private Expression translate0(RexNode expr) {
if (expr instanceof RexInputRef) {
// TODO: multiple inputs, e.g. joins
final Expression input = getInput(0);
final int index = ((RexInputRef) expr).getIndex();
final List<RelDataTypeField> fields = program.getInputRowType().getFieldList();
final RelDataTypeField field = fields.get(index);
if (fields.size() == 1) {
return input;
} else if (input.getType() == Object[].class) {
return Expressions.convert_(
Expressions.arrayIndex(input, Expressions.constant(field.getIndex())),
Types.box(JavaRules.EnumUtil.javaClass(typeFactory, field.getType())));
} else {
return Expressions.field(input, field.getName());
}
}
if (expr instanceof RexLocalRef) {
return translate(program.getExprList().get(((RexLocalRef) expr).getIndex()));
}
if (expr instanceof RexLiteral) {
return Expressions.constant(
((RexLiteral) expr).getValue(), typeFactory.getJavaClass(expr.getType()));
}
if (expr instanceof RexCall) {
final RexCall call = (RexCall) expr;
final SqlOperator operator = call.getOperator();
final ExpressionType expressionType = SQL_TO_LINQ_OPERATOR_MAP.get(operator);
if (expressionType != null) {
switch (operator.getSyntax()) {
case Binary:
return Expressions.makeBinary(
expressionType, translate(call.getOperands()[0]), translate(call.getOperands()[1]));
case Postfix:
case Prefix:
return Expressions.makeUnary(expressionType, translate(call.getOperands()[0]));
default:
throw new RuntimeException("unknown syntax " + operator.getSyntax());
}
}
Method method = SQL_OP_TO_JAVA_METHOD_MAP.get(operator);
if (method != null) {
List<Expression> exprs = translateList(Arrays.asList(call.operands));
return !Modifier.isStatic(method.getModifiers())
? Expressions.call(exprs.get(0), method, exprs.subList(1, exprs.size()))
: Expressions.call(method, exprs);
}
switch (expr.getKind()) {
default:
throw new RuntimeException("cannot translate expression " + expr);
}
}
throw new RuntimeException("cannot translate expression " + expr);
}
/** Returns the expression to access a table within a schema. */
public static Expression tableExpression(
Schema schema, Type elementType, String tableName, Class clazz) {
final MethodCallExpression expression;
if (Table.class.isAssignableFrom(clazz)) {
expression =
Expressions.call(
schema.getExpression(),
BuiltinMethod.SCHEMA_GET_TABLE.method,
Expressions.constant(tableName));
} else {
expression =
Expressions.call(
BuiltinMethod.SCHEMAS_QUERYABLE.method,
DataContext.ROOT,
schema.getExpression(),
Expressions.constant(elementType),
Expressions.constant(tableName));
}
return Types.castIfNecessary(clazz, expression);
}
/** Returns the expression for a sub-schema. */
public static Expression subSchemaExpression(Schema schema, String name, Class type) {
// (Type) schemaExpression.getSubSchema("name")
Expression call =
Expressions.call(
schema.getExpression(),
BuiltinMethod.SCHEMA_GET_SUB_SCHEMA.method,
Expressions.constant(name));
// CHECKSTYLE: IGNORE 2
//noinspection unchecked
if (false && type != null && !type.isAssignableFrom(Schema.class)) {
return unwrap(call, type);
}
return call;
}
public void testBlockBuilder2() {
BlockBuilder statements = new BlockBuilder();
Expression element = statements.append("element", Expressions.constant(null));
Expression comparator =
statements.append("comparator", Expressions.constant(null, Comparator.class));
Expression treeSet =
statements.append("treeSet", Expressions.new_(TreeSet.class, Arrays.asList(comparator)));
statements.add(Expressions.return_(null, Expressions.call(treeSet, "add", element)));
assertEquals(
"{\n"
+ " final java.util.Comparator comparator = null;\n"
+ " final java.util.TreeSet treeSet = new java.util.TreeSet(\n"
+ " comparator);\n"
+ " return treeSet.add(null);\n"
+ "}\n",
Expressions.toString(statements.toBlock()));
}
public void testCompile() throws NoSuchMethodException {
// Creating a parameter for the expression tree.
ParameterExpression param = Expressions.parameter(String.class);
// Creating an expression for the method call and specifying its
// parameter.
MethodCallExpression methodCall =
Expressions.call(Integer.class, "valueOf", Collections.<Expression>singletonList(param));
// The following statement first creates an expression tree,
// then compiles it, and then runs it.
int x =
Expressions.<Function1<String, Integer>>lambda(
methodCall, new ParameterExpression[] {param})
.getFunction()
.apply("1234");
assertEquals(1234, x);
}
public void testLambdaCallsTwoArgMethod() throws NoSuchMethodException {
// A parameter for the lambda expression.
ParameterExpression paramS = Expressions.parameter(String.class, "s");
ParameterExpression paramBegin = Expressions.parameter(Integer.TYPE, "begin");
ParameterExpression paramEnd = Expressions.parameter(Integer.TYPE, "end");
// This expression represents a lambda expression
// that adds 1 to the parameter value.
FunctionExpression lambdaExpr =
Expressions.lambda(
Expressions.call(
paramS,
String.class.getMethod("substring", Integer.TYPE, Integer.TYPE),
paramBegin,
paramEnd),
paramS,
paramBegin,
paramEnd);
// Compile and run the lambda expression.
String s = (String) lambdaExpr.compile().dynamicInvoke("hello world", 3, 7);
assertEquals("lo w", s);
}
/**
* Converts a schema expression to a given type by calling the {@link
* net.hydromatic.optiq.SchemaPlus#unwrap(Class)} method.
*/
public static Expression unwrap(Expression call, Class type) {
return Expressions.convert_(
Expressions.call(call, BuiltinMethod.SCHEMA_PLUS_UNWRAP.method, Expressions.constant(type)),
type);
}
public void testWrite() {
assertEquals(
"1 + 2.0F + 3L + Long.valueOf(4L)",
Expressions.toString(
Expressions.add(
Expressions.add(
Expressions.add(Expressions.constant(1), Expressions.constant(2F, Float.TYPE)),
Expressions.constant(3L, Long.TYPE)),
Expressions.constant(4L, Long.class))));
assertEquals(
"new java.math.BigDecimal(31415926L, 7)",
Expressions.toString(Expressions.constant(BigDecimal.valueOf(314159260, 8))));
// Parentheses needed, to override the left-associativity of +.
assertEquals(
"1 + (2 + 3)",
Expressions.toString(
Expressions.add(
Expressions.constant(1),
Expressions.add(Expressions.constant(2), Expressions.constant(3)))));
// No parentheses needed; higher precedence of * achieves the desired
// effect.
assertEquals(
"1 + 2 * 3",
Expressions.toString(
Expressions.add(
Expressions.constant(1),
Expressions.multiply(Expressions.constant(2), Expressions.constant(3)))));
assertEquals(
"1 * (2 + 3)",
Expressions.toString(
Expressions.multiply(
Expressions.constant(1),
Expressions.add(Expressions.constant(2), Expressions.constant(3)))));
// Parentheses needed, to overcome right-associativity of =.
assertEquals(
"(1 = 2) = 3",
Expressions.toString(
Expressions.assign(
Expressions.assign(Expressions.constant(1), Expressions.constant(2)),
Expressions.constant(3))));
// Ternary operator.
assertEquals(
"1 < 2 ? (3 < 4 ? 5 : 6) : 7 < 8 ? 9 : 10",
Expressions.toString(
Expressions.condition(
Expressions.lessThan(Expressions.constant(1), Expressions.constant(2)),
Expressions.condition(
Expressions.lessThan(Expressions.constant(3), Expressions.constant(4)),
Expressions.constant(5),
Expressions.constant(6)),
Expressions.condition(
Expressions.lessThan(Expressions.constant(7), Expressions.constant(8)),
Expressions.constant(9),
Expressions.constant(10)))));
assertEquals(
"0 + (double) (2 + 3)",
Expressions.toString(
Expressions.add(
Expressions.constant(0),
Expressions.convert_(
Expressions.add(Expressions.constant(2), Expressions.constant(3)),
Double.TYPE))));
assertEquals(
"a.empno",
Expressions.toString(
Expressions.field(Expressions.parameter(Linq4jTest.Employee.class, "a"), "empno")));
assertEquals(
"java.util.Collections.EMPTY_LIST",
Expressions.toString(Expressions.field(null, Collections.class, "EMPTY_LIST")));
final ParameterExpression paramX = Expressions.parameter(String.class, "x");
assertEquals(
"new net.hydromatic.linq4j.function.Function1() {\n"
+ " public int apply(String x) {\n"
+ " return x.length();\n"
+ " }\n"
+ " public Object apply(Object x) {\n"
+ " return apply(\n"
+ " (String) x);\n"
+ " }\n"
+ "}\n",
Expressions.toString(
Expressions.lambda(
Function1.class,
Expressions.call(paramX, "length", Collections.<Expression>emptyList()),
Arrays.asList(paramX))));
assertEquals(
"new String[] {\n" + " \"foo\",\n" + " null,\n" + " \"bar\\\"baz\"}",
Expressions.toString(
Expressions.newArrayInit(
String.class,
Arrays.<Expression>asList(
Expressions.constant("foo"),
Expressions.constant(null),
Expressions.constant("bar\"baz")))));
assertEquals(
"(int) ((String) (Object) \"foo\").length()",
Expressions.toString(
Expressions.convert_(
Expressions.call(
Expressions.convert_(
Expressions.convert_(Expressions.constant("foo"), Object.class),
String.class),
"length",
Collections.<Expression>emptyList()),
Integer.TYPE)));
// resolving a static method
assertEquals(
"Integer.valueOf(\"0123\")",
Expressions.toString(
Expressions.call(
Integer.class,
"valueOf",
Collections.<Expression>singletonList(Expressions.constant("0123")))));
// precedence of not and instanceof
assertEquals(
"!(o instanceof String)",
Expressions.toString(
Expressions.not(
Expressions.typeIs(Expressions.parameter(Object.class, "o"), String.class))));
// not not
assertEquals(
"!!(o instanceof String)",
Expressions.toString(
Expressions.not(
Expressions.not(
Expressions.typeIs(Expressions.parameter(Object.class, "o"), String.class)))));
}
public void testWriteAnonymousClass() {
// final List<String> baz = Arrays.asList("foo", "bar");
// new AbstractList<String>() {
// public int size() {
// return baz.size();
// }
// public String get(int index) {
// return ((String) baz.get(index)).toUpperCase();
// }
// }
final ParameterExpression bazParameter =
Expressions.parameter(Types.of(List.class, String.class), "baz");
final ParameterExpression indexParameter = Expressions.parameter(Integer.TYPE, "index");
BlockExpression e =
Expressions.block(
Expressions.declare(
Modifier.FINAL,
bazParameter,
Expressions.call(
Arrays.class,
"asList",
Arrays.<Expression>asList(
Expressions.constant("foo"), Expressions.constant("bar")))),
Expressions.statement(
Expressions.new_(
Types.of(AbstractList.class, String.class),
Collections.<Expression>emptyList(),
Arrays.<MemberDeclaration>asList(
Expressions.fieldDecl(
Modifier.PUBLIC | Modifier.FINAL,
Expressions.parameter(String.class, "qux"),
Expressions.constant("xyzzy")),
Expressions.methodDecl(
Modifier.PUBLIC,
Integer.TYPE,
"size",
Collections.<ParameterExpression>emptyList(),
Blocks.toFunctionBlock(
Expressions.call(
bazParameter, "size", Collections.<Expression>emptyList()))),
Expressions.methodDecl(
Modifier.PUBLIC,
String.class,
"get",
Arrays.asList(indexParameter),
Blocks.toFunctionBlock(
Expressions.call(
Expressions.convert_(
Expressions.call(
bazParameter,
"get",
Arrays.<Expression>asList(indexParameter)),
String.class),
"toUpperCase",
Collections.<Expression>emptyList())))))));
assertEquals(
"{\n"
+ " final java.util.List<String> baz = java.util.Arrays.asList(\"foo\", \"bar\");\n"
+ " new java.util.AbstractList<String>(){\n"
+ " public final String qux = \"xyzzy\";\n"
+ " public int size() {\n"
+ " return baz.size();\n"
+ " }\n"
+ "\n"
+ " public String get(int index) {\n"
+ " return ((String) baz.get(index)).toUpperCase();\n"
+ " }\n"
+ "\n"
+ " };\n"
+ "}\n",
Expressions.toString(e));
}