; no exception is thrown for any index.

  Parameters:

  index - Index of the Array node element to access

  Returns:

  Node that represent value of the specified element, if this node is an array and has specified element; otherwise "missing node" is returned.

  Since:

  2.2

• fieldNames

  Iterator<String> fieldNames()

  Method for accessing names of all fields for this node, iff this node is an Object node. Number of field names accessible will be size().

  Returns:

  An iterator for traversing names of all fields this Object node has (if Object node); empty Iterator otherwise (never null).

  Since:

  2.2

• at

  TreeNode at(JsonPointer ptr)

  Method for locating node specified by given JSON pointer instances. Method will never return null; if no matching node exists, will return a node for which isMissingNode() returns true.

  Parameters:

  ptr - JsonPointer expression for descendant node to return

  Returns:

  Node that matches given JSON Pointer, if any: if no match exists, will return a "missing" node (for which isMissingNode() returns true).

  Since:

  2.3

• at

  TreeNode at(String jsonPointerExpression) throws IllegalArgumentException

  Convenience method that is functionally equivalent to:

     return at(JsonPointer.valueOf(jsonPointerExpression));
  

  Note that if the same expression is used often, it is preferable to construct JsonPointer instance once and reuse it: this method will not perform any caching of compiled expressions.

  Parameters:

  jsonPointerExpression - Expression to compile as a JsonPointer instance

  Returns:

  Node that matches given JSON Pointer, if any: if no match exists, will return a "missing" node (for which isMissingNode() returns true).

  Throws:

  IllegalArgumentException

  Since:

  2.3

• traverse

  JsonParser traverse()

  Method for constructing a JsonParser instance for iterating over contents of the tree that this node is root of. Functionally equivalent to first serializing tree using ObjectCodec and then re-parsing but more efficient.

  NOTE: constructed parser instance will NOT initially point to a token, so before passing it to deserializers, it is typically necessary to advance it to the first available token by calling JsonParser.nextToken().

  Also note that calling this method will NOT pass ObjectCodec reference, so data-binding callback methods like JsonParser.readValueAs(Class) will not work with calling JsonParser.setCodec(com.fasterxml.jackson.core.ObjectCodec)). It is often better to call traverse(ObjectCodec) to pass the codec explicitly.

  Returns:

  JsonParser that will stream over contents of this node

• traverse

  JsonParser traverse(ObjectCodec codec)

  Same as traverse(), but additionally passes ObjectCodec to use if JsonParser.readValueAs(Class) is used (otherwise caller must call JsonParser.setCodec(com.fasterxml.jackson.core.ObjectCodec) on response explicitly).

  NOTE: constructed parser instance will NOT initially point to a token, so before passing it to deserializers, it is typically necessary to advance it to the first available token by calling JsonParser.nextToken().

  Parameters:

  codec - ObjectCodec to associate with parser constructed

  Returns:

  JsonParser that will stream over contents of this node

  Since:

  2.1