private Object readValue(JsonLexer lexer) throws ParseException {
if (isCurrentToken(lexer, NULL)) {
return readNull(lexer);
} else if (isCurrentToken(lexer, BOOLEAN)) {
return readBoolean(lexer);
} else if (isCurrentToken(lexer, NUMBER)) {
return readNumber(lexer);
} else if (isCurrentToken(lexer, STRING)) {
return readString(lexer);
} else if (isCurrentToken(lexer, OPEN_BRACKET)) {
return readArray(lexer);
} else if (isCurrentToken(lexer, OPEN_BRACE)) {
return readObject(lexer);
} else {
throw new ParseException(lexer.getLexeme(), VALUE_START_TOKENS);
}
}
private List<?> readArray(JsonLexer lexer) throws ParseException {
expectCurrentToken(lexer, OPEN_BRACKET);
expectMoveNext(lexer, NULL, BOOLEAN, NUMBER, STRING, OPEN_BRACKET, OPEN_BRACE, CLOSE_BRACKET);
List<Object> array = new ArrayList<Object>();
while (isCurrentToken(lexer, VALUE_START_TOKENS)) {
array.add(readValue(lexer));
if (isCurrentToken(lexer, CLOSE_BRACKET)) {
break;
} else {
expectCurrentToken(lexer, COMMA);
expectMoveNext(lexer, VALUE_START_TOKENS);
}
}
expectCurrentToken(lexer, CLOSE_BRACKET);
lexer.moveNext();
return array;
}
private Map<String, Object> readObject(JsonLexer lexer) throws ParseException {
expectCurrentToken(lexer, OPEN_BRACE);
expectMoveNext(lexer, STRING, CLOSE_BRACE);
Map<String, Object> object = new HashMap<String, Object>();
while (isCurrentToken(lexer, STRING)) {
String string = readString(lexer);
expectCurrentToken(lexer, COLON);
expectMoveNext(lexer, VALUE_START_TOKENS);
Object value = readValue(lexer);
object.put(string, value);
if (isCurrentToken(lexer, CLOSE_BRACE)) break;
else {
expectCurrentToken(lexer, COMMA);
expectMoveNext(lexer, VALUE_START_TOKENS);
}
}
expectCurrentToken(lexer, CLOSE_BRACE);
lexer.moveNext();
return object;
}
private String readString(JsonLexer lexer) throws ParseException {
expectCurrentToken(lexer, STRING);
String str = unescape((String) lexer.getValue());
lexer.moveNext();
return str.toString();
}
private Number readNumber(JsonLexer lexer) throws ParseException {
expectCurrentToken(lexer, NUMBER);
Number num = (Number) lexer.getValue();
lexer.moveNext();
return new BigDecimal(num.toString());
}
private Boolean readBoolean(JsonLexer lexer) throws ParseException {
expectCurrentToken(lexer, BOOLEAN);
Boolean bool = (Boolean) lexer.getValue();
lexer.moveNext();
return bool;
}
private Object readNull(JsonLexer lexer) throws ParseException {
expectCurrentToken(lexer, NULL);
lexer.moveNext();
return null;
}
private boolean isCurrentToken(JsonLexer lexer, Token... toks) {
for (Token tok : toks) {
if (lexer.getToken().equals(tok)) return true;
}
return false;
}
/**
* Attempts to move the lexer to the next token, and throws a ParseException with the expected
* next token types if not successful
*/
private void expectMoveNext(JsonLexer lexer, Token... expected) throws ParseException {
if (!lexer.moveNext()) {
throw new ParseException("no valid tokens from " + lexer.getOffset(), expected);
}
}
/**
* Checks that the current token is one of <tt>expected</tt>, and if not throws a ParseException
*/
private void expectCurrentToken(JsonLexer lexer, Token... expected) throws ParseException {
if (!isCurrentToken(lexer, expected)) {
throw new ParseException(lexer.getLexeme(), expected);
}
}
