X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.databoard%2Fexamples%2Forg%2Fsimantics%2Fdataboard%2Fexample%2FAccessorExample.java;fp=bundles%2Forg.simantics.databoard%2Fexamples%2Forg%2Fsimantics%2Fdataboard%2Fexample%2FAccessorExample.java;h=a5d052272785aa73b0152dfe929826ae977976da;hb=969bd23cab98a79ca9101af33334000879fb60c5;hp=0000000000000000000000000000000000000000;hpb=866dba5cd5a3929bbeae85991796acb212338a08;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.databoard/examples/org/simantics/databoard/example/AccessorExample.java b/bundles/org.simantics.databoard/examples/org/simantics/databoard/example/AccessorExample.java
new file mode 100644
index 000000000..a5d052272
--- /dev/null
+++ b/bundles/org.simantics.databoard/examples/org/simantics/databoard/example/AccessorExample.java
@@ -0,0 +1,122 @@
+/*******************************************************************************
+ * Copyright (c) 2010- Association for Decentralized Information Management in
+ * Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *    VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+package org.simantics.databoard.example;
+
+import java.awt.geom.Rectangle2D;
+import java.util.Collection;
+import java.util.LinkedList;
+
+import org.simantics.databoard.Accessors;
+import org.simantics.databoard.Bindings;
+import org.simantics.databoard.accessor.Accessor;
+import org.simantics.databoard.accessor.Accessor.Listener;
+import org.simantics.databoard.accessor.RecordAccessor;
+import org.simantics.databoard.accessor.event.Event;
+import org.simantics.databoard.accessor.impl.ChangeSet;
+import org.simantics.databoard.accessor.interestset.InterestSet;
+
+public class AccessorExample {
+
+	public static void main(String[] args) throws Exception {
+		
+		//
+		// Accessor is a generic interface to access some kind of data.
+		// It doesn't say anything about the how data is stored in backend. 
+		//
+		// But!, there are many rules how the data is accessed.
+		//
+		// Some are in the interface and some are implemenation specific. 
+	    //
+		// The structure of the data must follow or be adaptable to the type system
+		// of databoard.
+		//
+		
+		
+		
+		// Lets create a java object, a record
+		Rectangle2D rect = new Rectangle2D.Double(10, 10, 200, 100);
+		
+		// And open an accessor to the object		
+		RecordAccessor ra = (RecordAccessor) Accessors.getAccessor(rect);
+		
+		// Note, the rule of java accessor type is that the instance must not be
+		// modified directly while an accessor is used.
+		
+		
+		
+		// We can see the fields of the rectangle as the tree structure of the 
+		// accessor is represented in the format of databoard's type system.   
+		System.out.println("Type: ");
+		System.out.println(ra.type());
+		
+		// Lets modify x-field of the rect instance
+		ra.getFieldAccessor("x").setValue( Bindings.DOUBLE, 100.0);
+		
+		// Lets print it out
+		System.out.println( rect );
+		
+		
+		
+		// Listen to changes, all changes.. 
+		InterestSet is = InterestSet.newInterestSet(ra.type(), true, true, true); 
+		Listener listener = new Accessor.Listener() {
+			public void onEvents(Collection<Event> events) {
+				for (Event e : events)
+					System.out.println("Event occured: "+e);
+			}
+		};
+		ra.addListener(listener, is, null, null);
+		// Change y-pos to 666
+		ra.getFieldAccessor("y").setValue( Bindings.DOUBLE, 666.0);		
+		ra.removeListener(listener);
+				
+		
+		
+		// Capture changes into a collection
+		ChangeSet changeSet = new ChangeSet();
+		ra.addListener(changeSet, is, null, null);
+		
+		// Lets modify width and height
+		ra.setFieldValue(2, Bindings.DOUBLE, 10.0);
+		ra.setFieldValue(3, Bindings.DOUBLE, 10.0);
+		
+		// And print out changes
+		System.out.println( rect );
+		ra.removeListener(changeSet);
+		
+		System.out.println();
+		System.out.println("Collected changes:");
+		for (Event e : changeSet.getEvents())
+			System.out.println(" o "+e);
+		System.out.println();
+
+		
+		
+		// We can apply the same modifications to another instance of rectangle
+		Rectangle2D rect2 = new Rectangle2D.Double(0, 0, 0, 0);
+		LinkedList<Event> rollback = new LinkedList<Event>();
+		
+		// Apply change set and gather rollback log
+		Accessors.getAccessor(rect2).apply(changeSet.getAndClearEvents(), rollback);		
+		System.out.println( rect2 );		
+		
+		// We can restore the rectangle by applying the rollback log 
+		Accessors.getAccessor(rect2).apply(rollback, null);
+		System.out.println( rect2 );		
+		
+		
+		// Java Accessor can be left for garbage collection
+		ra = null;
+	}
+	
+}
+