io.ebeaninternal.util.SortByClauseParser Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of ebean Show documentation

composite of common runtime dependencies for all platforms

There is a newer version: 15.8.1

package io.ebeaninternal.util;

import io.ebeaninternal.util.SortByClause.Property;

public final class SortByClauseParser {

  private final String rawSortBy;

  public static SortByClause parse(String rawSortByClause) {
    return new SortByClauseParser(rawSortByClause).parse();
  }

  private SortByClauseParser(String rawSortByClause) {
    this.rawSortBy = rawSortByClause.trim();
  }

  private SortByClause parse() {

    SortByClause sortBy = new SortByClause();

    String[] sections = rawSortBy.split(",");
    for (String section : sections) {
      Property p = parseSection(section.trim());
      if (p == null) {
        break;
      } else {
        sortBy.add(p);
      }

    }

    return sortBy;
  }

  private Property parseSection(String section) {
    if (section.isEmpty()) {
      return null;
    }
    String[] words = section.split(" ");
    if (words.length < 1 || words.length > 3) {
      throw new RuntimeException("Expecting 1 to 3 words in [" + section + "] but got [" + words.length + "]");
    }

    Boolean nullsHigh = null;
    boolean ascending = true;
    String propName = words[0];
    if (words.length > 1) {
      if (words[1].startsWith("nulls")) {
        nullsHigh = isNullsHigh(words[1]);

      } else {
        ascending = isAscending(words[1]);
      }
    }
    if (words.length > 2) {
      if (words[2].startsWith("nulls")) {
        nullsHigh = isNullsHigh(words[2]);

      } else {
        ascending = isAscending(words[2]);
      }
    }

    return new Property(propName, ascending, nullsHigh);
  }

  private Boolean isNullsHigh(String word) {
    if (SortByClause.NULLSHIGH.equalsIgnoreCase(word)) {
      return Boolean.TRUE;
    }
    if (SortByClause.NULLSLOW.equalsIgnoreCase(word)) {
      return Boolean.FALSE;
    }
    String m = "Expecting nullsHigh or nullsLow but got [" + word + "] in [" + rawSortBy + "]";
    throw new RuntimeException(m);
  }


  private boolean isAscending(String word) {
    if (SortByClause.ASC.equalsIgnoreCase(word)) {
      return true;
    }
    if (SortByClause.DESC.equalsIgnoreCase(word)) {
      return false;
    }
    String m = "Expect ASC or DESC but got [" + word + "] in [" + rawSortBy + "]";
    throw new RuntimeException(m);
  }

}