diff graal/com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/ReplaceTest.java @ 7267:a4b84ba6dc2e

Introduction of the Truffle API for efficient implementation of dynamic languages on top of the Graal VM. New projects com.oracle.truffle.api for the API definition and com.oracle.truffle.api.test for API tests and documentation.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Tue, 18 Dec 2012 15:33:55 +0100
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children 5e3d1a68664e
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+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api.test;
+
+import static org.junit.Assert.*;
+
+import java.util.*;
+
+import org.junit.*;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.nodes.*;
+
+
+/**
+ * <h3>Replacing Nodes at Run Time</h3>
+ *
+ * <p>
+ * The structure of the Truffle tree can be changed at run time by replacing nodes using the {@link Node#replace(Node)}
+ * method. This method will automatically change the child pointer in the parent of the node and replace it with a
+ * pointer to the new node.
+ * </p>
+ *
+ * <p>
+ * Replacing nodes is a costly operation, so it should not happen too often. The convention is that the implementation
+ * of the Truffle nodes should ensure that there are maximal a small (and constant) number of node replacements per
+ * Truffle node.
+ * </p>
+ *
+ * <p>
+ * The next part of the Truffle API introduction is at {@link com.oracle.truffle.api.test.CallTest}.
+ * </p>
+ */
+public class ReplaceTest {
+
+    @Test
+    public void test() {
+        TruffleRuntime runtime = Truffle.getRuntime();
+        UnresolvedNode leftChild = new UnresolvedNode("20");
+        UnresolvedNode rightChild = new UnresolvedNode("22");
+        TestRootNode rootNode = new TestRootNode(new ValueNode[]{leftChild, rightChild});
+        assertEquals(rootNode, leftChild.getParent());
+        assertEquals(rootNode, rightChild.getParent());
+        Iterator<Node> iterator = rootNode.getChildren().iterator();
+        Assert.assertEquals(leftChild, iterator.next());
+        Assert.assertEquals(rightChild, iterator.next());
+        Assert.assertFalse(iterator.hasNext());
+        CallTarget target = runtime.createCallTarget(rootNode);
+        Object result = target.call();
+        assertEquals(42, result);
+        assertEquals(42, target.call());
+        iterator = rootNode.getChildren().iterator();
+        Assert.assertEquals(ResolvedNode.class, iterator.next().getClass());
+        Assert.assertEquals(ResolvedNode.class, iterator.next().getClass());
+        Assert.assertFalse(iterator.hasNext());
+        iterator = rootNode.getChildren().iterator();
+        Assert.assertEquals(rootNode, iterator.next().getParent());
+        Assert.assertEquals(rootNode, iterator.next().getParent());
+        Assert.assertFalse(iterator.hasNext());
+    }
+
+    class TestRootNode extends RootNode {
+
+        @Children private ValueNode[] children;
+
+        public TestRootNode(ValueNode[] children) {
+            this.children = adoptChildren(children);
+        }
+
+        @Override
+        public Object execute(VirtualFrame frame) {
+            int sum = 0;
+            for (int i = 0; i < children.length; ++i) {
+                sum += children[i].execute();
+            }
+            return sum;
+        }
+    }
+
+    abstract class ValueNode extends Node {
+        abstract int execute();
+    }
+
+    class UnresolvedNode extends ValueNode {
+        private final String value;
+
+        public UnresolvedNode(String value) {
+            this.value = value;
+        }
+
+        @Override
+        int execute() {
+            int intValue = Integer.parseInt(value);
+            ResolvedNode newNode = this.replace(new ResolvedNode(intValue));
+            return newNode.execute();
+        }
+    }
+
+    class ResolvedNode extends ValueNode {
+        private final int value;
+
+        ResolvedNode(int value) {
+            this.value = value;
+        }
+
+        @Override
+        int execute() {
+            return value;
+        }
+    }
+}
+