com.fasterxml.jackson.databind

Class JsonNode

  • All Implemented Interfaces:
    TreeNode, JsonSerializable, Iterable<JsonNode>
    Direct Known Subclasses:
    BaseJsonNode


    public abstract class JsonNodeextends JsonSerializable.Baseimplements TreeNode, Iterable<JsonNode>
    Base class for all JSON nodes, which form the basis of JSON Tree Model that Jackson implements. One way to think of these nodes is to consider them similar to DOM nodes in XML DOM trees.

    As a general design rule, most accessors ("getters") are included in this base class, to allow for traversing structure without type casts. Most mutators, however, need to be accessed through specific sub-classes (such as ObjectNode and ArrayNode). This seems sensible because proper type information is generally available when building or modifying trees, but less often when reading a tree (newly built from parsed JSON content).

    Actual concrete sub-classes can be found from package com.fasterxml.jackson.databind.node.

    Note that it is possible to "read" from nodes, using method TreeNode.traverse(ObjectCodec), which will result in a JsonParser being constructed. This can be used for (relatively) efficient conversations between different representations; and it is what core databind uses for methods like ObjectMapper.treeToValue(TreeNode, Class) and ObjectMapper.treeAsTokens(TreeNode)

    • Constructor Summary

      Constructors 
      ModifierConstructor and Description
      protected JsonNode() 
    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and TypeMethod and Description
      protected abstract JsonNode_at(JsonPointer ptr) 
      protected <T> T_reportRequiredViolation(String msgTemplate, Object... args)
      Helper method that throws IllegalArgumentException as a result of violating "required-constraint" for this node (for required(java.lang.String) or related methods).
      protected <T extends JsonNode>
      T
      _this() 
      booleanasBoolean()
      Method that will try to convert value of this node to a Java boolean.
      booleanasBoolean(boolean defaultValue)
      Method that will try to convert value of this node to a Java boolean.
      doubleasDouble()
      Method that will try to convert value of this node to a Java double.
      doubleasDouble(double defaultValue)
      Method that will try to convert value of this node to a Java double.
      intasInt()
      Method that will try to convert value of this node to a Java int.
      intasInt(int defaultValue)
      Method that will try to convert value of this node to a Java int.
      longasLong()
      Method that will try to convert value of this node to a Java long.
      longasLong(long defaultValue)
      Method that will try to convert value of this node to a Java long.
      abstract StringasText()
      Method that will return a valid String representation of the container value, if the node is a value node (method isValueNode() returns true), otherwise empty String.
      StringasText(String defaultValue)
      Method similar to asText(), except that it will return defaultValue in cases where null value would be returned; either for missing nodes (trying to access missing property, or element at invalid item for array) or explicit nulls.
      JsonNodeat(JsonPointer ptr)
      Method for locating node specified by given JSON pointer instances.
      JsonNodeat(String jsonPtrExpr)
      Convenience method that is functionally equivalent to:
      BigIntegerbigIntegerValue()
      Returns integer value for this node (as BigDecimal), if and only if this node is numeric (isNumber() returns true).
      byte[]binaryValue()
      Method to use for accessing binary content of binary nodes (nodes for which isBinary() returns true); or for Text Nodes (ones for which textValue() returns non-null value), to read decoded base64 data.
      booleanbooleanValue()
      Method to use for accessing JSON boolean values (value literals 'true' and 'false').
      booleancanConvertToInt()
      Method that can be used to check whether this node is a numeric node (isNumber() would return true) AND its value fits within Java's 32-bit signed integer type, int.
      booleancanConvertToLong()
      Method that can be used to check whether this node is a numeric node (isNumber() would return true) AND its value fits within Java's 64-bit signed integer type, long.
      BigDecimaldecimalValue()
      Returns floating point value for this node (as BigDecimal), if and only if this node is numeric (isNumber() returns true).
      abstract <T extends JsonNode>
      T
      deepCopy()
      Method that can be called to get a node that is guaranteed not to allow changing of this node through mutators on this node or any of its children.
      doubledoubleValue()
      Returns 64-bit floating point (double) value for this node, if and only if this node is numeric (isNumber() returns true).
      Iterator<JsonNode>elements()
      Method for accessing all value nodes of this Node, iff this node is a JSON Array or Object node.
      booleanequals(Comparator<JsonNode> comparator, JsonNode other)
      Entry method for invoking customizable comparison, using passed-in Comparator object.
      abstract booleanequals(Object o)
      Equality for node objects is defined as full (deep) value equality.
      Iterator<String>fieldNames() 
      Iterator<Map.Entry<String,JsonNode>>fields() 
      abstract JsonNodefindParent(String fieldName)
      Method for finding a JSON Object that contains specified field, within this node or its descendants.
      List<JsonNode>findParents(String fieldName)
      Method for finding a JSON Object that contains specified field, within this node or its descendants.
      abstract List<JsonNode>findParents(String fieldName, List<JsonNode> foundSoFar) 
      abstract JsonNodefindPath(String fieldName)
      Method similar to findValue(java.lang.String), but that will return a "missing node" instead of null if no field is found.
      abstract JsonNodefindValue(String fieldName)
      Method for finding a JSON Object field with specified name in this node or its child nodes, and returning value it has.
      List<JsonNode>findValues(String fieldName)
      Method for finding JSON Object fields with specified name, and returning found ones as a List.
      abstract List<JsonNode>findValues(String fieldName, List<JsonNode> foundSoFar) 
      List<String>findValuesAsText(String fieldName)
      Similar to findValues(java.lang.String), but will additionally convert values into Strings, calling asText().
      abstract List<String>findValuesAsText(String fieldName, List<String> foundSoFar) 
      floatfloatValue()
      Returns 32-bit floating value for this node, if and only if this node is numeric (isNumber() returns true).
      abstract JsonNodeget(int index)
      Method for accessing value of the specified element of an array node.
      JsonNodeget(String fieldName)
      Method for accessing value of the specified field of an object node.
      abstract JsonNodeTypegetNodeType()
      Return the type of this node
      booleanhas(int index)
      Method that allows checking whether this node is JSON Array node and contains a value for specified index If this is the case (including case of specified indexing having null as value), returns true; otherwise returns false.
      booleanhas(String fieldName)
      Method that allows checking whether this node is JSON Object node and contains value for specified property.
      booleanhasNonNull(int index)
      Method that is similar to has(int), but that will return false for explicitly added nulls.
      booleanhasNonNull(String fieldName)
      Method that is similar to has(String), but that will return false for explicitly added nulls.
      intintValue()
      Returns integer value for this node, if and only if this node is numeric (isNumber() returns true).
      booleanisArray() 
      booleanisBigDecimal() 
      booleanisBigInteger() 
      booleanisBinary()
      Method that can be used to check if this node represents binary data (Base64 encoded).
      booleanisBoolean()
      Method that can be used to check if this node was created from JSON boolean value (literals "true" and "false").
      booleanisContainerNode() 
      booleanisDouble() 
      booleanisEmpty()
      Convenience method that is functionally same as:
      booleanisFloat() 
      booleanisFloatingPointNumber() 
      booleanisInt()
      Method that can be used to check whether contained value is a number represented as Java int.
      booleanisIntegralNumber() 
      booleanisLong()
      Method that can be used to check whether contained value is a number represented as Java long.
      booleanisMissingNode() 
      booleanisNull()
      Method that can be used to check if this node was created from JSON literal null value.
      booleanisNumber() 
      booleanisObject() 
      booleanisPojo()
      Method that can be used to check if the node is a wrapper for a POJO ("Plain Old Java Object" aka "bean".
      booleanisShort()
      Method that can be used to check whether contained value is a number represented as Java short.
      booleanisTextual()
      Method that checks whether this node represents basic JSON String value.
      booleanisValueNode() 
      Iterator<JsonNode>iterator()
      Same as calling elements(); implemented so that convenience "for-each" loop can be used for looping over elements of JSON Array constructs.
      longlongValue()
      Returns 64-bit long value for this node, if and only if this node is numeric (isNumber() returns true).
      NumbernumberValue()
      Returns numeric value for this node, if and only if this node is numeric (isNumber() returns true); otherwise returns null
      abstract JsonNodepath(int index)
      This method is similar to get(int), except that instead of returning null if no such element exists (due to index being out of range, or this node not being an array), a "missing node" (node that returns true for isMissingNode()) will be returned.
      abstract JsonNodepath(String fieldName)
      This method is similar to get(String), except that instead of returning null if no such value exists (due to this node not being an object, or object not having value for the specified field), a "missing node" (node that returns true for isMissingNode()) will be returned.
      <T extends JsonNode>
      T
      require()
      Method that may be called to verify that this node is NOT so-called "missing node": that is, one for which isMissingNode() returns true.
      JsonNoderequired(int index)
      Method is functionally equivalent topath(index).required() and can be used to check that this node is an ArrayNode (that is, represents JSON Array value) and has value for specified index (but note that value may be explicit JSON null value).
      JsonNoderequired(String fieldName)
      Method is functionally equivalent topath(fieldName).required() and can be used to check that this node is an ObjectNode (that is, represents JSON Object value) and has value for specified property with key fieldName (but note that value may be explicit JSON null value).
      JsonNoderequiredAt(JsonPointer path)
      Method is functionally equivalent toat(path).required() and can be used to check that there is an actual value node at specified JsonPointer starting from this node (but note that value may be explicit JSON null value).
      JsonNoderequiredAt(String pathExpr)
      Method is functionally equivalent toat(pathExpr).required() and can be used to check that there is an actual value node at specified JsonPointer starting from this node (but note that value may be explicit JSON null value).
      <T extends JsonNode>
      T
      requireNonNull()
      Method that may be called to verify that this node is neither so-called "missing node" (that is, one for which isMissingNode() returns true) nor "null node" (one for which isNull() returns true).
      shortshortValue()
      Returns 16-bit short value for this node, if and only if this node is numeric (isNumber() returns true).
      intsize() 
      StringtextValue()
      Method to use for accessing String values.
      StringtoPrettyString()
      Alternative to toString() that will serialize this node using Jackson default pretty-printer.
      abstract StringtoString()
      Method that will produce (as of Jackson 2.10) valid JSON using default settings of databind, as String.
      <T extends JsonNode>
      T
      with(String propertyName)
      Method that can be called on Object nodes, to access a property that has Object value; or if no such property exists, to create, add and return such Object node.
      <T extends JsonNode>
      T
      withArray(String propertyName)
      Method that can be called on Object nodes, to access a property that has Array value; or if no such property exists, to create, add and return such Array node.
    • Constructor Detail

      • JsonNode

        protected JsonNode()
    • Method Detail

      • deepCopy

        public abstract <T extends JsonNode> T deepCopy()
        Method that can be called to get a node that is guaranteed not to allow changing of this node through mutators on this node or any of its children. This means it can either make a copy of this node (and all mutable children and grand children nodes), or node itself if it is immutable.

        Note: return type is guaranteed to have same type as the node method is called on; which is why method is declared with local generic type.

        Returns:
        Node that is either a copy of this node (and all non-leaf children); or, for immutable leaf nodes, node itself.
        Since:
        2.0
      • size

        public int size()
        Specified by:
        size in interface TreeNode
      • isEmpty

        public boolean isEmpty()
        Convenience method that is functionally same as:
            size() == 0
        for all node types.
        Since:
        2.10
      • isValueNode

        public final boolean isValueNode()
        Specified by:
        isValueNode in interface TreeNode
      • isArray

        public boolean isArray()
        Specified by:
        isArray in interface TreeNode
      • isObject

        public boolean isObject()
        Specified by:
        isObject in interface TreeNode
      • get

        public abstract JsonNode get(int index)
        Method for accessing value of the specified element of an array node. For other nodes, null is always 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.

        NOTE: if the element value has been explicitly set as null (which is different from removal!), a NullNode will be returned, not null.

        Specified by:
        get in interface TreeNode
        Returns:
        Node that represent value of the specified element, if this node is an array and has specified element. Null otherwise.
      • get

        public JsonNode 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: if the property value has been explicitly set as null (which is different from removal!), a NullNode will be returned, not null.

        Specified by:
        get in interface TreeNode
        Returns:
        Node that represent value of the specified field, if this node is an object and has value for the specified field. Null otherwise.
      • path

        public abstract JsonNode path(String fieldName)
        This method is similar to get(String), except that instead of returning null if no such value exists (due to this node not being an object, or object not having value for the specified field), a "missing node" (node that returns true for isMissingNode()) will be returned. This allows for convenient and safe chained access via path calls.
        Specified by:
        path in interface TreeNode
      • path

        public abstract JsonNode path(int index)
        This method is similar to get(int), except that instead of returning null if no such element exists (due to index being out of range, or this node not being an array), a "missing node" (node that returns true for isMissingNode()) will be returned. This allows for convenient and safe chained access via path calls.
        Specified by:
        path in interface TreeNode
      • at

        public final JsonNode 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.
        Specified by:
        at in interface TreeNode
        Returns:
        Node that matches given JSON Pointer: if no match exists, will return a node for which isMissingNode() returns true.
        Since:
        2.3
      • at

        public final JsonNode at(String jsonPtrExpr)
        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.

        Specified by:
        at in interface TreeNode
        Parameters:
        jsonPtrExpr - Expression to compile as a JsonPointer instance
        Returns:
        Node that matches given JSON Pointer: if no match exists, will return a node for which TreeNode.isMissingNode() returns true.
        Since:
        2.3
      • getNodeType

        public abstract JsonNodeType getNodeType()
        Return the type of this node
        Returns:
        the node type as a JsonNodeType enum value
        Since:
        2.2
      • isPojo

        public final boolean isPojo()
        Method that can be used to check if the node is a wrapper for a POJO ("Plain Old Java Object" aka "bean". Returns true only for instances of POJONode.
        Returns:
        True if this node wraps a POJO
      • isNumber

        public final boolean isNumber()
        Returns:
        True if this node represents a numeric JSON value
      • isIntegralNumber

        public boolean isIntegralNumber()
        Returns:
        True if this node represents an integral (integer) numeric JSON value
      • isFloatingPointNumber

        public boolean isFloatingPointNumber()
        Returns:
        True if this node represents a non-integral numeric JSON value
      • isShort

        public boolean isShort()
        Method that can be used to check whether contained value is a number represented as Java short. Note, however, that even if this method returns false, it is possible that conversion would be possible from other numeric types -- to check if this is possible, use canConvertToInt() instead.
        Returns:
        True if the value contained by this node is stored as Java short
      • isInt

        public boolean isInt()
        Method that can be used to check whether contained value is a number represented as Java int. Note, however, that even if this method returns false, it is possible that conversion would be possible from other numeric types -- to check if this is possible, use canConvertToInt() instead.
        Returns:
        True if the value contained by this node is stored as Java int
      • isLong

        public boolean isLong()
        Method that can be used to check whether contained value is a number represented as Java long. Note, however, that even if this method returns false, it is possible that conversion would be possible from other numeric types -- to check if this is possible, use canConvertToLong() instead.
        Returns:
        True if the value contained by this node is stored as Java long
      • isFloat

        public boolean isFloat()
        Since:
        2.2
      • isDouble

        public boolean isDouble()
      • isBigDecimal

        public boolean isBigDecimal()
      • isBigInteger

        public boolean isBigInteger()
      • isTextual

        public final boolean isTextual()
        Method that checks whether this node represents basic JSON String value.
      • isBoolean

        public final boolean isBoolean()
        Method that can be used to check if this node was created from JSON boolean value (literals "true" and "false").
      • isNull

        public final boolean isNull()
        Method that can be used to check if this node was created from JSON literal null value.
      • isBinary

        public final boolean isBinary()
        Method that can be used to check if this node represents binary data (Base64 encoded). Although this will be externally written as JSON String value, isTextual() will return false if this method returns true.
        Returns:
        True if this node represents base64 encoded binary data
      • canConvertToInt

        public boolean canConvertToInt()
        Method that can be used to check whether this node is a numeric node (isNumber() would return true) AND its value fits within Java's 32-bit signed integer type, int. Note that floating-point numbers are convertible if the integral part fits without overflow (as per standard Java coercion rules)

        NOTE: this method does not consider possible value type conversion from JSON String into Number; so even if this method returns false, it is possible that asInt() could still succeed if node is a JSON String representing integral number, or boolean.

        Since:
        2.0
      • canConvertToLong

        public boolean canConvertToLong()
        Method that can be used to check whether this node is a numeric node (isNumber() would return true) AND its value fits within Java's 64-bit signed integer type, long. Note that floating-point numbers are convertible if the integral part fits without overflow (as per standard Java coercion rules)

        NOTE: this method does not consider possible value type conversion from JSON String into Number; so even if this method returns false, it is possible that asLong() could still succeed if node is a JSON String representing integral number, or boolean.

        Since:
        2.0
      • textValue

        public String textValue()
        Method to use for accessing String values. Does NOT do any conversions for non-String value nodes; for non-String values (ones for which isTextual() returns false) null will be returned. For String values, null is never returned (but empty Strings may be)
        Returns:
        Textual value this node contains, iff it is a textual JSON node (comes from JSON String value entry)
      • binaryValue

        public byte[] binaryValue()                   throws IOException
        Method to use for accessing binary content of binary nodes (nodes for which isBinary() returns true); or for Text Nodes (ones for which textValue() returns non-null value), to read decoded base64 data. For other types of nodes, returns null.
        Returns:
        Binary data this node contains, iff it is a binary node; null otherwise
        Throws:
        IOException
      • booleanValue

        public boolean booleanValue()
        Method to use for accessing JSON boolean values (value literals 'true' and 'false'). For other types, always returns false.
        Returns:
        Textual value this node contains, iff it is a textual json node (comes from JSON String value entry)
      • numberValue

        public Number numberValue()
        Returns numeric value for this node, if and only if this node is numeric (isNumber() returns true); otherwise returns null
        Returns:
        Number value this node contains, if any (null for non-number nodes).
      • shortValue

        public short shortValue()
        Returns 16-bit short value for this node, if and only if this node is numeric (isNumber() returns true). For other types returns 0. For floating-point numbers, value is truncated using default Java coercion, similar to how cast from double to short operates.
        Returns:
        Short value this node contains, if any; 0 for non-number nodes.
      • intValue

        public int intValue()
        Returns integer value for this node, if and only if this node is numeric (isNumber() returns true). For other types returns 0. For floating-point numbers, value is truncated using default Java coercion, similar to how cast from double to int operates.
        Returns:
        Integer value this node contains, if any; 0 for non-number nodes.
      • longValue

        public long longValue()
        Returns 64-bit long value for this node, if and only if this node is numeric (isNumber() returns true). For other types returns 0. For floating-point numbers, value is truncated using default Java coercion, similar to how cast from double to long operates.
        Returns:
        Long value this node contains, if any; 0 for non-number nodes.
      • floatValue

        public float floatValue()
        Returns 32-bit floating value for this node, if and only if this node is numeric (isNumber() returns true). For other types returns 0.0. For integer values, conversion is done using coercion; this means that an overflow is possible for `long` values
        Returns:
        32-bit float value this node contains, if any; 0.0 for non-number nodes.
        Since:
        2.2
      • doubleValue

        public double doubleValue()
        Returns 64-bit floating point (double) value for this node, if and only if this node is numeric (isNumber() returns true). For other types returns 0.0. For integer values, conversion is done using coercion; this may result in overflows with BigInteger values.
        Returns:
        64-bit double value this node contains, if any; 0.0 for non-number nodes.
        Since:
        2.2
      • decimalValue

        public BigDecimal decimalValue()
        Returns floating point value for this node (as BigDecimal), if and only if this node is numeric (isNumber() returns true). For other types returns BigDecimal.ZERO.
        Returns:
        BigDecimal value this node contains, if numeric node; BigDecimal.ZERO for non-number nodes.
      • bigIntegerValue

        public BigInteger bigIntegerValue()
        Returns integer value for this node (as BigDecimal), if and only if this node is numeric (isNumber() returns true). For other types returns BigInteger.ZERO.
        Returns:
        BigInteger value this node contains, if numeric node; BigInteger.ZERO for non-number nodes.
      • asText

        public abstract String asText()
        Method that will return a valid String representation of the container value, if the node is a value node (method isValueNode() returns true), otherwise empty String.
      • asText

        public String asText(String defaultValue)
        Method similar to asText(), except that it will return defaultValue in cases where null value would be returned; either for missing nodes (trying to access missing property, or element at invalid item for array) or explicit nulls.
        Since:
        2.4
      • asInt

        public int asInt()
        Method that will try to convert value of this node to a Java int. Numbers are coerced using default Java rules; booleans convert to 0 (false) and 1 (true), and Strings are parsed using default Java language integer parsing rules.

        If representation cannot be converted to an int (including structured types like Objects and Arrays), default value of 0 will be returned; no exceptions are thrown.

      • asInt

        public int asInt(int defaultValue)
        Method that will try to convert value of this node to a Java int. Numbers are coerced using default Java rules; booleans convert to 0 (false) and 1 (true), and Strings are parsed using default Java language integer parsing rules.

        If representation cannot be converted to an int (including structured types like Objects and Arrays), specified defaultValue will be returned; no exceptions are thrown.

      • asLong

        public long asLong()
        Method that will try to convert value of this node to a Java long. Numbers are coerced using default Java rules; booleans convert to 0 (false) and 1 (true), and Strings are parsed using default Java language integer parsing rules.

        If representation cannot be converted to an long (including structured types like Objects and Arrays), default value of 0 will be returned; no exceptions are thrown.

      • asLong

        public long asLong(long defaultValue)
        Method that will try to convert value of this node to a Java long. Numbers are coerced using default Java rules; booleans convert to 0 (false) and 1 (true), and Strings are parsed using default Java language integer parsing rules.

        If representation cannot be converted to an long (including structured types like Objects and Arrays), specified defaultValue will be returned; no exceptions are thrown.

      • asDouble

        public double asDouble()
        Method that will try to convert value of this node to a Java double. Numbers are coerced using default Java rules; booleans convert to 0.0 (false) and 1.0 (true), and Strings are parsed using default Java language integer parsing rules.

        If representation cannot be converted to an int (including structured types like Objects and Arrays), default value of 0.0 will be returned; no exceptions are thrown.

      • asDouble

        public double asDouble(double defaultValue)
        Method that will try to convert value of this node to a Java double. Numbers are coerced using default Java rules; booleans convert to 0.0 (false) and 1.0 (true), and Strings are parsed using default Java language integer parsing rules.

        If representation cannot be converted to an int (including structured types like Objects and Arrays), specified defaultValue will be returned; no exceptions are thrown.

      • asBoolean

        public boolean asBoolean()
        Method that will try to convert value of this node to a Java boolean. JSON booleans map naturally; integer numbers other than 0 map to true, and 0 maps to false and Strings 'true' and 'false' map to corresponding values.

        If representation cannot be converted to a boolean value (including structured types like Objects and Arrays), default value of false will be returned; no exceptions are thrown.

      • asBoolean

        public boolean asBoolean(boolean defaultValue)
        Method that will try to convert value of this node to a Java boolean. JSON booleans map naturally; integer numbers other than 0 map to true, and 0 maps to false and Strings 'true' and 'false' map to corresponding values.

        If representation cannot be converted to a boolean value (including structured types like Objects and Arrays), specified defaultValue will be returned; no exceptions are thrown.

      • requireNonNull

        public <T extends JsonNode> T requireNonNull()                                      throws IllegalArgumentException
        Method that may be called to verify that this node is neither so-called "missing node" (that is, one for which isMissingNode() returns true) nor "null node" (one for which isNull() returns true). If non-null non-missing node, this is returned to allow chaining; otherwise IllegalArgumentException is thrown.
        Returns:
        this node to allow chaining
        Throws:
        IllegalArgumentException - if this node is either "missing node" or "null node"
        Since:
        2.10
      • required

        public JsonNode required(String fieldName)                  throws IllegalArgumentException
        Method is functionally equivalent topath(fieldName).required() and can be used to check that this node is an ObjectNode (that is, represents JSON Object value) and has value for specified property with key fieldName (but note that value may be explicit JSON null value). If this node is Object Node and has value for specified property, this is returned to allow chaining; otherwise IllegalArgumentException is thrown.
        Returns:
        this node to allow chaining
        Throws:
        IllegalArgumentException - if this node is not an Object node or if it does not have value for specified property
        Since:
        2.10
      • required

        public JsonNode required(int index)                  throws IllegalArgumentException
        Method is functionally equivalent topath(index).required() and can be used to check that this node is an ArrayNode (that is, represents JSON Array value) and has value for specified index (but note that value may be explicit JSON null value). If this node is Array Node and has value for specified index, this is returned to allow chaining; otherwise IllegalArgumentException is thrown.
        Returns:
        this node to allow chaining
        Throws:
        IllegalArgumentException - if this node is not an Array node or if it does not have value for specified index
        Since:
        2.10
      • requiredAt

        public JsonNode requiredAt(String pathExpr)                    throws IllegalArgumentException
        Method is functionally equivalent toat(pathExpr).required() and can be used to check that there is an actual value node at specified JsonPointer starting from this node (but note that value may be explicit JSON null value). If such value node exists this is returned to allow chaining; otherwise IllegalArgumentException is thrown.
        Returns:
        this node to allow chaining
        Throws:
        IllegalArgumentException - if no value node exists at given JSON Pointer path
        Since:
        2.10
      • requiredAt

        public final JsonNode requiredAt(JsonPointer path)                          throws IllegalArgumentException
        Method is functionally equivalent toat(path).required() and can be used to check that there is an actual value node at specified JsonPointer starting from this node (but note that value may be explicit JSON null value). If such value node exists this is returned to allow chaining; otherwise IllegalArgumentException is thrown.
        Returns:
        this node to allow chaining
        Throws:
        IllegalArgumentException - if no value node exists at given JSON Pointer path
        Since:
        2.10
      • has

        public boolean has(String fieldName)
        Method that allows checking whether this node is JSON Object node and contains value for specified property. If this is the case (including properties with explicit null values), returns true; otherwise returns false.

        This method is equivalent to:

           node.get(fieldName) != null
        (since return value of get() is node, not value node contains)

        NOTE: when explicit null values are added, this method will return true for such properties.

        Parameters:
        fieldName - Name of element to check
        Returns:
        True if this node is a JSON Object node, and has a property entry with specified name (with any value, including null value)
      • has

        public boolean has(int index)
        Method that allows checking whether this node is JSON Array node and contains a value for specified index If this is the case (including case of specified indexing having null as value), returns true; otherwise returns false.

        Note: array element indexes are 0-based.

        This method is equivalent to:

           node.get(index) != null

        NOTE: this method will return true for explicitly added null values.

        Parameters:
        index - Index to check
        Returns:
        True if this node is a JSON Object node, and has a property entry with specified name (with any value, including null value)
      • hasNonNull

        public boolean hasNonNull(String fieldName)
        Method that is similar to has(String), but that will return false for explicitly added nulls.

        This method is functionally equivalent to:

           node.get(fieldName) != null && !node.get(fieldName).isNull()

        Since:
        2.1
      • hasNonNull

        public boolean hasNonNull(int index)
        Method that is similar to has(int), but that will return false for explicitly added nulls.

        This method is equivalent to:

           node.get(index) != null && !node.get(index).isNull()

        Since:
        2.1
      • elements

        public Iterator<JsonNode> elements()
        Method for accessing all value nodes of this Node, iff this node is a JSON Array or Object node. In case of Object node, field names (keys) are not included, only values. For other types of nodes, returns empty iterator.
      • fields

        public Iterator<Map.Entry<String,JsonNode>> fields()
        Returns:
        Iterator that can be used to traverse all key/value pairs for object nodes; empty iterator (no contents) for other types
      • findValue

        public abstract JsonNode findValue(String fieldName)
        Method for finding a JSON Object field with specified name in this node or its child nodes, and returning value it has. If no matching field is found in this node or its descendants, returns null.
        Parameters:
        fieldName - Name of field to look for
        Returns:
        Value of first matching node found, if any; null if none
      • findValues

        public final List<JsonNode> findValues(String fieldName)
        Method for finding JSON Object fields with specified name, and returning found ones as a List. Note that sub-tree search ends if a field is found, so possible children of result nodes are not included. If no matching fields are found in this node or its descendants, returns an empty List.
        Parameters:
        fieldName - Name of field to look for
      • findPath

        public abstract JsonNode findPath(String fieldName)
        Method similar to findValue(java.lang.String), but that will return a "missing node" instead of null if no field is found. Missing node is a specific kind of node for which isMissingNode() returns true; and all value access methods return empty or missing value.
        Parameters:
        fieldName - Name of field to look for
        Returns:
        Value of first matching node found; or if not found, a "missing node" (non-null instance that has no value)
      • findParent

        public abstract JsonNode findParent(String fieldName)
        Method for finding a JSON Object that contains specified field, within this node or its descendants. If no matching field is found in this node or its descendants, returns null.
        Parameters:
        fieldName - Name of field to look for
        Returns:
        Value of first matching node found, if any; null if none
      • findParents

        public final List<JsonNode> findParents(String fieldName)
        Method for finding a JSON Object that contains specified field, within this node or its descendants. If no matching field is found in this node or its descendants, returns null.
        Parameters:
        fieldName - Name of field to look for
        Returns:
        Value of first matching node found, if any; null if none
      • with

        public <T extends JsonNode> T with(String propertyName)
        Method that can be called on Object nodes, to access a property that has Object value; or if no such property exists, to create, add and return such Object node. If the node method is called on is not Object node, or if property exists and has value that is not Object node, UnsupportedOperationException is thrown

        NOTE: since 2.10 has had co-variant return type

      • withArray

        public <T extends JsonNode> T withArray(String propertyName)
        Method that can be called on Object nodes, to access a property that has Array value; or if no such property exists, to create, add and return such Array node. If the node method is called on is not Object node, or if property exists and has value that is not Array node, UnsupportedOperationException is thrown

        NOTE: since 2.10 has had co-variant return type

      • equals

        public boolean equals(Comparator<JsonNode> comparator,                      JsonNode other)
        Entry method for invoking customizable comparison, using passed-in Comparator object. Nodes will handle traversal of structured types (arrays, objects), but defer to comparator for scalar value comparisons. If a "natural" Comparator is passed -- one that simply calls equals() on one of arguments, passing the other -- implementation is the same as directly calling equals() on node.

        Default implementation simply delegates to passed in comparator, with this as the first argument, and other as the second argument.

        Parameters:
        comparator - Object called to compare two scalar JsonNode instances, and return either 0 (are equals) or non-zero (not equal)
        Since:
        2.6
      • toString

        public abstract String toString()
        Method that will produce (as of Jackson 2.10) valid JSON using default settings of databind, as String. If you want other kinds of JSON output (or output formatted using one of other Jackson-supported data formats) make sure to use ObjectMapper or ObjectWriter to serialize an instance, for example:
           String json = objectMapper.writeValueAsString(rootNode);

        Note: method defined as abstract to ensure all implementation classes explicitly implement method, instead of relying on Object.toString() definition.

        Overrides:
        toString in class Object
      • toPrettyString

        public String toPrettyString()
        Alternative to toString() that will serialize this node using Jackson default pretty-printer.
        Since:
        2.10
      • equals

        public abstract boolean equals(Object o)
        Equality for node objects is defined as full (deep) value equality. This means that it is possible to compare complete JSON trees for equality by comparing equality of root nodes.

        Note: marked as abstract to ensure all implementation classes define it properly and not rely on definition from Object.

        Overrides:
        equals in class Object
      • _this

        protected <T extends JsonNode> T _this()

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