org.codehaus.jackson.JsonFactory Maven / Gradle / Ivy
/* Jackson JSON-processor.
*
* Copyright (c) 2007- Tatu Saloranta, [email protected]
*
* Licensed under the License specified in file LICENSE, included with
* the source code and binary code bundles.
* You may not use this file except in compliance with the License.
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.codehaus.jackson;
import java.io.*;
import java.lang.ref.SoftReference;
import java.net.URL;
import org.codehaus.jackson.io.*;
import org.codehaus.jackson.impl.ByteSourceBootstrapper;
import org.codehaus.jackson.impl.ReaderBasedParser;
import org.codehaus.jackson.impl.WriterBasedGenerator;
import org.codehaus.jackson.sym.BytesToNameCanonicalizer;
import org.codehaus.jackson.sym.CharsToNameCanonicalizer;
import org.codehaus.jackson.util.BufferRecycler;
/**
* The main factory class of Jackson package, used to configure and
* construct reader (aka parser, {@link JsonParser})
* and writer (aka generator, {@link 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
*/
public class JsonFactory
{
/**
* Bitfield (set of flags) of all parser features that are enabled
* by default.
*/
final static int DEFAULT_PARSER_FEATURE_FLAGS = JsonParser.Feature.collectDefaults();
/**
* Bitfield (set of flags) of all generator features that are enabled
* by default.
*/
final static int DEFAULT_GENERATOR_FEATURE_FLAGS = JsonGenerator.Feature.collectDefaults();
/*
/******************************************************
/* Buffer, symbol table management
/******************************************************
*/
/**
* This ThreadLocal contains a {@link SoftRerefence}
* to a {@link BufferRecycler} used to provide a low-cost
* buffer recycling between reader and writer instances.
*/
final static ThreadLocal> _recyclerRef = new ThreadLocal>();
/**
* 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.
*/
protected CharsToNameCanonicalizer _rootCharSymbols = CharsToNameCanonicalizer.createRoot();
/**
* 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.
*/
protected BytesToNameCanonicalizer _rootByteSymbols = BytesToNameCanonicalizer.createRoot();
/*
/******************************************************
/* Configuration
/******************************************************
*/
/**
* 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.
*/
protected ObjectCodec _objectCodec;
protected int _parserFeatures = DEFAULT_PARSER_FEATURE_FLAGS;
protected int _generatorFeatures = DEFAULT_GENERATOR_FEATURE_FLAGS;
/**
* 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.
*/
public JsonFactory() { this(null); }
public JsonFactory(ObjectCodec oc) { _objectCodec = oc; }
/*
/******************************************************
/* Configuration, parser settings
/******************************************************
*/
/**
* Method for enabling or disabling specified parser feature
* (check {@link JsonParser.Feature} for list of features)
*
* @since 1.2
*/
public final JsonFactory configure(JsonParser.Feature f, boolean state)
{
if (state) {
enable(f);
} else {
disable(f);
}
return this;
}
/**
* Method for enabling specified parser feature
* (check {@link JsonParser.Feature} for list of features)
*
* @since 1.2
*/
public JsonFactory enable(JsonParser.Feature f) {
_parserFeatures |= f.getMask();
return this;
}
/**
* Method for disabling specified parser features
* (check {@link JsonParser.Feature} for list of features)
*
* @since 1.2
*/
public JsonFactory disable(JsonParser.Feature f) {
_parserFeatures &= ~f.getMask();
return this;
}
/**
* Checked whether specified parser feature is enabled.
*
* @since 1.2
*/
public final boolean isEnabled(JsonParser.Feature f) {
return (_parserFeatures & f.getMask()) != 0;
}
// // // Older deprecated (as of 1.2) methods
/**
* @deprecated Use {@link #enable(JsonParser.Feature)} instead
*/
public final void enableParserFeature(JsonParser.Feature f) {
enable(f);
}
/**
* @deprecated Use {@link #disable(JsonParser.Feature)} instead
*/
public final void disableParserFeature(JsonParser.Feature f) {
disable(f);
}
/**
* @deprecated Use {@link #configure(JsonParser.Feature, boolean)} instead
*/
public final void setParserFeature(JsonParser.Feature f, boolean state) {
configure(f, state);
}
/**
* @deprecated Use {@link #isEnabled(JsonParser.Feature)} instead
*/
public final boolean isParserFeatureEnabled(JsonParser.Feature f) {
return (_parserFeatures & f.getMask()) != 0;
}
/*
//////////////////////////////////////////////////////
// Configuration, generator settings
//////////////////////////////////////////////////////
*/
/**
* Method for enabling or disabling specified generator feature
* (check {@link JsonGenerator.Feature} for list of features)
*
* @since 1.2
*/
public final JsonFactory configure(JsonGenerator.Feature f, boolean state) {
if (state) {
enable(f);
} else {
disable(f);
}
return this;
}
/**
* Method for enabling specified generator features
* (check {@link JsonGenerator.Feature} for list of features)
*
* @since 1.2
*/
public JsonFactory enable(JsonGenerator.Feature f) {
_generatorFeatures |= f.getMask();
return this;
}
/**
* Method for disabling specified generator feature
* (check {@link JsonGenerator.Feature} for list of features)
*
* @since 1.2
*/
public JsonFactory disable(JsonGenerator.Feature f) {
_generatorFeatures &= ~f.getMask();
return this;
}
/**
* Checked whether specified generator feature is enabled.
*
* @since 1.2
*/
public final boolean isEnabled(JsonGenerator.Feature f) {
return (_generatorFeatures & f.getMask()) != 0;
}
// // // Older deprecated (as of 1.2) methods
/**
* @deprecated Use {@link #enable(JsonGenerator.Feature)} instead
*/
public final void enableGeneratorFeature(JsonGenerator.Feature f) {
enable(f);
}
/**
* @deprecated Use {@link #disable(JsonGenerator.Feature)} instead
*/
public final void disableGeneratorFeature(JsonGenerator.Feature f) {
disable(f);
}
/**
* @deprecated Use {@link #configure(JsonGenerator.Feature, boolean)} instead
*/
public final void setGeneratorFeature(JsonGenerator.Feature f, boolean state) {
configure(f, state);
}
/**
* @deprecated Use {@link #isEnabled(JsonGenerator.Feature)} instead
*/
public final boolean isGeneratorFeatureEnabled(JsonGenerator.Feature f) {
return isEnabled(f);
}
/*
//////////////////////////////////////////////////////
// Configuration, other
//////////////////////////////////////////////////////
*/
public JsonFactory setCodec(ObjectCodec oc) {
_objectCodec = oc;
return this;
}
public ObjectCodec getCodec() { return _objectCodec; }
/*
//////////////////////////////////////////////////////
// Reader factories
//////////////////////////////////////////////////////
*/
/**
* 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.
*
* @param f File that contains JSON content to parse
*/
public JsonParser createJsonParser(File f)
throws IOException, JsonParseException
{
return _createJsonParser(new FileInputStream(f), _createContext(f, true));
}
/**
* 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.
*
* @param url URL pointing to resource that contains JSON content to parse
*/
public JsonParser createJsonParser(URL url)
throws IOException, JsonParseException
{
return _createJsonParser(_optimizedStreamFromURL(url), _createContext(url, true));
}
/**
* 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) {@link org.codehaus.jackson.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.
*
* @param in InputStream to use for reading JSON content to parse
*/
public JsonParser createJsonParser(InputStream in)
throws IOException, JsonParseException
{
return _createJsonParser(in, _createContext(in, false));
}
/**
* Method for constructing json parser instance to parse
* the contents accessed via specified Reader.
* The read 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) {@link org.codehaus.jackson.JsonParser.Feature#AUTO_CLOSE_SOURCE}
* is enabled.
*
*
* @param r Reader to use for reading JSON content to parse
*/
public JsonParser createJsonParser(Reader r)
throws IOException, JsonParseException
{
return _createJsonParser(r, _createContext(r, false));
}
public JsonParser createJsonParser(byte[] data)
throws IOException, JsonParseException
{
return _createJsonParser(data, 0, data.length, _createContext(data, true));
}
public JsonParser createJsonParser(byte[] data, int offset, int len)
throws IOException, JsonParseException
{
return _createJsonParser(data, offset, len, _createContext(data, true));
}
public JsonParser createJsonParser(String content)
throws IOException, JsonParseException
{
// true -> we own the Reader (and must close); not a big deal
Reader r = new StringReader(content);
return _createJsonParser(r, _createContext(r, true));
}
/*
//////////////////////////////////////////////////////
// Generator factories
//////////////////////////////////////////////////////
*/
/**
* 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
* {@link JsonGenerator#close} is called (unless auto-closing
* feature,
* {@link org.codehaus.jackson.JsonGenerator.Feature#AUTO_CLOSE_TARGET}
* is enabled).
* Using application needs to close it explicitly if this is the case.
*
* @param out OutputStream to use for writing json content
* @param enc Character encoding to use
*/
public JsonGenerator createJsonGenerator(OutputStream out, JsonEncoding enc)
throws IOException
{
// false -> we won't manage the stream unless explicitly directed to
IOContext ctxt = _createContext(out, false);
ctxt.setEncoding(enc);
return _createJsonGenerator(_createWriter(out, enc, ctxt), ctxt);
}
/**
* 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
* {@link JsonGenerator#close} is called (unless auto-closing
* feature,
* {@link org.codehaus.jackson.JsonGenerator.Feature#AUTO_CLOSE_TARGET} is enabled).
* Using application needs to close it explicitly.
*
* @param out Writer to use for writing json content
*/
public JsonGenerator createJsonGenerator(Writer out)
throws IOException
{
IOContext ctxt = _createContext(out, false);
return _createJsonGenerator(out, ctxt);
}
/**
* 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
* {@link JsonGenerator#close} is called.
*
* @param f File to write contents to
* @param enc Character encoding to use
*/
public JsonGenerator createJsonGenerator(File f, JsonEncoding enc)
throws IOException
{
OutputStream out = new FileOutputStream(f);
// true -> yes, we have to manage the stream since we created it
IOContext ctxt = _createContext(out, true);
ctxt.setEncoding(enc);
return _createJsonGenerator(_createWriter(out, enc, ctxt), ctxt);
}
/*
///////////////////////////////////////////////////////////
// Internal methods
///////////////////////////////////////////////////////////
*/
/**
* Overridable construction method that actually instantiates desired generator.
*/
protected IOContext _createContext(Object srcRef, boolean resourceManaged)
{
return new IOContext(_getBufferRecycler(), srcRef, resourceManaged);
}
/**
* Overridable construction method that actually instantiates desired parser.
*/
protected JsonParser _createJsonParser(InputStream in, IOContext ctxt)
throws IOException, JsonParseException
{
return new ByteSourceBootstrapper(ctxt, in).constructParser(_parserFeatures, _objectCodec, _rootByteSymbols, _rootCharSymbols);
}
protected JsonParser _createJsonParser(Reader r, IOContext ctxt)
throws IOException, JsonParseException
{
return new ReaderBasedParser(ctxt, _parserFeatures, r, _objectCodec,
_rootCharSymbols.makeChild(isEnabled(JsonParser.Feature.CANONICALIZE_FIELD_NAMES),
isEnabled(JsonParser.Feature.INTERN_FIELD_NAMES)));
}
protected JsonParser _createJsonParser(byte[] data, int offset, int len, IOContext ctxt)
throws IOException, JsonParseException
{
// true -> managed (doesn't really matter; we have no stream!)
return new ByteSourceBootstrapper(ctxt, data, offset, len).constructParser(_parserFeatures, _objectCodec, _rootByteSymbols, _rootCharSymbols);
}
/**
* Overridable construction method that actually instantiates desired generator
*/
protected JsonGenerator _createJsonGenerator(Writer out, IOContext ctxt)
throws IOException
{
return new WriterBasedGenerator(ctxt, _generatorFeatures, _objectCodec, out);
}
/**
* Method used by factory to create buffer recycler instances
* for parsers and generators.
*
* Note: only public to give access for ObjectMapper
*/
public BufferRecycler _getBufferRecycler()
{
SoftReference ref = _recyclerRef.get();
BufferRecycler br = (ref == null) ? null : ref.get();
if (br == null) {
br = new BufferRecycler();
if (ref == null) {
_recyclerRef.set(new SoftReference(br));
}
}
return br;
}
/**
* 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.
*/
protected InputStream _optimizedStreamFromURL(URL url)
throws IOException
{
if ("file".equals(url.getProtocol())) {
/* Can not do this if the path refers
* to a network drive on windows. This fixes the problem;
* might not be needed on all platforms (NFS?), but should not
* matter a lot: performance penalty of extra wrapping is more
* relevant when accessing local file system.
*/
String host = url.getHost();
if (host == null || host.length() == 0) {
return new FileInputStream(url.getPath());
}
}
return url.openStream();
}
protected Writer _createWriter(OutputStream out, JsonEncoding enc, IOContext ctxt) throws IOException
{
if (enc == JsonEncoding.UTF8) { // We have optimized writer for UTF-8
return new UTF8Writer(ctxt, out);
}
// not optimal, but should do unless we really care about UTF-16/32 encoding speed
return new OutputStreamWriter(out, enc.getJavaName());
}
}