Simple query builder to prevent mess in where statements. Base idea is: one operation for one line.

QueryBuilder.java

public class QueryBuilder {

  private final StringBuilder sb;

	public QueryBuilder() {

		sb = new StringBuilder();
	}

	public QueryBuilder like(String columnName, String value) {

		sb.append(columnName);
		sb.append(" LIKE ");
		sb.append('\'');
		sb.append(value);
		sb.append('\'');
		return this;
	}

	public QueryBuilder eq(String columnName, String value) {

		sb.append(columnName);
		sb.append(" = ");
		sb.append('\'');
		sb.append(value);
		sb.append('\'');
		return this;
	}

	public QueryBuilder or() {

		sb.append(" OR ");
		return this;
	}

	public QueryBuilder and() {

		sb.append(" AND ");
		return this;
	}

	public QueryBuilder openBracket() {

		sb.append('(');
		return this;
	}

	public QueryBuilder closeBracket() {

		sb.append(')');
		return this;
	}

	public QueryBuilder append(String clause) {

		sb.append(clause);
		return this;
	}

	public String build() {

		return sb.toString();
	}
}