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//
//  ========================================================================
//  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.util.ajax;

import java.io.Externalizable;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.eclipse.jetty.util.IO;
import org.eclipse.jetty.util.Loader;
import org.eclipse.jetty.util.QuotedStringTokenizer;
import org.eclipse.jetty.util.TypeUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;

/**
 * JSON Parser and Generator.
 * 

* This class provides some static methods to convert POJOs to and from JSON * notation. The mapping from JSON to java is: * *

 *   object ==> Map
 *   array  ==> Object[]
 *   number ==> Double or Long
 *   string ==> String
 *   null   ==> null
 *   bool   ==> Boolean
 * 
* The java to JSON mapping is: * *
 *   String --> string
 *   Number --> number
 *   Map    --> object
 *   List   --> array
 *   Array  --> array
 *   null   --> null
 *   Boolean--> boolean
 *   Object --> string (dubious!)
 * 
* * The interface {@link JSON.Convertible} may be implemented by classes that * wish to externalize and initialize specific fields to and from JSON objects. * Only directed acyclic graphs of objects are supported. *

* The interface {@link JSON.Generator} may be implemented by classes that know * how to render themselves as JSON and the {@link #toString(Object)} method * will use {@link JSON.Generator#addJSON(Appendable)} to generate the JSON. * The class {@link JSON.Literal} may be used to hold pre-generated JSON object. *

* The interface {@link JSON.Convertor} may be implemented to provide static * converters for objects that may be registered with * {@link #registerConvertor(Class, Convertor)}. * These converters are looked up by class, interface and super class by * {@link #getConvertor(Class)}. *

* If a JSON object has a "class" field, then a java class for that name is * loaded and the method {@link #convertTo(Class,Map)} is used to find a * {@link JSON.Convertor} for that class. *

* If a JSON object has a "x-class" field then a direct lookup for a * {@link JSON.Convertor} for that class name is done (without loading the class). */ public class JSON { static final Logger LOG = Log.getLogger(JSON.class); public final static JSON DEFAULT = new JSON(); private Map _convertors = new ConcurrentHashMap(); private int _stringBufferSize = 1024; public JSON() { } /** * @return the initial stringBuffer size to use when creating JSON strings * (default 1024) */ public int getStringBufferSize() { return _stringBufferSize; } /** * @param stringBufferSize * the initial stringBuffer size to use when creating JSON * strings (default 1024) */ public void setStringBufferSize(int stringBufferSize) { _stringBufferSize = stringBufferSize; } /** * Register a {@link Convertor} for a class or interface. * * @param forClass * The class or interface that the convertor applies to * @param convertor * the convertor */ public static void registerConvertor(Class forClass, Convertor convertor) { DEFAULT.addConvertor(forClass,convertor); } public static JSON getDefault() { return DEFAULT; } @Deprecated public static void setDefault(JSON json) { } public static String toString(Object object) { StringBuilder buffer = new StringBuilder(DEFAULT.getStringBufferSize()); DEFAULT.append(buffer,object); return buffer.toString(); } public static String toString(Map object) { StringBuilder buffer = new StringBuilder(DEFAULT.getStringBufferSize()); DEFAULT.appendMap(buffer,object); return buffer.toString(); } public static String toString(Object[] array) { StringBuilder buffer = new StringBuilder(DEFAULT.getStringBufferSize()); DEFAULT.appendArray(buffer,array); return buffer.toString(); } /** * @param s * String containing JSON object or array. * @return A Map, Object array or primitive array parsed from the JSON. */ public static Object parse(String s) { return DEFAULT.parse(new StringSource(s),false); } /** * @param s * String containing JSON object or array. * @param stripOuterComment * If true, an outer comment around the JSON is ignored. * @return A Map, Object array or primitive array parsed from the JSON. */ public static Object parse(String s, boolean stripOuterComment) { return DEFAULT.parse(new StringSource(s),stripOuterComment); } /** * @param in * Reader containing JSON object or array. * @return A Map, Object array or primitive array parsed from the JSON. */ public static Object parse(Reader in) throws IOException { return DEFAULT.parse(new ReaderSource(in),false); } /** * @param in * Reader containing JSON object or array. * @param stripOuterComment * If true, an outer comment around the JSON is ignored. * @return A Map, Object array or primitive array parsed from the JSON. */ public static Object parse(Reader in, boolean stripOuterComment) throws IOException { return DEFAULT.parse(new ReaderSource(in),stripOuterComment); } /** * @deprecated use {@link #parse(Reader)} * @param in * Reader containing JSON object or array. * @return A Map, Object array or primitive array parsed from the JSON. */ @Deprecated public static Object parse(InputStream in) throws IOException { return DEFAULT.parse(new StringSource(IO.toString(in)),false); } /** * @deprecated use {@link #parse(Reader, boolean)} * @param in * Stream containing JSON object or array. * @param stripOuterComment * If true, an outer comment around the JSON is ignored. * @return A Map, Object array or primitive array parsed from the JSON. */ @Deprecated public static Object parse(InputStream in, boolean stripOuterComment) throws IOException { return DEFAULT.parse(new StringSource(IO.toString(in)),stripOuterComment); } /** * Convert Object to JSON * * @param object * The object to convert * @return The JSON String */ public String toJSON(Object object) { StringBuilder buffer = new StringBuilder(getStringBufferSize()); append(buffer,object); return buffer.toString(); } /** * Convert JSON to Object * * @param json * The json to convert * @return The object */ public Object fromJSON(String json) { Source source = new StringSource(json); return parse(source); } @Deprecated public void append(StringBuffer buffer, Object object) { append((Appendable)buffer,object); } /** * Append object as JSON to string buffer. * * @param buffer * the buffer to append to * @param object * the object to append */ public void append(Appendable buffer, Object object) { try { if (object == null) { buffer.append("null"); } // Most likely first else if (object instanceof Map) { appendMap(buffer,(Map)object); } else if (object instanceof String) { appendString(buffer,(String)object); } else if (object instanceof Number) { appendNumber(buffer,(Number)object); } else if (object instanceof Boolean) { appendBoolean(buffer,(Boolean)object); } else if (object.getClass().isArray()) { appendArray(buffer,object); } else if (object instanceof Character) { appendString(buffer,object.toString()); } else if (object instanceof Convertible) { appendJSON(buffer,(Convertible)object); } else if (object instanceof Generator) { appendJSON(buffer,(Generator)object); } else { // Check Convertor before Collection to support JSONCollectionConvertor Convertor convertor = getConvertor(object.getClass()); if (convertor != null) { appendJSON(buffer,convertor,object); } else if (object instanceof Collection) { appendArray(buffer,(Collection)object); } else { appendString(buffer,object.toString()); } } } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendNull(StringBuffer buffer) { appendNull((Appendable)buffer); } public void appendNull(Appendable buffer) { try { buffer.append("null"); } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendJSON(final StringBuffer buffer, final Convertor convertor, final Object object) { appendJSON((Appendable)buffer,convertor,object); } public void appendJSON(final Appendable buffer, final Convertor convertor, final Object object) { appendJSON(buffer,new Convertible() { public void fromJSON(Map object) { } public void toJSON(Output out) { convertor.toJSON(object,out); } }); } @Deprecated public void appendJSON(final StringBuffer buffer, Convertible converter) { appendJSON((Appendable)buffer,converter); } public void appendJSON(final Appendable buffer, Convertible converter) { ConvertableOutput out=new ConvertableOutput(buffer); converter.toJSON(out); out.complete(); } @Deprecated public void appendJSON(StringBuffer buffer, Generator generator) { generator.addJSON(buffer); } public void appendJSON(Appendable buffer, Generator generator) { generator.addJSON(buffer); } @Deprecated public void appendMap(StringBuffer buffer, Map map) { appendMap((Appendable)buffer,map); } public void appendMap(Appendable buffer, Map map) { try { if (map == null) { appendNull(buffer); return; } buffer.append('{'); Iterator iter = map.entrySet().iterator(); while (iter.hasNext()) { Map.Entry entry = (Map.Entry)iter.next(); QuotedStringTokenizer.quote(buffer,entry.getKey().toString()); buffer.append(':'); append(buffer,entry.getValue()); if (iter.hasNext()) buffer.append(','); } buffer.append('}'); } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendArray(StringBuffer buffer, Collection collection) { appendArray((Appendable)buffer,collection); } public void appendArray(Appendable buffer, Collection collection) { try { if (collection == null) { appendNull(buffer); return; } buffer.append('['); Iterator iter = collection.iterator(); boolean first = true; while (iter.hasNext()) { if (!first) buffer.append(','); first = false; append(buffer,iter.next()); } buffer.append(']'); } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendArray(StringBuffer buffer, Object array) { appendArray((Appendable)buffer,array); } public void appendArray(Appendable buffer, Object array) { try { if (array == null) { appendNull(buffer); return; } buffer.append('['); int length = Array.getLength(array); for (int i = 0; i < length; i++) { if (i != 0) buffer.append(','); append(buffer,Array.get(array,i)); } buffer.append(']'); } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendBoolean(StringBuffer buffer, Boolean b) { appendBoolean((Appendable)buffer,b); } public void appendBoolean(Appendable buffer, Boolean b) { try { if (b == null) { appendNull(buffer); return; } buffer.append(b?"true":"false"); } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendNumber(StringBuffer buffer, Number number) { appendNumber((Appendable)buffer,number); } public void appendNumber(Appendable buffer, Number number) { try { if (number == null) { appendNull(buffer); return; } buffer.append(String.valueOf(number)); } catch (IOException e) { throw new RuntimeException(e); } } @Deprecated public void appendString(StringBuffer buffer, String string) { appendString((Appendable)buffer,string); } public void appendString(Appendable buffer, String string) { if (string == null) { appendNull(buffer); return; } QuotedStringTokenizer.quote(buffer,string); } // Parsing utilities protected String toString(char[] buffer, int offset, int length) { return new String(buffer,offset,length); } protected Map newMap() { return new HashMap(); } protected Object[] newArray(int size) { return new Object[size]; } protected JSON contextForArray() { return this; } protected JSON contextFor(String field) { return this; } protected Object convertTo(Class type, Map map) { if (type != null && Convertible.class.isAssignableFrom(type)) { try { Convertible conv = (Convertible)type.newInstance(); conv.fromJSON(map); return conv; } catch (Exception e) { throw new RuntimeException(e); } } Convertor convertor = getConvertor(type); if (convertor != null) { return convertor.fromJSON(map); } return map; } /** * Register a {@link Convertor} for a class or interface. * * @param forClass * The class or interface that the convertor applies to * @param convertor * the convertor */ public void addConvertor(Class forClass, Convertor convertor) { _convertors.put(forClass.getName(),convertor); } /** * Lookup a convertor for a class. *

* If no match is found for the class, then the interfaces for the class are * tried. If still no match is found, then the super class and it's * interfaces are tried recursively. * * @param forClass * The class * @return a {@link JSON.Convertor} or null if none were found. */ protected Convertor getConvertor(Class forClass) { Class cls = forClass; Convertor convertor = _convertors.get(cls.getName()); if (convertor == null && this != DEFAULT) convertor = DEFAULT.getConvertor(cls); while (convertor == null && cls != Object.class) { Class[] ifs = cls.getInterfaces(); int i = 0; while (convertor == null && ifs != null && i < ifs.length) convertor = _convertors.get(ifs[i++].getName()); if (convertor == null) { cls = cls.getSuperclass(); convertor = _convertors.get(cls.getName()); } } return convertor; } /** * Register a {@link JSON.Convertor} for a named class or interface. * * @param name * name of a class or an interface that the convertor applies to * @param convertor * the convertor */ public void addConvertorFor(String name, Convertor convertor) { _convertors.put(name,convertor); } /** * Lookup a convertor for a named class. * * @param name * name of the class * @return a {@link JSON.Convertor} or null if none were found. */ public Convertor getConvertorFor(String name) { Convertor convertor = _convertors.get(name); if (convertor == null && this != DEFAULT) convertor = DEFAULT.getConvertorFor(name); return convertor; } public Object parse(Source source, boolean stripOuterComment) { int comment_state = 0; // 0=no comment, 1="/", 2="/*", 3="/* *" -1="//" if (!stripOuterComment) return parse(source); int strip_state = 1; // 0=no strip, 1=wait for /*, 2= wait for */ Object o = null; while (source.hasNext()) { char c = source.peek(); // handle // or /* comment if (comment_state == 1) { switch (c) { case '/': comment_state = -1; break; case '*': comment_state = 2; if (strip_state == 1) { comment_state = 0; strip_state = 2; } } } // handle /* */ comment else if (comment_state > 1) { switch (c) { case '*': comment_state = 3; break; case '/': if (comment_state == 3) { comment_state = 0; if (strip_state == 2) return o; } else comment_state = 2; break; default: comment_state = 2; } } // handle // comment else if (comment_state < 0) { switch (c) { case '\r': case '\n': comment_state = 0; default: break; } } // handle unknown else { if (!Character.isWhitespace(c)) { if (c == '/') comment_state = 1; else if (c == '*') comment_state = 3; else if (o == null) { o = parse(source); continue; } } } source.next(); } return o; } public Object parse(Source source) { int comment_state = 0; // 0=no comment, 1="/", 2="/*", 3="/* *" -1="//" while (source.hasNext()) { char c = source.peek(); // handle // or /* comment if (comment_state == 1) { switch (c) { case '/': comment_state = -1; break; case '*': comment_state = 2; } } // handle /* */ comment else if (comment_state > 1) { switch (c) { case '*': comment_state = 3; break; case '/': if (comment_state == 3) comment_state = 0; else comment_state = 2; break; default: comment_state = 2; } } // handle // comment else if (comment_state < 0) { switch (c) { case '\r': case '\n': comment_state = 0; break; default: break; } } // handle unknown else { switch (c) { case '{': return parseObject(source); case '[': return parseArray(source); case '"': return parseString(source); case '-': return parseNumber(source); case 'n': complete("null",source); return null; case 't': complete("true",source); return Boolean.TRUE; case 'f': complete("false",source); return Boolean.FALSE; case 'u': complete("undefined",source); return null; case 'N': complete("NaN",source); return null; case '/': comment_state = 1; break; default: if (Character.isDigit(c)) return parseNumber(source); else if (Character.isWhitespace(c)) break; return handleUnknown(source,c); } } source.next(); } return null; } protected Object handleUnknown(Source source, char c) { throw new IllegalStateException("unknown char '" + c + "'(" + (int)c + ") in " + source); } protected Object parseObject(Source source) { if (source.next() != '{') throw new IllegalStateException(); Map map = newMap(); char next = seekTo("\"}",source); while (source.hasNext()) { if (next == '}') { source.next(); break; } String name = parseString(source); seekTo(':',source); source.next(); Object value = contextFor(name).parse(source); map.put(name,value); seekTo(",}",source); next = source.next(); if (next == '}') break; else next = seekTo("\"}",source); } String xclassname = (String)map.get("x-class"); if (xclassname != null) { Convertor c = getConvertorFor(xclassname); if (c != null) return c.fromJSON(map); LOG.warn("No Convertor for x-class '{}'", xclassname); } String classname = (String)map.get("class"); if (classname != null) { try { Class c = Loader.loadClass(JSON.class,classname); return convertTo(c,map); } catch (ClassNotFoundException e) { LOG.warn("No Class for '{}'", classname); } } return map; } protected Object parseArray(Source source) { if (source.next() != '[') throw new IllegalStateException(); int size = 0; ArrayList list = null; Object item = null; boolean coma = true; while (source.hasNext()) { char c = source.peek(); switch (c) { case ']': source.next(); switch (size) { case 0: return newArray(0); case 1: Object array = newArray(1); Array.set(array,0,item); return array; default: return list.toArray(newArray(list.size())); } case ',': if (coma) throw new IllegalStateException(); coma = true; source.next(); break; default: if (Character.isWhitespace(c)) source.next(); else { coma = false; if (size++ == 0) item = contextForArray().parse(source); else if (list == null) { list = new ArrayList(); list.add(item); item = contextForArray().parse(source); list.add(item); item = null; } else { item = contextForArray().parse(source); list.add(item); item = null; } } } } throw new IllegalStateException("unexpected end of array"); } protected String parseString(Source source) { if (source.next() != '"') throw new IllegalStateException(); boolean escape = false; StringBuilder b = null; final char[] scratch = source.scratchBuffer(); if (scratch != null) { int i = 0; while (source.hasNext()) { if (i >= scratch.length) { // we have filled the scratch buffer, so we must // use the StringBuffer for a large string b = new StringBuilder(scratch.length * 2); b.append(scratch,0,i); break; } char c = source.next(); if (escape) { escape = false; switch (c) { case '"': scratch[i++] = '"'; break; case '\\': scratch[i++] = '\\'; break; case '/': scratch[i++] = '/'; break; case 'b': scratch[i++] = '\b'; break; case 'f': scratch[i++] = '\f'; break; case 'n': scratch[i++] = '\n'; break; case 'r': scratch[i++] = '\r'; break; case 't': scratch[i++] = '\t'; break; case 'u': char uc = (char)((TypeUtil.convertHexDigit((byte)source.next()) << 12) + (TypeUtil.convertHexDigit((byte)source.next()) << 8) + (TypeUtil.convertHexDigit((byte)source.next()) << 4) + (TypeUtil.convertHexDigit((byte)source.next()))); scratch[i++] = uc; break; default: scratch[i++] = c; } } else if (c == '\\') { escape = true; } else if (c == '\"') { // Return string that fits within scratch buffer return toString(scratch,0,i); } else { scratch[i++] = c; } } // Missing end quote, but return string anyway ? if (b == null) return toString(scratch,0,i); } else b = new StringBuilder(getStringBufferSize()); // parse large string into string buffer final StringBuilder builder=b; while (source.hasNext()) { char c = source.next(); if (escape) { escape = false; switch (c) { case '"': builder.append('"'); break; case '\\': builder.append('\\'); break; case '/': builder.append('/'); break; case 'b': builder.append('\b'); break; case 'f': builder.append('\f'); break; case 'n': builder.append('\n'); break; case 'r': builder.append('\r'); break; case 't': builder.append('\t'); break; case 'u': char uc = (char)((TypeUtil.convertHexDigit((byte)source.next()) << 12) + (TypeUtil.convertHexDigit((byte)source.next()) << 8) + (TypeUtil.convertHexDigit((byte)source.next()) << 4) + (TypeUtil.convertHexDigit((byte)source.next()))); builder.append(uc); break; default: builder.append(c); } } else if (c == '\\') { escape = true; } else if (c == '\"') { break; } else { builder.append(c); } } return builder.toString(); } public Number parseNumber(Source source) { boolean minus = false; long number = 0; StringBuilder buffer = null; longLoop: while (source.hasNext()) { char c = source.peek(); switch (c) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': number = number * 10 + (c - '0'); source.next(); break; case '-': case '+': if (number != 0) throw new IllegalStateException("bad number"); minus = true; source.next(); break; case '.': case 'e': case 'E': buffer = new StringBuilder(16); if (minus) buffer.append('-'); buffer.append(number); buffer.append(c); source.next(); break longLoop; default: break longLoop; } } if (buffer == null) return minus ? -1 * number : number; doubleLoop: while (source.hasNext()) { char c = source.peek(); switch (c) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case '-': case '.': case '+': case 'e': case 'E': buffer.append(c); source.next(); break; default: break doubleLoop; } } return new Double(buffer.toString()); } protected void seekTo(char seek, Source source) { while (source.hasNext()) { char c = source.peek(); if (c == seek) return; if (!Character.isWhitespace(c)) throw new IllegalStateException("Unexpected '" + c + " while seeking '" + seek + "'"); source.next(); } throw new IllegalStateException("Expected '" + seek + "'"); } protected char seekTo(String seek, Source source) { while (source.hasNext()) { char c = source.peek(); if (seek.indexOf(c) >= 0) { return c; } if (!Character.isWhitespace(c)) throw new IllegalStateException("Unexpected '" + c + "' while seeking one of '" + seek + "'"); source.next(); } throw new IllegalStateException("Expected one of '" + seek + "'"); } protected static void complete(String seek, Source source) { int i = 0; while (source.hasNext() && i < seek.length()) { char c = source.next(); if (c != seek.charAt(i++)) throw new IllegalStateException("Unexpected '" + c + " while seeking \"" + seek + "\""); } if (i < seek.length()) throw new IllegalStateException("Expected \"" + seek + "\""); } private final class ConvertableOutput implements Output { private final Appendable _buffer; char c = '{'; private ConvertableOutput(Appendable buffer) { _buffer = buffer; } public void complete() { try { if (c == '{') _buffer.append("{}"); else if (c != 0) _buffer.append("}"); } catch (IOException e) { throw new RuntimeException(e); } } public void add(Object obj) { if (c == 0) throw new IllegalStateException(); append(_buffer,obj); c = 0; } public void addClass(Class type) { try { if (c == 0) throw new IllegalStateException(); _buffer.append(c); _buffer.append("\"class\":"); append(_buffer,type.getName()); c = ','; } catch (IOException e) { throw new RuntimeException(e); } } public void add(String name, Object value) { try { if (c == 0) throw new IllegalStateException(); _buffer.append(c); QuotedStringTokenizer.quote(_buffer,name); _buffer.append(':'); append(_buffer,value); c = ','; } catch (IOException e) { throw new RuntimeException(e); } } public void add(String name, double value) { try { if (c == 0) throw new IllegalStateException(); _buffer.append(c); QuotedStringTokenizer.quote(_buffer,name); _buffer.append(':'); appendNumber(_buffer, value); c = ','; } catch (IOException e) { throw new RuntimeException(e); } } public void add(String name, long value) { try { if (c == 0) throw new IllegalStateException(); _buffer.append(c); QuotedStringTokenizer.quote(_buffer,name); _buffer.append(':'); appendNumber(_buffer, value); c = ','; } catch (IOException e) { throw new RuntimeException(e); } } public void add(String name, boolean value) { try { if (c == 0) throw new IllegalStateException(); _buffer.append(c); QuotedStringTokenizer.quote(_buffer,name); _buffer.append(':'); appendBoolean(_buffer,value?Boolean.TRUE:Boolean.FALSE); c = ','; } catch (IOException e) { throw new RuntimeException(e); } } } public interface Source { boolean hasNext(); char next(); char peek(); char[] scratchBuffer(); } public static class StringSource implements Source { private final String string; private int index; private char[] scratch; public StringSource(String s) { string = s; } public boolean hasNext() { if (index < string.length()) return true; scratch = null; return false; } public char next() { return string.charAt(index++); } public char peek() { return string.charAt(index); } @Override public String toString() { return string.substring(0,index) + "|||" + string.substring(index); } public char[] scratchBuffer() { if (scratch == null) scratch = new char[string.length()]; return scratch; } } public static class ReaderSource implements Source { private Reader _reader; private int _next = -1; private char[] scratch; public ReaderSource(Reader r) { _reader = r; } public void setReader(Reader reader) { _reader = reader; _next = -1; } public boolean hasNext() { getNext(); if (_next < 0) { scratch = null; return false; } return true; } public char next() { getNext(); char c = (char)_next; _next = -1; return c; } public char peek() { getNext(); return (char)_next; } private void getNext() { if (_next < 0) { try { _next = _reader.read(); } catch (IOException e) { throw new RuntimeException(e); } } } public char[] scratchBuffer() { if (scratch == null) scratch = new char[1024]; return scratch; } } /** * JSON Output class for use by {@link Convertible}. */ public interface Output { public void addClass(Class c); public void add(Object obj); public void add(String name, Object value); public void add(String name, double value); public void add(String name, long value); public void add(String name, boolean value); } /* ------------------------------------------------------------ */ /** * JSON Convertible object. Object can implement this interface in a similar * way to the {@link Externalizable} interface is used to allow classes to * provide their own serialization mechanism. *

* A JSON.Convertible object may be written to a JSONObject or initialized * from a Map of field names to values. *

* If the JSON is to be convertible back to an Object, then the method * {@link Output#addClass(Class)} must be called from within toJSON() * */ public interface Convertible { public void toJSON(Output out); public void fromJSON(Map object); } /** * Static JSON Convertor. *

* may be implemented to provide static convertors for objects that may be * registered with * {@link JSON#registerConvertor(Class, org.eclipse.jetty.util.ajax.JSON.Convertor)} * . These convertors are looked up by class, interface and super class by * {@link JSON#getConvertor(Class)}. Convertors should be used when the * classes to be converted cannot implement {@link Convertible} or * {@link Generator}. */ public interface Convertor { public void toJSON(Object obj, Output out); public Object fromJSON(Map object); } /** * JSON Generator. A class that can add it's JSON representation directly to * a StringBuffer. This is useful for object instances that are frequently * converted and wish to avoid multiple Conversions */ public interface Generator { public void addJSON(Appendable buffer); } /** * A Literal JSON generator A utility instance of {@link JSON.Generator} * that holds a pre-generated string on JSON text. */ public static class Literal implements Generator { private String _json; /** * Construct a literal JSON instance for use by * {@link JSON#toString(Object)}. If {@link Log#isDebugEnabled()} is * true, the JSON will be parsed to check validity * * @param json * A literal JSON string. */ public Literal(String json) { if (LOG.isDebugEnabled()) // TODO: Make this a configurable option on JSON instead! parse(json); _json = json; } @Override public String toString() { return _json; } public void addJSON(Appendable buffer) { try { buffer.append(_json); } catch(IOException e) { throw new RuntimeException(e); } } } }





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