Package org.codehaus.jackson

Class JsonParser

    • Field Detail

      • _features

        protected int _features
        Bit flag composed of bits that indicate which JsonParser.Features are enabled.

      • _currToken

        protected JsonToken _currToken
        Last token retrieved via nextToken(), if any. Null before the first call to nextToken(), as well as if token has been explicitly cleared (by call to clearCurrentToken())

      • _lastClearedToken

        protected JsonToken _lastClearedToken
        Last cleared token, if any: that is, value that was in effect when clearCurrentToken() was called.

    • Constructor Detail

      • JsonParser

        protected JsonParser()

      • JsonParser

        protected JsonParser​(int features)

    • Method Detail

      • setCodec

        public abstract void setCodec​(ObjectCodec c)
        Setter that allows defining ObjectCodec associated with this parser, if any. Codec is used by readValueAs(Class) method (and its variants).
        Since:
        1.3

      • setSchema

        public void setSchema​(FormatSchema schema)
        Method to call to make this parser use specified schema. Method must be called before trying to parse any content, right after parser instance has been created. Note that not all parsers support schemas; and those that do usually only accept specific types of schemas: ones defined for data format parser can read.

        If parser does not support specified schema, UnsupportedOperationException is thrown.

        Parameters:
        schema - Schema to use
        Throws:
        UnsupportedOperationException - if parser does not support schema
        Since:
        1.8

      • canUseSchema

        public boolean canUseSchema​(FormatSchema schema)
        Method that can be used to verify that given schema can be used with this parser (using setSchema(org.codehaus.jackson.FormatSchema)).
        Parameters:
        schema - Schema to check
        Returns:
        True if this parser can use given schema; false if not
        Since:
        1.8

      • version

        public Version version()
        Description copied from interface: Versioned
        Method called to detect version of the component that implements this interface; returned version should never be null, but may return specific "not available" instance (see Version for details).
        Specified by:
        version in interface Versioned
        Since:
        1.6

      • getInputSource

        public Object getInputSource()
        Method that can be used to get access to object that is used to access input being parsed; this is usually either InputStream or Reader, depending on what parser was constructed with. Note that returned value may be null in some cases; including case where parser implementation does not want to exposed raw source to caller. In cases where input has been decorated, object returned here is the decorated version; this allows some level of interaction between users of parser and decorator object.

        In general use of this accessor should be considered as "last effort", i.e. only used if no other mechanism is applicable.

        Since:
        1.8

      • close

        public abstract void close()
                    throws IOException
        Closes the parser so that no further iteration or data access can be made; will also close the underlying input source if parser either owns the input source, or feature JsonParser.Feature.AUTO_CLOSE_SOURCE is enabled. Whether parser owns the input source depends on factory method that was used to construct instance (so check JsonFactory for details, but the general idea is that if caller passes in closable resource (such as InputStream or Reader) parser does NOT own the source; but if it passes a reference (such as File or URL and creates stream or reader it does own them.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Throws:
        IOException

      • releaseBuffered

        public int releaseBuffered​(OutputStream out)
                    throws IOException
        Method that can be called to push back any content that has been read but not consumed by the parser. This is usually done after reading all content of interest using parser. Content is released by writing it to given stream if possible; if underlying input is byte-based it can released, if not (char-based) it can not.
        Returns:
        -1 if the underlying content source is not byte based (that is, input can not be sent to OutputStream; otherwise number of bytes released (0 if there was nothing to release)
        Throws:
        IOException - if write to stream threw exception
        Since:
        1.6

      • releaseBuffered

        public int releaseBuffered​(Writer w)
                    throws IOException
        Method that can be called to push back any content that has been read but not consumed by the parser. This is usually done after reading all content of interest using parser. Content is released by writing it to given writer if possible; if underlying input is char-based it can released, if not (byte-based) it can not.
        Returns:
        -1 if the underlying content source is not char-based (that is, input can not be sent to Writer; otherwise number of chars released (0 if there was nothing to release)
        Throws:
        IOException - if write using Writer threw exception
        Since:
        1.6

      • nextToken

        public abstract JsonToken nextToken()
                             throws IOException,
                                    JsonParseException
        Main iteration method, which will advance stream enough to determine type of the next token, if any. If none remaining (stream has no content other than possible white space before ending), null will be returned.
        Returns:
        Next token from the stream, if any found, or null to indicate end-of-input
        Throws:
        IOException
        JsonParseException

      • nextValue

        public JsonToken nextValue()
                    throws IOException,
                           JsonParseException
        Iteration method that will advance stream enough to determine type of the next token that is a value type (including JSON Array and Object start/end markers). Or put another way, nextToken() will be called once, and if JsonToken.FIELD_NAME is returned, another time to get the value for the field. Method is most useful for iterating over value entries of JSON objects; field name will still be available by calling getCurrentName() when parser points to the value.
        Returns:
        Next non-field-name token from the stream, if any found, or null to indicate end-of-input (or, for non-blocking parsers, JsonToken.NOT_AVAILABLE if no tokens were available yet)
        Throws:
        IOException
        JsonParseException

      • nextFieldName

        public boolean nextFieldName​(SerializableString str)
                      throws IOException,
                             JsonParseException
        Method that fetches next token (as if calling nextToken()) and verifies whether it is JsonToken.FIELD_NAME with specified name and returns result of that comparison. It is functionally equivalent to: 
          return (nextToken() == JsonToken.FIELD_NAME) && str.getValue().equals(getCurrentName());
        but may be faster for parser to verify, and can therefore be used if caller expects to get such a property name from input next.
        Parameters:
        str - Property name to compare next token to (if next token is JsonToken.FIELD_NAME)
        Throws:
        IOException
        JsonParseException
        Since:
        1.9

      • nextTextValue

        public String nextTextValue()
                     throws IOException,
                            JsonParseException
        Method that fetches next token (as if calling nextToken()) and if it is JsonToken.VALUE_STRING returns contained String value; otherwise returns null. It is functionally equivalent to: 
          return (nextToken() == JsonToken.VALUE_STRING) ? getText() : null;
        but may be faster for parser to process, and can therefore be used if caller expects to get a String value next from input.
        Throws:
        IOException
        JsonParseException
        Since:
        1.9

      • nextIntValue

        public int nextIntValue​(int defaultValue)
                 throws IOException,
                        JsonParseException
        Method that fetches next token (as if calling nextToken()) and if it is JsonToken.VALUE_NUMBER_INT returns 32-bit int value; otherwise returns specified default value It is functionally equivalent to: 
          return (nextToken() == JsonToken.VALUE_NUMBER_INT) ? getIntValue() : defaultValue;
        but may be faster for parser to process, and can therefore be used if caller expects to get a String value next from input.
        Throws:
        IOException
        JsonParseException
        Since:
        1.9

      • nextLongValue

        public long nextLongValue​(long defaultValue)
                   throws IOException,
                          JsonParseException
        Method that fetches next token (as if calling nextToken()) and if it is JsonToken.VALUE_NUMBER_INT returns 64-bit long value; otherwise returns specified default value It is functionally equivalent to: 
          return (nextToken() == JsonToken.VALUE_NUMBER_INT) ? getLongValue() : defaultValue;
        but may be faster for parser to process, and can therefore be used if caller expects to get a String value next from input.
        Throws:
        IOException
        JsonParseException
        Since:
        1.9

      • nextBooleanValue

        public Boolean nextBooleanValue()
                         throws IOException,
                                JsonParseException
        Method that fetches next token (as if calling nextToken()) and if it is JsonToken.VALUE_TRUE or JsonToken.VALUE_FALSE returns matching Boolean value; otherwise return null. It is functionally equivalent to: 
          JsonToken t = nextToken();
  if (t == JsonToken.VALUE_TRUE) return Boolean.TRUE;
  if (t == JsonToken.VALUE_FALSE) return Boolean.FALSE;
  return null;
        but may be faster for parser to process, and can therefore be used if caller expects to get a String value next from input.
        Throws:
        IOException
        JsonParseException
        Since:
        1.9

      • isClosed

        public abstract boolean isClosed()
        Method that can be called to determine whether this parser is closed or not. If it is closed, no new tokens can be retrieved by calling nextToken() (and the underlying stream may be closed). Closing may be due to an explicit call to close() or because parser has encountered end of input.

      • getCurrentToken

        public JsonToken getCurrentToken()
        Accessor to find which token parser currently points to, if any; null will be returned if none. If return value is non-null, data associated with the token is available via other accessor methods.
        Returns:
        Type of the token this parser currently points to, if any: null before any tokens have been read, and after end-of-input has been encountered, as well as if the current token has been explicitly cleared.

      • hasCurrentToken

        public boolean hasCurrentToken()
        Method for checking whether parser currently points to a token (and data for that token is available). Equivalent to check for parser.getCurrentToken() != null.
        Returns:
        True if the parser just returned a valid token via nextToken(); false otherwise (parser was just constructed, encountered end-of-input and returned null from nextToken(), or the token has been consumed)

      • clearCurrentToken

        public void clearCurrentToken()
        Method called to "consume" the current token by effectively removing it so that hasCurrentToken() returns false, and getCurrentToken() null). Cleared token value can still be accessed by calling getLastClearedToken() (if absolutely needed), but usually isn't.

        Method was added to be used by the optional data binder, since it has to be able to consume last token used for binding (so that it will not be used again).

      • getParsingContext

        public abstract JsonStreamContext getParsingContext()
        Method that can be used to access current parsing context reader is in. There are 3 different types: root, array and object contexts, with slightly different available information. Contexts are hierarchically nested, and can be used for example for figuring out part of the input document that correspond to specific array or object (for highlighting purposes, or error reporting). Contexts can also be used for simple xpath-like matching of input, if so desired.

      • getTokenLocation

        public abstract JsonLocation getTokenLocation()
        Method that return the starting location of the current token; that is, position of the first character from input that starts the current token.

      • getCurrentLocation

        public abstract JsonLocation getCurrentLocation()
        Method that returns location of the last processed character; usually for error reporting purposes.

      • getLastClearedToken

        public JsonToken getLastClearedToken()
        Method that can be called to get the last token that was cleared using clearCurrentToken(). This is not necessarily the latest token read. Will return null if no tokens have been cleared, or if parser has been closed.

      • isExpectedStartArrayToken

        public boolean isExpectedStartArrayToken()
        Specialized accessor that can be used to verify that the current token indicates start array (usually meaning that current token is JsonToken.START_ARRAY) when start array is expected. For some specialized parsers this can return true for other cases as well; this is usually done to emulate arrays.

        Default implementation is equivalent to: 

           getCurrentToken() == JsonToken.START_ARRAY
        but may be overridden by custom parser implementations.
        Returns:
        True if the current token can be considered as a start-array marker (such JsonToken.START_ARRAY); false if not.
        Since:
        1.7

      • getTextCharacters

        public abstract char[] getTextCharacters()
                                  throws IOException,
                                         JsonParseException
        Method similar to getText(), but that will return underlying (unmodifiable) character array that contains textual value, instead of constructing a String object to contain this information. Note, however, that:
        • Textual contents are not guaranteed to start at index 0 (rather, call getTextOffset()) to know the actual offset
        • Length of textual contents may be less than the length of returned buffer: call getTextLength() for actual length of returned content.

        Note that caller MUST NOT modify the returned character array in any way -- doing so may corrupt current parser state and render parser instance useless.

        The only reason to call this method (over getText()) is to avoid construction of a String object (which will make a copy of contents).

        Throws:
        IOException
        JsonParseException

      • hasTextCharacters

        public boolean hasTextCharacters()
        Method that can be used to determine whether calling of getTextCharacters() would be the most efficient way to access textual content for the event parser currently points to.

        Default implementation simply returns false since only actual implementation class has knowledge of its internal buffering state. Implementations are strongly encouraged to properly override this method, to allow efficient copying of content by other code.

        Returns:
        True if parser currently has character array that can be efficiently returned via getTextCharacters(); false means that it may or may not exist
        Since:
        1.6

      • getNumberValue

        public abstract Number getNumberValue()
                               throws IOException,
                                      JsonParseException
        Generic number value accessor method that will work for all kinds of numeric values. It will return the optimal (simplest/smallest possible) wrapper object that can express the numeric value just parsed.
        Throws:
        IOException
        JsonParseException

      • getBinaryValue

        public abstract byte[] getBinaryValue​(Base64Variant b64variant)
                               throws IOException,
                                      JsonParseException
        Method that can be used to read (and consume -- results may not be accessible using other methods after the call) base64-encoded binary data included in the current textual JSON value. It works similar to getting String value via getText() and decoding result (except for decoding part), but should be significantly more performant.

        Note that non-decoded textual contents of the current token are not guaranteed to be accessible after this method is called. Current implementation, for example, clears up textual content during decoding. Decoded binary content, however, will be retained until parser is advanced to the next event.

        Parameters:
        b64variant - Expected variant of base64 encoded content (see Base64Variants for definitions of "standard" variants).
        Returns:
        Decoded binary data
        Throws:
        IOException
        JsonParseException

      • getValueAsInt

        public int getValueAsInt()
                  throws IOException,
                         JsonParseException
        Method that will try to convert value of current token to a 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 can not be converted to an int (including structured type markers like start/end Object/Array) default value of 0 will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.6

      • getValueAsInt

        public int getValueAsInt​(int defaultValue)
                  throws IOException,
                         JsonParseException
        Method that will try to convert value of current token to a 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 can not be converted to an int (including structured type markers like start/end Object/Array) specified defaultValue will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.6

      • getValueAsLong

        public long getValueAsLong()
                    throws IOException,
                           JsonParseException
        Method that will try to convert value of current token to a 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 can not be converted to an int (including structured type markers like start/end Object/Array) default value of 0 will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.6

      • getValueAsLong

        public long getValueAsLong​(long defaultValue)
                    throws IOException,
                           JsonParseException
        Method that will try to convert value of current token to a 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 can not be converted to an int (including structured type markers like start/end Object/Array) specified defaultValue will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.6

      • getValueAsDouble

        public double getValueAsDouble()
                        throws IOException,
                               JsonParseException
        Method that will try to convert value of current token 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 can not be converted to an int (including structured types like Objects and Arrays), default value of 0.0 will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.6

      • getValueAsDouble

        public double getValueAsDouble​(double defaultValue)
                        throws IOException,
                               JsonParseException
        Method that will try to convert value of current token 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 can not be converted to an int (including structured types like Objects and Arrays), specified defaultValue will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.6

      • getValueAsBoolean

        public boolean getValueAsBoolean()
                          throws IOException,
                                 JsonParseException
        Method that will try to convert value of current token to a 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 can not be converted to a boolean value (including structured types like Objects and Arrays), default value of false will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.7

      • getValueAsBoolean

        public boolean getValueAsBoolean​(boolean defaultValue)
                          throws IOException,
                                 JsonParseException
        Method that will try to convert value of current token to a 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 can not be converted to a boolean value (including structured types like Objects and Arrays), specified defaultValue will be returned; no exceptions are thrown.

        Throws:
        IOException
        JsonParseException
        Since:
        1.7

      • readValueAs

        public <T> T readValueAs​(Class<T> valueType)
                  throws IOException,
                         JsonProcessingException
        Method to deserialize JSON content into a non-container type (it can be an array type, however): typically a bean, array or a wrapper type (like Boolean). Note: method can only be called if the parser has an object codec assigned; this is true for parsers constructed by MappingJsonFactory but not for JsonFactory (unless its setCodec method has been explicitly called).

        This method may advance the event stream, for structured types the current token will be the closing end marker (END_ARRAY, END_OBJECT) of the bound structure. For non-structured Json types (and for JsonToken.VALUE_EMBEDDED_OBJECT) stream is not advanced.

        Note: this method should NOT be used if the result type is a container (Collection or Map. The reason is that due to type erasure, key and value types can not be introspected when using this method.

        Throws:
        IOException
        JsonProcessingException

      • readValueAs

        public <T> T readValueAs​(TypeReference<?> valueTypeRef)
                  throws IOException,
                         JsonProcessingException
        Method to deserialize JSON content into a Java type, reference to which is passed as argument. Type is passed using so-called "super type token" and specifically needs to be used if the root type is a parameterized (generic) container type. Note: method can only be called if the parser has an object codec assigned; this is true for parsers constructed by MappingJsonFactory but not for JsonFactory (unless its setCodec method has been explicitly called).

        This method may advance the event stream, for structured types the current token will be the closing end marker (END_ARRAY, END_OBJECT) of the bound structure. For non-structured Json types (and for JsonToken.VALUE_EMBEDDED_OBJECT) stream is not advanced.

        Throws:
        IOException
        JsonProcessingException