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/* 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.format.InputAccessor;
import org.codehaus.jackson.format.MatchStrength;
import org.codehaus.jackson.io.*;
import org.codehaus.jackson.impl.ByteSourceBootstrapper;
import org.codehaus.jackson.impl.ReaderBasedParser;
import org.codehaus.jackson.impl.Utf8Generator;
import org.codehaus.jackson.impl.WriterBasedGenerator;
import org.codehaus.jackson.sym.BytesToNameCanonicalizer;
import org.codehaus.jackson.sym.CharsToNameCanonicalizer;
import org.codehaus.jackson.util.BufferRecycler;
import org.codehaus.jackson.util.VersionUtil;

/**
 * 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 implements Versioned { /** * Name used to identify JSON format * (and returned by {@link #getFormatName()} */ public final static String FORMAT_NAME_JSON = "JSON"; /** * 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 java.lang.ref.SoftRerefence} * to a {@link BufferRecycler} used to provide a low-cost * buffer recycling between reader and writer instances. */ final protected 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; /** * Currently enabled parser features. */ protected int _parserFeatures = DEFAULT_PARSER_FEATURE_FLAGS; /** * Currently enabled generator features. */ protected int _generatorFeatures = DEFAULT_GENERATOR_FEATURE_FLAGS; /** * 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 */ protected CharacterEscapes _characterEscapes; /** * Optional helper object that may decorate input sources, to do * additional processing on input during parsing. * * @since 1.8 */ protected InputDecorator _inputDecorator; /** * Optional helper object that may decorate output object, to do * additional processing on output during content generation. * * @since 1.8 */ protected OutputDecorator _outputDecorator; /* /********************************************************** /* Construction /********************************************************** */ /** * 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; } /* /********************************************************** /* Format detection functionality (since 1.8) /********************************************************** */ /** * 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 */ public String getFormatName() { /* Somewhat nasty check: since we can't make this abstract * (due to backwards compatibility concerns), need to prevent * format name "leakage" */ if (getClass() == JsonFactory.class) { return FORMAT_NAME_JSON; } return null; } public MatchStrength hasFormat(InputAccessor acc) throws IOException { // since we can't keep this abstract, only implement for "vanilla" instance if (getClass() == JsonFactory.class) { return hasJSONFormat(acc); } return null; } protected MatchStrength hasJSONFormat(InputAccessor acc) throws IOException { return ByteSourceBootstrapper.hasJSONFormat(acc); } /* /********************************************************** /* Versioned /********************************************************** */ @Override public Version version() { // VERSION is included under impl, so can't pass this class: return VersionUtil.versionFor(Utf8Generator.class); } /* /********************************************************** /* 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 */ @SuppressWarnings("dep-ann") public final void enableParserFeature(JsonParser.Feature f) { enable(f); } /** * @deprecated Use {@link #disable(JsonParser.Feature)} instead */ @SuppressWarnings("dep-ann") public final void disableParserFeature(JsonParser.Feature f) { disable(f); } /** * @deprecated Use {@link #configure(JsonParser.Feature, boolean)} instead */ @SuppressWarnings("dep-ann") public final void setParserFeature(JsonParser.Feature f, boolean state) { configure(f, state); } /** * @deprecated Use {@link #isEnabled(JsonParser.Feature)} instead */ @SuppressWarnings("dep-ann") public final boolean isParserFeatureEnabled(JsonParser.Feature f) { return (_parserFeatures & f.getMask()) != 0; } /** * Method for getting currently configured input decorator (if any; * there is no default decorator). * * @since 1.8 */ public InputDecorator getInputDecorator() { return _inputDecorator; } /** * Method for overriding currently configured input decorator * * @since 1.8 */ public JsonFactory setInputDecorator(InputDecorator d) { _inputDecorator = d; return this; } /* /********************************************************** /* 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; } /** * Check 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 */ @Deprecated public final void enableGeneratorFeature(JsonGenerator.Feature f) { enable(f); } /** * @deprecated Use {@link #disable(JsonGenerator.Feature)} instead */ @Deprecated public final void disableGeneratorFeature(JsonGenerator.Feature f) { disable(f); } /** * @deprecated Use {@link #configure(JsonGenerator.Feature, boolean)} instead */ @Deprecated public final void setGeneratorFeature(JsonGenerator.Feature f, boolean state) { configure(f, state); } /** * @deprecated Use {@link #isEnabled(JsonGenerator.Feature)} instead */ @Deprecated public final boolean isGeneratorFeatureEnabled(JsonGenerator.Feature f) { return isEnabled(f); } /** * Method for accessing custom escapes factory uses for {@link JsonGenerator}s * it creates. * * @since 1.8 */ public CharacterEscapes getCharacterEscapes() { return _characterEscapes; } /** * Method for defining custom escapes factory uses for {@link JsonGenerator}s * it creates. * * @since 1.8 */ public JsonFactory setCharacterEscapes(CharacterEscapes esc) { _characterEscapes = esc; return this; } /** * Method for getting currently configured output decorator (if any; * there is no default decorator). * * @since 1.8 */ public OutputDecorator getOutputDecorator() { return _outputDecorator; } /** * Method for overriding currently configured output decorator * * @since 1.8 */ public JsonFactory setOutputDecorator(OutputDecorator d) { _outputDecorator = d; return this; } /* /********************************************************** /* Configuration, other /********************************************************** */ /** * Method for associating a {@link ObjectCodec} (typically * a {@link org.codehaus.jackson.map.ObjectMapper}) with * this factory (and more importantly, parsers and generators * it constructs). This is needed to use data-binding methods * of {@link JsonParser} and {@link JsonGenerator} instances. */ 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 { // true, since we create InputStream from File IOContext ctxt = _createContext(f, true); InputStream in = new FileInputStream(f); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { in = _inputDecorator.decorate(ctxt, in); } return _createJsonParser(in, ctxt); } /** * 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 { // true, since we create InputStream from URL IOContext ctxt = _createContext(url, true); InputStream in = _optimizedStreamFromURL(url); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { in = _inputDecorator.decorate(ctxt, in); } return _createJsonParser(in, ctxt); } /** * 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 { IOContext ctxt = _createContext(in, false); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { in = _inputDecorator.decorate(ctxt, in); } return _createJsonParser(in, ctxt); } /** * Method for constructing parser for parsing * 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 { // false -> we do NOT own Reader (did not create it) IOContext ctxt = _createContext(r, false); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { r = _inputDecorator.decorate(ctxt, r); } return _createJsonParser(r, ctxt); } /** * Method for constructing parser for parsing * the contents of given byte array. */ public JsonParser createJsonParser(byte[] data) throws IOException, JsonParseException { IOContext ctxt = _createContext(data, true); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { InputStream in = _inputDecorator.decorate(ctxt, data, 0, data.length); if (in != null) { return _createJsonParser(in, ctxt); } } return _createJsonParser(data, 0, data.length, ctxt); } /** * Method for constructing parser for parsing * the contents of given byte array. * * @param data Buffer that contains data to parse * @param offset Offset of the first data byte within buffer * @param len Length of contents to parse within buffer */ public JsonParser createJsonParser(byte[] data, int offset, int len) throws IOException, JsonParseException { IOContext ctxt = _createContext(data, true); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { InputStream in = _inputDecorator.decorate(ctxt, data, offset, len); if (in != null) { return _createJsonParser(in, ctxt); } } return _createJsonParser(data, offset, len, ctxt); } /** * Method for constructing parser for parsing * contens of given String. */ public JsonParser createJsonParser(String content) throws IOException, JsonParseException { Reader r = new StringReader(content); // true -> we own the Reader (and must close); not a big deal IOContext ctxt = _createContext(r, true); // [JACKSON-512]: allow wrapping with InputDecorator if (_inputDecorator != null) { r = _inputDecorator.decorate(ctxt, r); } return _createJsonParser(r, ctxt); } /* /********************************************************** /* 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. *

* Note: there are formats that use fixed encoding (like most binary data formats) * and that ignore passed in encoding. * * @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); if (enc == JsonEncoding.UTF8) { // [JACKSON-512]: allow wrapping with _outputDecorator if (_outputDecorator != null) { out = _outputDecorator.decorate(ctxt, out); } return _createUTF8JsonGenerator(out, ctxt); } Writer w = _createWriter(out, enc, ctxt); // [JACKSON-512]: allow wrapping with _outputDecorator if (_outputDecorator != null) { w = _outputDecorator.decorate(ctxt, w); } return _createJsonGenerator(w, 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); // [JACKSON-512]: allow wrapping with _outputDecorator if (_outputDecorator != null) { out = _outputDecorator.decorate(ctxt, out); } return _createJsonGenerator(out, ctxt); } /** * 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). * * @since 1.8 */ public JsonGenerator createJsonGenerator(OutputStream out) throws IOException { return createJsonGenerator(out, JsonEncoding.UTF8); } /** * 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); if (enc == JsonEncoding.UTF8) { // [JACKSON-512]: allow wrapping with _outputDecorator if (_outputDecorator != null) { out = _outputDecorator.decorate(ctxt, out); } return _createUTF8JsonGenerator(out, ctxt); } Writer w = _createWriter(out, enc, ctxt); // [JACKSON-512]: allow wrapping with _outputDecorator if (_outputDecorator != null) { w = _outputDecorator.decorate(ctxt, w); } return _createJsonGenerator(w, ctxt); } /* /********************************************************** /* Factory methods used by factory for creating parser instances, /* overridable by sub-classes /********************************************************** */ /** * Overridable factory method that actually instantiates desired parser * given {@link 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. */ protected JsonParser _createJsonParser(InputStream in, IOContext ctxt) throws IOException, JsonParseException { return new ByteSourceBootstrapper(ctxt, in).constructParser(_parserFeatures, _objectCodec, _rootByteSymbols, _rootCharSymbols); } /** * Overridable factory method that actually instantiates parser * using given {@link 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. */ 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))); } /** * Overridable factory method that actually instantiates parser * using given {@link 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. */ protected JsonParser _createJsonParser(byte[] data, int offset, int len, IOContext ctxt) throws IOException, JsonParseException { return new ByteSourceBootstrapper(ctxt, data, offset, len).constructParser(_parserFeatures, _objectCodec, _rootByteSymbols, _rootCharSymbols); } /* /********************************************************** /* Factory methods used by factory for creating generator instances, /* overridable by sub-classes /********************************************************** */ /** * Overridable factory method that actually instantiates generator for * given {@link 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. */ protected JsonGenerator _createJsonGenerator(Writer out, IOContext ctxt) throws IOException { WriterBasedGenerator gen = new WriterBasedGenerator(ctxt, _generatorFeatures, _objectCodec, out); if (_characterEscapes != null) { gen.setCharacterEscapes(_characterEscapes); } return gen; } /** * Overridable factory method that actually instantiates generator for * given {@link 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. */ protected JsonGenerator _createUTF8JsonGenerator(OutputStream out, IOContext ctxt) throws IOException { Utf8Generator gen = new Utf8Generator(ctxt, _generatorFeatures, _objectCodec, out); if (_characterEscapes != null) { gen.setCharacterEscapes(_characterEscapes); } return gen; } protected Writer _createWriter(OutputStream out, JsonEncoding enc, IOContext ctxt) throws IOException { // note: this should not get called any more (caller checks, dispatches) 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()); } /* /********************************************************** /* Internal factory methods, other /********************************************************** */ /** * Overridable factory method that actually instantiates desired * context object. */ protected IOContext _createContext(Object srcRef, boolean resourceManaged) { return new IOContext(_getBufferRecycler(), srcRef, resourceManaged); } /** * 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(); _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(); } }





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