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/*
* Copyright (C) 2020 Takashi Nakamoto .
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* Instances of this class are immutable.
*/
public class JSONText {
private final String text;
private final Object source;
private JSONText(String text, Object source) {
this.text = text;
this.source = source;
if ( ! ((source instanceof File) ||
(source instanceof URL) ||
(source instanceof String))) {
throw new IllegalArgumentException("source must be File, URL or String");
}
}
/**
* @return Contents of this JSON text.
*/
public String get() {
return text;
}
/**
* Return the object which represents the source of this JSON text.
*
* @return An instance of {@link File}, {@link URL} or {@link String}.
*/
public Object source() {
return source;
}
/**
* Tokenize this JSON text.
*
* @param errMsgFmt settings of error message format of {@link JSONParserException}
* @return Sequence of JSON tokens.
* @throws IOException if an I/O error occurs
* @throws JSONParserException if there is a syntax error in JSON text
*/
public List tokens(JSONParserErrorMessageFormat errMsgFmt)
throws IOException, JSONParserException {
List tokens = new ArrayList<>();
JSONLexer lexer = new JSONLexer(this, errMsgFmt);
JSONToken token;
while ((token = lexer.next()) != null)
tokens.add(token);
return tokens;
}
/**
* Tokenize this JSON text.
*
* @return Sequence of JSON tokens.
* @throws IOException if an I/O error occurs
* @throws JSONParserException if there is a syntax error in JSON text
*/
public List tokens()
throws IOException, JSONParserException {
JSONParserErrorMessageFormat errMsgFmt =
JSONParserErrorMessageFormat.builder().build();
return tokens(errMsgFmt);
}
/**
* Parse this JSON text.
*
* @param errMsgFmt settings of error message format of {@link JSONParserException}
* @return the root JSON value, or null if there is no value.
* @throws JSONParserException if there is a syntax error in the JSON text
* @throws IOException if an I/O error occurs
* @see RFC 8259 - 2. JSON Grammer
*/
public JSONValue parse(JSONParserErrorMessageFormat errMsgFmt)
throws IOException, JSONParserException {
List tokens = tokens(errMsgFmt);
JSONParser parser = new JSONParser(tokens, errMsgFmt);
return parser.parse();
}
/**
* Parse this JSON text.
*
* @return the root JSON value, or null if there is no value.
* @throws JSONParserException if there is a syntax error in the JSON text
* @throws IOException if an I/O error occurs
* @see RFC 8259 - 2. JSON Grammer
*/
public JSONValue parse()
throws IOException, JSONParserException {
JSONParserErrorMessageFormat errMsgFmt =
JSONParserErrorMessageFormat.builder().build();
return parse(errMsgFmt);
}
/**
* Return a string which represents a short name of the source of this
* JSON text. This is useful to construct an error message of JSON
* parsers.
*
* @return name of this JSON text.
*/
public String name() {
if (source instanceof File) {
return ((File) source).getName();
} else if (source instanceof URL) {
URL url = (URL) source;
String[] paths = url.getPath().split("/");
if (paths.length == 0) {
return url.toString();
} else {
return paths[paths.length - 1];
}
} else if (source instanceof String) {
return "(inner-string)";
}
throw new UnsupportedOperationException("source must be File, URL or String");
}
/**
* Return a string which represents the full path of the source
* of this JSON text. This is useful to construct an error message
* of JSON parsers.
*
* @return full path of this JSON text.
*/
public String fullName() {
if (source instanceof File ||
source instanceof URL) {
return source.toString();
} else if (source instanceof String) {
return "(inner-string)";
}
throw new UnsupportedOperationException("source must be File, URL or String");
}
@Override
public String toString() {
return "[JSONText from " + name() + "]";
}
/**
* Reads JSON text from a file and returns an instance of {@link JSONText} for further
* processing. The file must be encoded using UTF-8.
*
* @param file JSON text file.
* @return An instance of JSON text.
* @throws IOException in case of an I/O error
* @see RFC 8259 - 8.1. Character Encoding
*/
public static JSONText fromFile(File file) throws IOException {
if (file == null) {
throw new NullPointerException("file cannot be null");
}
String text = FileUtils.readFileToString(file, StandardCharsets.UTF_8);
return new JSONText(text, file);
}
/**
* Reads JSON text from a URL and returns an instance of {@link JSONText} for further
* processing. The text must be encoded using UTF-8.
*
* @param url URL of a JSON text file.
* @return An instance of JSON text.
* @throws IOException if an I/O exception occurs
* @see RFC 8259 - 8.1. Character Encoding
*/
public static JSONText fromURL(URL url) throws IOException {
if (url == null) {
throw new NullPointerException("url cannot be null");
}
/*
* TODO: RFC 8259 allows to add BOM (U+FEFF) to the beginning of
* a networked-transmitted JSON text. To improve the interoperability
* remove the BOM if exists.
*/
String text = IOUtils.toString(url, StandardCharsets.UTF_8);
return new JSONText(text, url);
}
/**
* Convert the given String to an instance of {@link JSONText}.
*
* @param str A string which contains JSON text.
* @return An instance of JSON text.
* @see RFC 8259 - 8.1. Character Encoding
*/
public static JSONText fromString(String str) {
if (str == null) {
throw new NullPointerException("str cannot be null");
}
return new JSONText(str, str);
}
}