RoundFilter.java

package com.hubspot.jinjava.lib.filter;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Objects;

import org.apache.commons.lang3.math.NumberUtils;

import com.hubspot.jinjava.doc.annotations.JinjavaDoc;
import com.hubspot.jinjava.doc.annotations.JinjavaParam;
import com.hubspot.jinjava.doc.annotations.JinjavaSnippet;
import com.hubspot.jinjava.interpret.JinjavaInterpreter;

@JinjavaDoc(
    value = "Round the number to a given precision.",
    params = {
        @JinjavaParam(value = "value", type = "number", desc = "The number to round"),
        @JinjavaParam(value = "precision", type = "number", defaultValue = "0", desc = "Specifies the precision of rounding"),
        @JinjavaParam(value = "method", type = "enum common|ceil|floor", defaultValue = "common", desc = "Method of rounding: 'common' rounds either up or down, 'ceil' always rounds up, and 'floor' always rounds down.")
    },
    snippets = {
        @JinjavaSnippet(code = "{{ 42.55|round }}", output = "43.0", desc = "Note that even if rounded to 0 precision, a float is returned."),
        @JinjavaSnippet(code = "{{ 42.55|round(1, 'floor') }}", output = "42.5"),
        @JinjavaSnippet(code = "{{ 42.55|round|int }}", output = "43", desc = "If you need a real integer, pipe it through int")
    })
public class RoundFilter implements Filter {

  @Override
  public String getName() {
    return "round";
  }

  @Override
  public Object filter(Object var, JinjavaInterpreter interpreter, String... args) {
    BigDecimal result = BigDecimal.ZERO;
    try {
      result = new BigDecimal(Objects.toString(var));
    } catch (NumberFormatException e) {
    }

    int precision = 0;
    if (args.length > 0) {
      precision = NumberUtils.toInt(args[0]);
    }

    String method = "common";
    if (args.length > 1) {
      method = args[1];
    }

    RoundingMode roundingMode;

    switch (method) {
    case "ceil":
      roundingMode = RoundingMode.CEILING;
      break;
    case "floor":
      roundingMode = RoundingMode.FLOOR;
      break;
    case "common":
    default:
      roundingMode = RoundingMode.HALF_UP;
    }

    return result.setScale(precision, roundingMode);
  }

}