netbeans.apache.org/src/content/wiki/DevFaqListenForSaveEvents.asciidoc

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= DevFaqListenForSaveEvents
:jbake-type: wiki
:jbake-tags: wiki, devfaq, needsreview
:jbake-status: published
:keywords: Apache NetBeans wiki DevFaqListenForSaveEvents
:description: Apache NetBeans wiki DevFaqListenForSaveEvents
:toc: left
:toc-title:
:syntax: true

=== How can I be notified when a file is modified and saved??

The link:http://bits.netbeans.org/dev/javadoc/org-openide-loaders/org/openide/loaders/DataObject.Registry.html[DataObject.Registry] in link:http://bits.netbeans.org/dev/javadoc/org-openide-loaders[LoadersAPI] gives you a set of modified DataObjects. You can also add a listener and be notified when the set of modified objects changes.

If you have a FileObject and want to listen for save events, you will need to get its DataObject by calling `link:http://bits.netbeans.org/dev/javadoc/org-openide-loaders/org/openide/loaders/DataObject.html#find(org.openide.filesystems.FileObject)[DataObject.find()]`.

To listen on a single DataObject for save events, simply add a `PropertyChangeListener` and listen for changes in `DataObject.PROP_MODIFIED`.

Note that listening for something to be saved is _not the same as listening for any changes in the file_ - you are really listening only for (directly or indirectly) user-initiated save events, as in the user pressing CTRL-S when the file is modified and opened in the editor.  For notifications about any changes in a file, instead attach a `link:DevFaqListenForChangesInNonExistentFile.asciidoc[FileChangeListener]` to the underlying `link:DevFaqFileObject.asciidoc[FileObject]`.

== Track the currently modified files by DataObject Registry listening - Sample code

[source,java]
----

DataObject.Registry registries = DataObject.getRegistry();
registries.addChangeListener(new ChangeListener() {
    public void stateChanged(ChangeEvent e) {
        System.out.println("ChangedListener: o = " + e.getSource().getClass());
        System.out.println("ChangedListener: o.source = " + e.getSource());
    }
});
DataObject[] objects = registries.getModified();
for (int i = 0; i < objects.length; i++) {
    DataObject dataObj = objects[I];
    System.out.println("data object name = " + dataObj.getName());
    System.out.println("data object pimary file name = " + dataObj.getPrimaryFile().getName());
    Set fss = dataObj.files();
    Iterator iter = fss.iterator();
    while (iter.hasNext()) {
        FileObject fo = (FileObject) iter.next();
        System.out.println("\tset file object: " + fo.getName());
    }
}

----

== Libraries needed

* Datasystems API
* File System API
* Nodes API
* Utilities API

=== Apache Migration Information

The content in this page was kindly donated by Oracle Corp. to the
Apache Software Foundation.

This page was exported from link:http://wiki.netbeans.org/DevFaqListenForSaveEvents[http://wiki.netbeans.org/DevFaqListenForSaveEvents] , 
that was last modified by NetBeans user Jtulach 
on 2010-07-24T19:50:39Z.


*NOTE:* This document was automatically converted to the AsciiDoc format on 2018-02-07, and needs to be reviewed.