1 /*
2 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 import java.lang.reflect.code.Op;
25 import java.lang.reflect.code.type.ClassType;
26 import java.lang.reflect.code.type.MethodRef;
27 import java.lang.reflect.code.type.JavaType;
28 import java.util.stream.Stream;
29
30 import static java.lang.reflect.code.type.JavaType.parameterized;
31 import static java.lang.reflect.code.type.MethodRef.method;
32 import static java.lang.reflect.code.op.CoreOp.*;
33 import static java.lang.reflect.code.type.FunctionType.functionType;
34 import static java.lang.reflect.code.type.JavaType.type;
35
36 public interface Queryable<T> {
37 JavaType TYPE = type(Queryable.class);
38
39 QueryProvider provider();
40
41 // T
42 JavaType elementType();
43
44 // Queryable<T> -> Queryable<U>
45 FuncOp expression();
46
47 @SuppressWarnings("unchecked")
48 default Queryable<T> where(QuotablePredicate<T> f) {
49 LambdaOp l = (LambdaOp) f.quoted().op();
50 return (Queryable<T>) insertQuery(elementType(), "where", l);
51 }
52
53 @SuppressWarnings("unchecked")
54 default <R> Queryable<R> select(QuotableFunction<T, R> f) {
55 LambdaOp l = (LambdaOp) f.quoted().op();
56 return (Queryable<R>) insertQuery((JavaType) l.invokableType().returnType(), "select", l);
57 }
58
59 private Queryable<?> insertQuery(JavaType elementType, String methodName, LambdaOp lambdaOp) {
60 // Copy function expression, replacing return operation
61 FuncOp queryExpression = expression();
62 JavaType queryableType = parameterized(Queryable.TYPE, elementType);
63 FuncOp nextQueryExpression = func("query",
64 functionType(queryableType, queryExpression.invokableType().parameterTypes()))
65 .body(b -> b.inline(queryExpression, b.parameters(), (block, query) -> {
66 Op.Result fi = block.op(lambdaOp);
67
68 MethodRef md = method(Queryable.TYPE, methodName,
69 functionType(Queryable.TYPE, ((ClassType) lambdaOp.functionalInterface()).rawType()));
70 Op.Result queryable = block.op(invoke(queryableType, md, query, fi));
71
72 block.op(_return(queryable));
73 }));
74
75 return provider().createQuery(elementType, nextQueryExpression);
76 }
77
78 @SuppressWarnings("unchecked")
79 default QueryResult<Stream<T>> elements() {
80 JavaType resultType = parameterized(type(Stream.class), elementType());
81 return (QueryResult<Stream<T>>) insertQueryResult(resultType, "elements");
82 }
83
84 @SuppressWarnings("unchecked")
85 default QueryResult<Long> count() {
86 JavaType resultType = JavaType.LONG;
87 return (QueryResult<Long>) insertQueryResult(resultType, "count");
88 }
89
90 private QueryResult<?> insertQueryResult(JavaType resultType, String methodName) {
91 // Copy function expression, replacing return operation
92 FuncOp queryExpression = expression();
93 JavaType queryResultType = parameterized(QueryResult.TYPE, resultType);
94 FuncOp queryResultExpression = func("queryResult",
95 functionType(queryResultType, queryExpression.invokableType().parameterTypes()))
96 .body(b -> b.inline(queryExpression, b.parameters(), (block, query) -> {
97 MethodRef md = method(Queryable.TYPE, methodName,
98 functionType(QueryResult.TYPE));
99 Op.Result queryResult = block.op(invoke(queryResultType, md, query));
100
101 block.op(_return(queryResult));
102 }));
103
104 return provider().createQueryResult(resultType, queryResultExpression);
105 }
106 }