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ASF GitHub Bot commented on THRIFT-2877: ---------------------------------------- Github user jsirois commented on the pull request: https://github.com/apache/thrift/pull/448#issuecomment-183458933 My 2 nonbinding cents: No reasonable client should care about hashCode values, only that the values meet the hashCode contract (this is true of any language). I don't think preserving them should ever be a goal. A second comment, not as helpful since it requires work, is that we should enshrine perf improvements using a tool like [jmh](http://openjdk.java.net/projects/code-tools/jmh/). We use this in [Apache Aurora](https://github.com/apache/aurora/tree/master/src/jmh/java/org/apache/aurora/benchmark) for example to ensure we have a shared history of performance improvements and regressions. > Optimize generated hashCode > --------------------------- > > Key: THRIFT-2877 > URL: https://issues.apache.org/jira/browse/THRIFT-2877 > Project: Thrift > Issue Type: Improvement > Components: Java - Compiler > Affects Versions: 0.9.3 > Reporter: Mike Rettig > Priority: Critical > > The generated java hashCode method allocates an ArrayList then appends the > fields to the list. Primitive fields will be boxed when added to the list. > The generated code shouldn't allocate a list or box primitives. The hashCode > can be calculated by using a primitive int and some static utility methods > which can return the hashCode for each type. > out << indent() << "@Override" << endl << indent() << "public int hashCode() > {" << endl; > 1839 indent_up(); > 1840 indent(out) << "List<Object> list = new ArrayList<Object>();" << endl; > 1841 > 1842 for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) { > 1843 out << endl; > 1844 > 1845 t_type* t = get_true_type((*m_iter)->get_type()); > 1846 bool is_optional = (*m_iter)->get_req() == t_field::T_OPTIONAL; > 1847 bool can_be_null = type_can_be_null(t); > 1848 string name = (*m_iter)->get_name(); > 1849 > 1850 string present = "true"; > 1851 > 1852 if (is_optional || can_be_null) { > 1853 present += " && (" + generate_isset_check(*m_iter) + ")"; > 1854 } > 1855 > 1856 indent(out) << "boolean present_" << name << " = " << present << ";" > << endl; > 1857 indent(out) << "list.add(present_" << name << ");" << endl; > 1858 indent(out) << "if (present_" << name << ")" << endl; > 1859 if (t->is_enum()) { > 1860 indent(out) << " list.add(" << name << ".getValue());" << endl; > 1861 } else { > 1862 indent(out) << " list.add(" << name << ");" << endl; > 1863 } > 1864 } > 1865 > 1866 out << endl; > 1867 indent(out) << "return list.hashCode();" << endl; > 1868 indent_down(); > 1869 indent(out) << "}" << endl << endl; > 1870 } -- This message was sent by Atlassian JIRA (v6.3.4#6332)