SliceFilter.java

package com.hubspot.jinjava.lib.filter;

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

import com.google.common.collect.Iterators;
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.InterpretException;
import com.hubspot.jinjava.interpret.JinjavaInterpreter;
import com.hubspot.jinjava.util.ForLoop;
import com.hubspot.jinjava.util.ObjectIterator;

@JinjavaDoc(
    value = "Slice an iterator and return a list of lists containing those items.",
    params = {
        @JinjavaParam(value = "value", type = "sequence", desc = "The sequence or dict that the filter is applied to"),
        @JinjavaParam(value = "slices", type = "number", desc = "Specifies how many items will be sliced"),
        @JinjavaParam(value = "fill_with", desc = "Used to fill missing values on the last iteration")
    },
    snippets = {
        @JinjavaSnippet(
            desc = "create a div containing three ul tags that represent columns",
            code = "{% set items = ['laptops', 'tablets', 'smartphones', 'smart watches', 'TVs'] %}\n" +
                "<div class=\"columwrapper\">\n" +
                "  {% for column in items|slice(3) %}\n" +
                "    <ul class=\"column-{{ loop.index }}\">\n" +
                "    {% for item in column %}\n" +
                "      <li>{{ item }}</li>\n" +
                "    {% endfor %}\n" +
                "    </ul>\n" +
                "  {% endfor %}\n" +
                "</div>\n")
    })
public class SliceFilter implements Filter {

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

  @Override
  public Object filter(Object var, JinjavaInterpreter interpreter, String... args) {
    ForLoop loop = ObjectIterator.getLoop(var);

    if (args.length == 0) {
      throw new InterpretException(getName() + " requires number of slices argument", interpreter.getLineNumber());
    }

    int slices = NumberUtils.toInt(args[0], 3);
    return Iterators.paddedPartition(loop, slices);
  }

}