read line using java & maped filterd data [closed]

Answer 1

Here is the dirty solution. The assumption is that the "result" map contains only 1 month.

public class Reader
{
    public static void main(final String[] args) throws ParseException
    {
        BufferedReader reader = null;
        String animalName = "cat";
        // String animal = null;
        try
        {
            reader = new BufferedReader(new InputStreamReader(new FileInputStream("C:/1.txt")));
            Map<String, Integer> result = new LinkedHashMap<String, Integer>();
            Map<String, Integer> result2 = new LinkedHashMap<String, Integer>();

            while (reader.ready())
            {
                String line = reader.readLine();
                // split a line with spaces
                String[] values = line.split(",");
                String key = null;
                if (values[1].compareTo(animalName) == 0)
                {
                    key = values[0];
                    // animal=""+ ""+values[1].compareTo(animalName);
                    int sum = 0;
                    int count = 0;
                    // get a last counter and sum
                    if (result.containsKey(key))
                    {
                        sum = result.get(key);
                        count = result2.get(key);
                    }
                    else
                    {
                    }
                    // increment sum a count and save in the map with key
                    result.put(key, sum + Integer.parseInt(values[2]));
                    result2.put(key, count + 1);
                }
            }

            String date = result.keySet().iterator().next();
            DateFormat df = new SimpleDateFormat("mm/dd/yyyy");
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(df.parse(date));
            int monthStart = calendar.getActualMinimum(Calendar.DAY_OF_MONTH);
            int monthEnd = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
            calendar.set(Calendar.DAY_OF_MONTH, 0);

            // interate and print new output
            for (int i = monthStart; i < monthEnd; i++)
            {
                calendar.add(Calendar.DAY_OF_MONTH, 1);
                String key = df.format(calendar.getTime());
                if (result.containsKey(key))
                {
                    Integer sum = result.get(key);
                    Integer count = result2.get(key);
                    System.out.println(key + "   " + animalName + " " + sum + "\t" + count);
                }
                System.out.println(key);
            }
        }
        catch (FileNotFoundException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        catch (IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        finally
        {
            try
            {
                reader.close();
            }
            catch (IOException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }
}

Answer 2

You could use another map with the date as the key, and the results you got as value. Then you just loop through all the days in the month, and if the map contains the current date key, you print the corresponding value, else you only print the date.

Answer 3

Below is the code to do it. I am taking help of google-guava libraries as it helps me write less code ;-). If you just want in plain java then you can modify the code also if the logic needs some tweaking then look at processLine(...) method, that is where the change will go

Ok the only missing code I see is printing empty data for the dates that are not part of the input file in a sorted order. That is simple and leave it to you. Here is the hint: Increment date by 1 & loop until end of the month

I have run your sample file and it prints the below summary

11/3/2010   cat 89  3
11/3/2010   dog 3   1
11/2/2010   dog 4   1
11/2/2010   cat 20  3



import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;

import com.google.common.base.CharMatcher;
import com.google.common.base.Charsets;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.Maps;
import com.google.common.io.Files;
import com.google.common.io.LineProcessor;

public class AnimalSummaryBuilder
{
    private static final Splitter SPLITTER = Splitter.on(CharMatcher.anyOf(","));

    private static final Joiner JOINER = Joiner.on("\t");

    @SuppressWarnings("unchecked")
    public static void main(final String[] args) throws Exception
    {
        @SuppressWarnings("rawtypes")
        Map<Animal, Summary> result = Files.readLines(new File("c:/1.txt"), Charsets.ISO_8859_1, new LineProcessor() {

            private final Map<Animal, Summary> result = Maps.newHashMap();

            public Object getResult()
            {
                return result;
            }

            public boolean processLine(final String line) throws IOException
            {
                Iterator<String> columns = SPLITTER.split(line).iterator();

                String date = columns.next();
                String name = columns.next();
                int value = Integer.valueOf(columns.next()).intValue();

                Animal currentRow = new Animal(date, name);

                if (result.containsKey(currentRow))
                {
                    Summary summary = result.get(currentRow);
                    summary.increaseCount();
                    summary.addToTotal(value);
                }
                else
                {
                    Summary initialSummary = new Summary();
                    initialSummary.setCount(1);
                    initialSummary.setTotal(value);
                    result.put(currentRow, initialSummary);
                }
                return true;
            }
        });

        for (Map.Entry<Animal, Summary> entry : result.entrySet())
        {
            Animal animal = entry.getKey();
            Summary summary = entry.getValue();
            System.out.println(JOINER.join(animal.date, animal.name, summary.total, summary.count));
        }
    }

    final static class Animal
    {
        String date;

        String name;

        public Animal(final String date, final String n)
        {
            this.date = date;
            this.name = n;
        }

        @Override
        public int hashCode()
        {
            final int prime = 31;
            int result = 1;
            result = prime * result + ((date == null) ? 0 : date.hashCode());
            result = prime * result + ((name == null) ? 0 : name.hashCode());
            return result;
        }

        @Override
        public boolean equals(Object obj)
        {
            if (this == obj)
            {
                return true;
            }
            if (obj == null)
            {
                return false;
            }
            if (!(obj instanceof Animal))
            {
                return false;
            }
            Animal other = (Animal) obj;
            if (date == null)
            {
                if (other.date != null)
                {
                    return false;
                }
            }
            else if (!date.equals(other.date))
            {
                return false;
            }
            if (name == null)
            {
                if (other.name != null)
                {
                    return false;
                }
            }
            else if (!name.equals(other.name))
            {
                return false;
            }
            return true;
        }

    }

    final static class Summary
    {
        private int total;

        private int count;

        void setTotal(int value)
        {
            total = value;
        }

        void setCount(int i)
        {
            count = i;
        }

        void increaseCount()
        {
            count++;
        }

        void addToTotal(int valueToAdd)
        {
            total += valueToAdd;
        }
    }
}