package io.crate.operation.operator;
import io.crate.metadata.FunctionInfo;
import io.crate.operation.Input;
import io.crate.planner.symbol.Function;
import io.crate.planner.symbol.Literal;
import io.crate.planner.symbol.Symbol;
import io.crate.types.DataTypes;
public class OrOperator extends Operator<Boolean> {
public static final String NAME = "op_or";
public static final FunctionInfo INFO = generateInfo(NAME, DataTypes.BOOLEAN);
public static void register(OperatorModule module) {
module.registerOperatorFunction(new OrOperator());
}
@Override
public FunctionInfo info() {
return INFO;
}
@Override
public Symbol normalizeSymbol(Function function) {
assert (function != null);
assert function.arguments().size() == 2;
Symbol left = function.arguments().get(0);
Symbol right = function.arguments().get(1);
if (left.symbolType().isValueSymbol() && right.symbolType().isValueSymbol()) {
return Literal.newLiteral(evaluate((Input) left, (Input) right));
}
/***
* true or x -> true
* false or x -> x
* null or x -> null or true -> return function as is
*/
if (left instanceof Input) {
Object value = ((Input) left).value();
if (value == null) {
return function;
}
assert value instanceof Boolean;
if ((Boolean) value) {
return Literal.newLiteral(true);
} else {
return right;
}
}
if (right instanceof Input) {
Object value = ((Input) right).value();
if (value == null) {
return function;
}
assert value instanceof Boolean;
if ((Boolean) value) {
return Literal.newLiteral(true);
} else {
return left;
}
}
return function;
}
@Override
public Boolean evaluate(Input<Boolean>... args) {
assert (args != null);
assert (args.length == 2);
assert (args[0] != null && args[1] != null);
// implement three valued logic.
// don't touch anything unless you have a good reason for it! :)
// http://en.wikipedia.org/wiki/Three-valued_logic
Boolean left = args[0].value();
Boolean right = args[1].value();
if (left == null && right == null) {
return null;
}
if (left == null) {
return (right) ? true : null;
}
if (right == null) {
return (left) ? true : null;
}
return left || right;
}
}