Application: gvSIG desktop

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package org.gvsig.fmap.dal.store.json.simplereaders;

import java.io.IOException;

import java.io.Reader;

import java.util.ArrayList;

import java.util.List;

import javax.json.JsonArray;

import javax.json.JsonObject;

import javax.json.JsonString;

import javax.json.JsonValue;

import org.apache.commons.io.IOUtils;

import org.apache.commons.lang3.StringUtils;

import org.gvsig.fmap.dal.store.json.JsonStoreParameters;

import static org.gvsig.fmap.dal.store.simplereader.SimpleReaderStoreParameters.HEADER;

import org.gvsig.fmap.dal.store.simplereader.simplereaders.AbstractSimpleReader;

import org.gvsig.json.Json;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

 *

 * @author jovivas

 */

public class JsonReader extends AbstractSimpleReader {

    private static final Logger LOGGER = LoggerFactory.getLogger(JsonReader.class);

    private JsonArray jsonData;

    private int columns;

    private String[] header;

    private int currentElement = 0;

    private final JsonStoreParameters parameters;

    public JsonReader(Reader reader, JsonStoreParameters theParameters) throws IOException {

        String input = IOUtils.toString(reader);

        this.jsonData = Json.createArray(input);

        this.columns = -1;

        this.header = null;

        this.parameters = theParameters;

        if (StringUtils.isBlank((CharSequence) this.parameters.getDynValue(HEADER))){

            this.parameters.setDynValue(HEADER, StringUtils.join(this.getHeader(), ','));

        }

    }

    @Override

    public String[] getHeader() throws IOException {

        if (this.header == null) {

            JsonObject firstItem = this.jsonData.getJsonObject(0);

            String[] theHeader = new String[firstItem.size()];

            int i = 0;

            for (String item : firstItem.keySet()) {

                theHeader[i++] = item;

            }

            this.header = theHeader;

        }

        return this.header;

    }

    @Override

    public int getColumnsCount() throws IOException {

        if (this.columns <= 0) {

            this.columns = this.getHeader().length;

        }

        return this.columns;

    }

    @Override

    public List<String> read() throws IOException {

        List<String> values = this.read(currentElement);

        if (values == null) {

            return null;

        }

        currentElement += 1;

        return values;

    }

    public List<String> read(int rowNumber) throws IOException {

        List<String> values = new ArrayList<>();

        if (rowNumber < jsonData.size()) {

            JsonObject feature = jsonData.getJsonObject(rowNumber);

            for (String columName : this.getHeader()) {

                if (feature.isNull(columName)) {

                    values.add("");

                } else {

                    JsonValue value = feature.get(columName);

                    switch (value.getValueType()) {

                        case FALSE:

                            values.add("false");

                            break;

                        case STRING:

                            values.add(((JsonString) value).getString());

                            break;

                        case TRUE:

                            values.add("true");

                            break;

                        case NULL:

                            values.add("");

                            break;

                        case NUMBER:

                        case ARRAY:

                        case OBJECT:

                        default:

                            values.add(value.toString());

                            break;

                    }

                }

            }

            return values;

        }

        return null;

    }

    @Override

    public void close() throws IOException {

        this.jsonData = null;

    }

    @Override

    public List<String> skip(int lines) throws IOException {

        this.currentElement += lines;

        if (this.currentElement > this.jsonData.size()) {

            return null;

        }

        return read(this.currentElement);

    }

    @Override

    public int getLine() {

        if (this.jsonData == null) {

            return 0;

        }

        return this.currentElement;

    }

    @Override

    public List<String> nextRowValues() {

        try {

            return this.read();

        } catch (IOException ex) {

            throw new RuntimeException(ex);

        }

    }

}