com.dslplatform.json.parsers.JsArrayParser Maven / Gradle / Ivy

Go to download
package com.dslplatform.json.parsers;

import com.dslplatform.json.JsonReader;
import com.dslplatform.json.ParsingException;
import jsonvalues.JsArray;
import jsonvalues.JsNull;
import jsonvalues.JsValue;
import jsonvalues.spec.Error;

import java.io.IOException;
import java.util.Optional;
import java.util.function.Function;

abstract class JsArrayParser {

    final static JsArray EMPTY = JsArray.empty();
    private final AbstractParser parser;

    public JsArrayParser(final AbstractParser parser) {
        this.parser = parser;
    }

    JsValue nullOrArray(final JsonReader reader) throws JsParserException {
        try {
            return reader.wasNull() ? JsNull.NULL : array(reader);
        } catch (ParsingException e) {
            throw new JsParserException(e.getMessage());
        }
    }

    public JsArray array(final JsonReader reader) throws JsParserException {
        try {
            if (ifIsEmptyArray(reader)) return EMPTY;
            JsArray buffer = EMPTY.append(parser.value(reader));
            while (reader.getNextToken() == ',') {
                reader.getNextToken();
                buffer = buffer.append(parser.value(reader));
            }
            reader.checkArrayEnd();
            return buffer;
        } catch (IOException e) {
            throw new JsParserException(e.getMessage());
        }
    }

    boolean ifIsEmptyArray(final JsonReader reader) throws JsParserException {
        try {
            if (reader.last() != '[')
                throw reader.newParseError("Expecting '[' for list start");
            reader.getNextToken();
            return reader.last() == ']';
        } catch (IOException e) {
            throw new JsParserException(e.getMessage());
        }
    }



    public JsValue nullOrArraySuchThat(final JsonReader reader,
                                       final Function> fn
                                      ) throws JsParserException {
        try {
            return reader.wasNull() ? JsNull.NULL : arraySuchThat(reader,
                                                                  fn
                                                                 );
        } catch (ParsingException e) {
            throw new JsParserException(e.getMessage());
        }
    }

    public JsArray arraySuchThat(final JsonReader reader,
                                 final Function> fn
                                ) throws JsParserException {
        try {
            final JsArray         array  = array(reader);
            final Optional result = fn.apply(array);
            if (!result.isPresent()) return array;
            throw reader.newParseError(result.toString());
        } catch (ParsingException e) {
            throw new JsParserException(e.getMessage());

        }

    }

}