Make SelectionChangeEvent general and move it to event packacge (#13334)

Change-Id: I232bf1d021dd95dfa3e9697cef4d8e9987da3373

1 files changed, 110 insertions, 0 deletions

diff --git a/server/src/com/vaadin/event/SelectionChangeEvent.java b/server/src/com/vaadin/event/SelectionChangeEvent.java
new file mode 100644
index 0000000000..adc7b13d49
--- /dev/null
+++ b/server/src/com/vaadin/event/SelectionChangeEvent.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2000-2014 Vaadin Ltd.
+ * 
+ * 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 com.vaadin.event;
+
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.EventObject;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+import com.google.gwt.thirdparty.guava.common.collect.Sets;
+
+/**
+ * An event that specifies what in a selection has changed, and where the
+ * selection took place.
+ * 
+ * @since
+ * @author Vaadin Ltd
+ */
+public class SelectionChangeEvent extends EventObject {
+
+    private LinkedHashSet<Object> oldSelection;
+    private LinkedHashSet<Object> newSelection;
+
+    public SelectionChangeEvent(Object source, Collection<Object> oldSelection,
+            Collection<Object> newSelection) {
+        super(source);
+        this.oldSelection = new LinkedHashSet<Object>(oldSelection);
+        this.newSelection = new LinkedHashSet<Object>(newSelection);
+    }
+
+    /**
+     * A {@link Collection} of all the itemIds that became selected.
+     * <p>
+     * <em>Note:</em> this excludes all itemIds that might have been previously
+     * selected.
+     * 
+     * @return a Collection of the itemIds that became selected
+     */
+    public Set<Object> getAdded() {
+        return Sets.difference(newSelection, oldSelection);
+    }
+
+    /**
+     * A {@link Collection} of all the itemIds that became deselected.
+     * <p>
+     * <em>Note:</em> this excludes all itemIds that might have been previously
+     * deselected.
+     * 
+     * @return a Collection of the itemIds that became deselected
+     */
+    public Set<Object> getRemoved() {
+        return Sets.difference(oldSelection, newSelection);
+    }
+
+    /**
+     * The listener interface for receiving {@link SelectionChangeEvent
+     * SelectionChangeEvents}.
+     * 
+     * @since
+     * @author Vaadin Ltd
+     */
+    public interface SelectionChangeListener extends Serializable {
+        /**
+         * Notifies the listener that the selection state has changed.
+         * 
+         * @param event
+         *            the selection change event
+         */
+        void selectionChange(SelectionChangeEvent event);
+    }
+
+    /**
+     * The interface for adding and removing listeners for
+     * {@link SelectionChangeEvent SelectionChangeEvents}.
+     * 
+     * @since
+     * @author Vaadin Ltd
+     */
+    public interface SelectionChangeNotifier extends Serializable {
+        /**
+         * Registers a new selection change listener
+         * 
+         * @param listener
+         *            the listener to register
+         */
+        void addSelectionChangeListener(SelectionChangeListener listener);
+
+        /**
+         * Removes a previously registered selection change listener
+         * 
+         * @param listener
+         *            the listener to remove
+         */
+        void removeSelectionChangeListener(SelectionChangeListener listener);
+    }
+}