Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.g2d / src / org / simantics / g2d / diagram / handler / RelationshipHandler.java

diff --git a/bundles/org.simantics.g2d/src/org/simantics/g2d/diagram/handler/RelationshipHandler.java b/bundles/org.simantics.g2d/src/org/simantics/g2d/diagram/handler/RelationshipHandler.java
new file mode 100644 (file)
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+++ b/bundles/org.simantics.g2d/src/org/simantics/g2d/diagram/handler/RelationshipHandler.java
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+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.g2d.diagram.handler;\r
+\r
+import java.util.Collection;\r
+\r
+import org.simantics.g2d.diagram.IDiagram;\r
+import org.simantics.utils.ObjectUtils;\r
+\r
+/**\r
+ * A diagram handler for managing and querying arbitrary relationships between\r
+ * diagram objects. The management is done by claiming and denying relationships\r
+ * about the objects. A single relationship can only exist once or not at all\r
+ * between two objects, i.e. no duplicate relationships can be added.\r
+ * \r
+ * <p>\r
+ * There is no pre-defined meaning for a relationship - it is completely\r
+ * customizable by implementing your own {@link Relationship} interface.\r
+ * </p>\r
+ * \r
+ * @author Tuukka Lehtonen\r
+ */\r
+public interface RelationshipHandler extends DiagramHandler {\r
+\r
+    /**\r
+     * A simple holder class for a single relationship. Holds all the\r
+     * ingredients: two elements and the role of the relationship. The\r
+     * relationship is either uni- or bi-directional.\r
+     */\r
+    public final class Relation {\r
+        private final Object       subject;\r
+        private final Relationship relationship;\r
+        private final Object       object;\r
+\r
+        public Relation(Object subject, Relationship relationship, Object object) {\r
+            assert subject != null;\r
+            assert relationship != null;\r
+            assert object != null;\r
+            this.subject = subject;\r
+            this.relationship = relationship;\r
+            this.object = object;\r
+        }\r
+\r
+        public Object getSubject() {\r
+            return subject;\r
+        }\r
+\r
+        public Relationship getRelationship() {\r
+            return relationship;\r
+        }\r
+\r
+        public Object getObject() {\r
+            return object;\r
+        }\r
+\r
+        @Override\r
+        public int hashCode() {\r
+            return ((ObjectUtils.hashCode(subject) * 31)\r
+                    + ObjectUtils.hashCode(object) * 31)\r
+                    + ObjectUtils.hashCode(relationship);\r
+        }\r
+\r
+        @Override\r
+        public boolean equals(Object obj) {\r
+            if (obj == this)\r
+                return true;\r
+            if (!(obj instanceof Relation))\r
+                return false;\r
+            Relation other = (Relation) obj;\r
+            return subject.equals(other.subject) && object.equals(other.object) && relationship.equals(other.relationship);\r
+        }\r
+\r
+        @Override\r
+        public String toString() {\r
+            return "(" + subject + ", " + relationship + ", " + object + ")";\r
+        }\r
+    }\r
+\r
+    /**\r
+     * Claim a single relationship between the specified subject and object. An\r
+     * inverse relation will also be claimed if one exists.\r
+     * \r
+     * Subject and object should be alive (not destroyed). However it should not\r
+     * be enforced to be activated within the specified diagram, at the moment\r
+     * of invocation. This is because the relationship may be denied while the\r
+     * elements are still in the process of being added to or removed from a\r
+     * diagram.\r
+     * \r
+     * @param diagram the diagram to operate on\r
+     * @param subject the subject of the relationship\r
+     * @param predicate the relationship itself\r
+     * @param object the object of the relationship\r
+     */\r
+    void claim(IDiagram diagram, Object subject, Relationship predicate, Object object);\r
+\r
+    /**\r
+     * Deny a relationship. This will also deny the inverse relationship if one\r
+     * exists.\r
+     * \r
+     * Subject and object should be alive (not destroyed). However it should not\r
+     * be enforced to be activated within the specified diagram, at the moment\r
+     * of invocation. This is because the relationship may be denied while the\r
+     * elements are still in the process of being added to or removed from a\r
+     * diagram.\r
+     */\r
+    void deny(IDiagram diagram, Object subject, Relationship predicate, Object object);\r
+    void deny(IDiagram diagram, Relation relation);\r
+    void denyAll(IDiagram diagram, Object element);\r
+\r
+    /**\r
+     * Get all the relationships that are recorded for the specified element.\r
+     * \r
+     * @param diagram the diagram to operate on\r
+     * @param element the element to get all relations for\r
+     * @param result a collection for gathering the result of the query or null\r
+     *        to create a new collection for the result.\r
+     * @return\r
+     */\r
+    Collection<Relation> getRelations(IDiagram diagram, Object element, Collection<Relation> result);\r
+\r
+}\r