Now basing the implementation on a component graph.

[utils] / system / general / src / main / java / org / wamblee / system / graph / component / CheckRequiredProvidedMultiplicityVisitor.java

diff --git a/system/general/src/main/java/org/wamblee/system/graph/component/CheckRequiredProvidedMultiplicityVisitor.java b/system/general/src/main/java/org/wamblee/system/graph/component/CheckRequiredProvidedMultiplicityVisitor.java
new file mode 100644 (file)
index 0000000..526b892
--- /dev/null
+++ b/system/general/src/main/java/org/wamblee/system/graph/component/CheckRequiredProvidedMultiplicityVisitor.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2008 the original author or authors.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.system.graph.component;
+
+import java.util.List;
+
+import org.wamblee.system.core.SystemAssemblyException;
+import org.wamblee.system.graph.Edge;
+import org.wamblee.system.graph.Graph;
+import org.wamblee.system.graph.Node;
+import org.wamblee.system.graph.Visitor;
+
+/**
+ * Visitor that checks whether required and provided interfaces are matched
+ * appropriately:
+ * <ul>
+ * <li>Each required interface is connected to at most one provided interface
+ * </li>
+ * <li>Required interfaces that are not optional must be connected to precisely
+ * one provided interface</li>
+ * </ul>
+ * 
+ * @author Erik Brakkee
+ * 
+ */
+public class CheckRequiredProvidedMultiplicityVisitor implements Visitor {
+
+    private Graph _graph;
+
+    public CheckRequiredProvidedMultiplicityVisitor(Graph aGraph) {
+        _graph = aGraph;
+    }
+
+    @Override
+    public void visitEdge(Edge aEdge) {
+        // Empty
+    }
+
+    @Override
+    public void visitNode(Node aNode) {
+        if (aNode instanceof RequiredInterfaceNode) {
+            RequiredInterfaceNode required = (RequiredInterfaceNode) aNode;
+            List<Edge> edges = _graph.findOutgoing(aNode);
+            if (edges.size() > 1) {
+                createDuplicateException("Multiple internal providers of interface found", aNode, edges);
+            }
+            if (edges.size() == 0 && !required.getRequired().isOptional()) {
+                throw new SystemAssemblyException(
+                        aNode
+                                + ": mandatpory required interface not provided by other components started earlier");
+            }
+        } else if ( aNode instanceof ProvidedInterfaceNode) { 
+            List<Edge> edges = _graph.findOutgoing(aNode); 
+            if ( edges.size() > 1) { 
+                createDuplicateException("multiple internal matches for externally provided interface", aNode, edges);
+            }
+            if ( edges.size() == 0 ) { 
+                throw new SystemAssemblyException(aNode + ": external provided interface is not provided internally");
+            }
+        }
+    }
+
+    private void createDuplicateException(String aMsg, Node aNode, List<Edge> edges) {
+        StringBuffer buf = new StringBuffer();
+        buf.append(aNode
+                + ": " + aMsg + ": ");
+        for (Edge edge : edges) {
+            buf.append(edge.getTo() + "/ ");
+        }
+        throw new SystemAssemblyException(buf.toString());
+    }
+
+}