EventWriterJson.java

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package org.matsim.core.events.algorithms;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.util.MinimalPrettyPrinter;
import org.matsim.api.core.v01.events.Event;
import org.matsim.core.events.handler.BasicEventHandler;
import org.matsim.core.utils.io.IOUtils;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UncheckedIOException;
import java.util.Map;

public class EventWriterJson implements EventWriter, BasicEventHandler {
    private OutputStream out = null;
    private JsonGenerator jsonGenerator = null;

    public EventWriterJson(File outfile) {
        try {
            this.out = IOUtils.getOutputStream(outfile.toURI().toURL(), false);
            this.jsonGenerator = new JsonFactory().createGenerator(this.out);
            this.jsonGenerator.setPrettyPrinter(new MinimalPrettyPrinter("\n"));
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    public EventWriterJson(OutputStream stream) {
        try {
            this.out = stream;
            this.jsonGenerator = new JsonFactory().createGenerator(this.out);
            this.jsonGenerator.setPrettyPrinter(new MinimalPrettyPrinter("\n"));
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    @Override
    public void closeFile() {
        try {
            this.jsonGenerator.close();
            this.out.close();
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    @Override
    public void handleEvent(final Event event) {
        try {
            this.jsonGenerator.writeStartObject();
            Map<String, String> attr = event.getAttributes();
            for(Map.Entry<String, String> entry : attr.entrySet()) {
                this.jsonGenerator.writeStringField(entry.getKey(), entry.getValue());
            }
            this.jsonGenerator.writeEndObject();
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    @Override
    public void reset(final int iter) {
    }

}