Class JsonFactory

  • All Implemented Interfaces:
    Versioned
    Direct Known Subclasses:
    MappingJsonFactory

    public class JsonFactory
    extends Object
    implements Versioned
    The main factory class of Jackson package, used to configure and construct reader (aka parser, JsonParser) and writer (aka generator, JsonGenerator) instances.

    Factory instances are thread-safe and reusable after configuration (if any). Typically applications and services use only a single globally shared factory instance, unless they need differently configured factories. Factory reuse is important if efficiency matters; most recycling of expensive construct is done on per-factory basis.

    Creation of a factory instance is a light-weight operation, and since there is no need for pluggable alternative implementations (as there is no "standard" JSON processor API to implement), the default constructor is used for constructing factory instances.

    Author:
    Tatu Saloranta
    • Field Detail

      • _rootCharSymbols

        protected CharsToNameCanonicalizer _rootCharSymbols
        Each factory comes equipped with a shared root symbol table. It should not be linked back to the original blueprint, to avoid contents from leaking between factories.
      • _rootByteSymbols

        protected BytesToNameCanonicalizer _rootByteSymbols
        Alternative to the basic symbol table, some stream-based parsers use different name canonicalization method.

        TODO: should clean up this; looks messy having 2 alternatives with not very clear differences.

      • _objectCodec

        protected ObjectCodec _objectCodec
        Object that implements conversion functionality between Java objects and JSON content. For base JsonFactory implementation usually not set by default, but can be explicitly set. Sub-classes (like @link org.codehaus.jackson.map.MappingJsonFactory} usually provide an implementation.
      • _parserFeatures

        protected int _parserFeatures
        Currently enabled parser features.
      • _generatorFeatures

        protected int _generatorFeatures
        Currently enabled generator features.
      • _characterEscapes

        protected CharacterEscapes _characterEscapes
        Definition of custom character escapes to use for generators created by this factory, if any. If null, standard data format specific escapes are used.
        Since:
        1.8
      • _inputDecorator

        protected InputDecorator _inputDecorator
        Optional helper object that may decorate input sources, to do additional processing on input during parsing.
        Since:
        1.8
      • _outputDecorator

        protected OutputDecorator _outputDecorator
        Optional helper object that may decorate output object, to do additional processing on output during content generation.
        Since:
        1.8
    • Constructor Detail

      • JsonFactory

        public JsonFactory()
        Default constructor used to create factory instances. Creation of a factory instance is a light-weight operation, but it is still a good idea to reuse limited number of factory instances (and quite often just a single instance): factories are used as context for storing some reused processing objects (such as symbol tables parsers use) and this reuse only works within context of a single factory instance.
    • Method Detail

      • getFormatName

        public String getFormatName()
        Method that returns short textual id identifying format this factory supports.

        Note: sub-classes should override this method; default implementation will return null for all sub-classes

        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
      • isEnabled

        public final boolean isEnabled​(JsonParser.Feature f)
        Checked whether specified parser feature is enabled.
        Since:
        1.2
      • getInputDecorator

        public InputDecorator getInputDecorator()
        Method for getting currently configured input decorator (if any; there is no default decorator).
        Since:
        1.8
      • setInputDecorator

        public JsonFactory setInputDecorator​(InputDecorator d)
        Method for overriding currently configured input decorator
        Since:
        1.8
      • isEnabled

        public final boolean isEnabled​(JsonGenerator.Feature f)
        Check whether specified generator feature is enabled.
        Since:
        1.2
      • getCharacterEscapes

        public CharacterEscapes getCharacterEscapes()
        Method for accessing custom escapes factory uses for JsonGenerators it creates.
        Since:
        1.8
      • getOutputDecorator

        public OutputDecorator getOutputDecorator()
        Method for getting currently configured output decorator (if any; there is no default decorator).
        Since:
        1.8
      • setOutputDecorator

        public JsonFactory setOutputDecorator​(OutputDecorator d)
        Method for overriding currently configured output decorator
        Since:
        1.8
      • createJsonParser

        public JsonParser createJsonParser​(File f)
                                    throws IOException,
                                           JsonParseException
        Method for constructing JSON parser instance to parse contents of specified file. Encoding is auto-detected from contents according to JSON specification recommended mechanism.

        Underlying input stream (needed for reading contents) will be owned (and managed, i.e. closed as need be) by the parser, since caller has no access to it.

        Parameters:
        f - File that contains JSON content to parse
        Throws:
        IOException
        JsonParseException
      • createJsonParser

        public JsonParser createJsonParser​(URL url)
                                    throws IOException,
                                           JsonParseException
        Method for constructing JSON parser instance to parse contents of resource reference by given URL. Encoding is auto-detected from contents according to JSON specification recommended mechanism.

        Underlying input stream (needed for reading contents) will be owned (and managed, i.e. closed as need be) by the parser, since caller has no access to it.

        Parameters:
        url - URL pointing to resource that contains JSON content to parse
        Throws:
        IOException
        JsonParseException
      • createJsonParser

        public JsonParser createJsonParser​(InputStream in)
                                    throws IOException,
                                           JsonParseException
        Method for constructing JSON parser instance to parse the contents accessed via specified input stream.

        The input stream will not be owned by the parser, it will still be managed (i.e. closed if end-of-stream is reacher, or parser close method called) if (and only if) JsonParser.Feature.AUTO_CLOSE_SOURCE is enabled.

        Note: no encoding argument is taken since it can always be auto-detected as suggested by Json RFC.

        Parameters:
        in - InputStream to use for reading JSON content to parse
        Throws:
        IOException
        JsonParseException
      • createJsonParser

        public JsonParser createJsonParser​(byte[] data,
                                           int offset,
                                           int len)
                                    throws IOException,
                                           JsonParseException
        Method for constructing parser for parsing the contents of given byte array.
        Parameters:
        data - Buffer that contains data to parse
        offset - Offset of the first data byte within buffer
        len - Length of contents to parse within buffer
        Throws:
        IOException
        JsonParseException
      • createJsonGenerator

        public JsonGenerator createJsonGenerator​(OutputStream out,
                                                 JsonEncoding enc)
                                          throws IOException
        Method for constructing JSON generator for writing JSON content using specified output stream. Encoding to use must be specified, and needs to be one of available types (as per JSON specification).

        Underlying stream is NOT owned by the generator constructed, so that generator will NOT close the output stream when JsonGenerator.close() is called (unless auto-closing feature, JsonGenerator.Feature.AUTO_CLOSE_TARGET is enabled). Using application needs to close it explicitly if this is the case.

        Note: there are formats that use fixed encoding (like most binary data formats) and that ignore passed in encoding.

        Parameters:
        out - OutputStream to use for writing JSON content
        enc - Character encoding to use
        Throws:
        IOException
      • createJsonGenerator

        public JsonGenerator createJsonGenerator​(Writer out)
                                          throws IOException
        Method for constructing JSON generator for writing JSON content using specified Writer.

        Underlying stream is NOT owned by the generator constructed, so that generator will NOT close the Reader when JsonGenerator.close() is called (unless auto-closing feature, JsonGenerator.Feature.AUTO_CLOSE_TARGET is enabled). Using application needs to close it explicitly.

        Parameters:
        out - Writer to use for writing JSON content
        Throws:
        IOException
      • createJsonGenerator

        public JsonGenerator createJsonGenerator​(OutputStream out)
                                          throws IOException
        Convenience method for constructing generator that uses default encoding of the format (UTF-8 for JSON and most other data formats).

        Note: there are formats that use fixed encoding (like most binary data formats).

        Throws:
        IOException
        Since:
        1.8
      • createJsonGenerator

        public JsonGenerator createJsonGenerator​(File f,
                                                 JsonEncoding enc)
                                          throws IOException
        Method for constructing JSON generator for writing JSON content to specified file, overwriting contents it might have (or creating it if such file does not yet exist). Encoding to use must be specified, and needs to be one of available types (as per JSON specification).

        Underlying stream is owned by the generator constructed, i.e. generator will handle closing of file when JsonGenerator.close() is called.

        Parameters:
        f - File to write contents to
        enc - Character encoding to use
        Throws:
        IOException
      • _createJsonParser

        protected JsonParser _createJsonParser​(InputStream in,
                                               IOContext ctxt)
                                        throws IOException,
                                               JsonParseException
        Overridable factory method that actually instantiates desired parser given InputStream and context object.

        This method is specifically designed to remain compatible between minor versions so that sub-classes can count on it being called as expected. That is, it is part of official interface from sub-class perspective, although not a public method available to users of factory implementations.

        Throws:
        IOException
        JsonParseException
      • _createJsonParser

        protected JsonParser _createJsonParser​(Reader r,
                                               IOContext ctxt)
                                        throws IOException,
                                               JsonParseException
        Overridable factory method that actually instantiates parser using given Reader object for reading content.

        This method is specifically designed to remain compatible between minor versions so that sub-classes can count on it being called as expected. That is, it is part of official interface from sub-class perspective, although not a public method available to users of factory implementations.

        Throws:
        IOException
        JsonParseException
      • _createJsonParser

        protected JsonParser _createJsonParser​(byte[] data,
                                               int offset,
                                               int len,
                                               IOContext ctxt)
                                        throws IOException,
                                               JsonParseException
        Overridable factory method that actually instantiates parser using given Reader object for reading content passed as raw byte array.

        This method is specifically designed to remain compatible between minor versions so that sub-classes can count on it being called as expected. That is, it is part of official interface from sub-class perspective, although not a public method available to users of factory implementations.

        Throws:
        IOException
        JsonParseException
      • _createJsonGenerator

        protected JsonGenerator _createJsonGenerator​(Writer out,
                                                     IOContext ctxt)
                                              throws IOException
        Overridable factory method that actually instantiates generator for given Writer and context object.

        This method is specifically designed to remain compatible between minor versions so that sub-classes can count on it being called as expected. That is, it is part of official interface from sub-class perspective, although not a public method available to users of factory implementations.

        Throws:
        IOException
      • _createUTF8JsonGenerator

        protected JsonGenerator _createUTF8JsonGenerator​(OutputStream out,
                                                         IOContext ctxt)
                                                  throws IOException
        Overridable factory method that actually instantiates generator for given OutputStream and context object, using UTF-8 encoding.

        This method is specifically designed to remain compatible between minor versions so that sub-classes can count on it being called as expected. That is, it is part of official interface from sub-class perspective, although not a public method available to users of factory implementations.

        Throws:
        IOException
      • _createContext

        protected IOContext _createContext​(Object srcRef,
                                           boolean resourceManaged)
        Overridable factory method that actually instantiates desired context object.
      • _getBufferRecycler

        public BufferRecycler _getBufferRecycler()
        Method used by factory to create buffer recycler instances for parsers and generators.

        Note: only public to give access for ObjectMapper

      • _optimizedStreamFromURL

        protected InputStream _optimizedStreamFromURL​(URL url)
                                               throws IOException
        Helper methods used for constructing an optimal stream for parsers to use, when input is to be read from an URL. This helps when reading file content via URL.
        Throws:
        IOException