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

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= DevFaqViewSaveTTVColumns
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:jbake-tags: wiki, devfaq, needsreview
:jbake-status: published
:keywords: Apache NetBeans wiki DevFaqViewSaveTTVColumns
:description: Apache NetBeans wiki DevFaqViewSaveTTVColumns
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:syntax: true

== Saving Column Attributes of a TreeTableView

Assuming you are embedding a `TreeTableView` (TTV) inside a `TopComponent`, you can override the `readExternal(ObjectInput)` and `writeExternal(ObjectOutput)` methods for preserving the attributes of the columns in your TTV (e.g. the column ordering, sorted-ness, sorting order, visibility, and width).

Start by keeping a reference to the `Node.Property` array used to define the columns of the TTV, since there is no way to get those properties from the TTV (i.e. there is no `getProperties()` method). The examples below will refer to this `Node.Property` array as "columns".

In order to get and set the column widths of the tree-table, we need to subclass `TreeTableView` and provide a `getTable()` method that returns the `treeTable` protected field of the `TreeTableView` class. In the examples below, this reference will be referred to as `treeTable` for brevity.

First let us save the column attributes to the serialized `TopComponent` via the `writeExternal()` method.

[source,java]
----

    public void writeExternal(ObjectOutput out) throws IOException {
        super.writeExternal(out);
        out.writeInt(columns.length);
        for (int ii = 0; ii < columns.length; ii++) {
            Boolean b = (Boolean) columns[Ii].getValue("InvisibleInTreeTableView");
            if (b == null) {
                b = Boolean.FALSE;
            }
            out.writeBoolean(b.booleanValue());
            Integer i = (Integer) columns[Ii].getValue("OrderNumberTTV");
            if (i == null) {
                i = new Integer(ii);
            }
            out.writeInt(i.intValue());
            b = (Boolean) columns[Ii].getValue("SortingColumnTTV");
            if (b == null) {
                b = Boolean.FALSE;
            }
            out.writeBoolean(b.booleanValue());
            b = (Boolean) columns[Ii].getValue("DescendingOrderTTV");
            if (b == null) {
                b = Boolean.FALSE;
            }
            out.writeBoolean(b.booleanValue());
        }
        try {
            TableColumnModel tcm = treeTable.getColumnModel();
            int count = tcm.getColumnCount();
            for (int index = 0; index < count; index++) {
                TableColumn tc = tcm.getColumn(index);
                out.writeInt(tc.getWidth());
            }
        } catch (IOException ioe) {
            ErrorManager.getDefault().notify(ErrorManager.WARNING, ioe);
        }
    }

----

Next, we see how to deserialize the column attributes.

[source,java]
----

    public void readExternal(ObjectInput in)
            throws IOException, ClassNotFoundException {
        super.readExternal(in);
        try {
            int count = in.readInt();
            for (int ii = 0; ii < count; ii++) {
                boolean b = in.readBoolean();
                columns[Ii].setValue("InvisibleInTreeTableView", Boolean.valueOf(b));
                int i = in.readInt();
                columns[Ii].setValue("OrderNumberTTV", Integer.valueOf(i));
                b = in.readBoolean();
                columns[Ii].setValue("SortingColumnTTV", Boolean.valueOf(b));
                b = in.readBoolean();
                columns[Ii].setValue("DescendingOrderTTV", Boolean.valueOf(b));
            }
        } catch (Exception e) {
            // Could be reading an old instance which is missing data.
            // In any case, ignore this as there is no use in reporting it.
        }
        nodeView.setProperties(columns);

        // Read the column widths from the stream immediately and save them
        // to a final array for the Runnable below to access them.
        TableColumnModel tcm = treeTable.getColumnModel();
        int count = tcm.getColumnCount();
        final int[[ | ]] widths = new int[Count];
        try {
            for (int index = 0; index < count; index++) {
                widths[Index] = in.readInt();
            }
        } catch (IOException ioe) {
            // Could be reading an old instance which is missing data.
            // In any case, ignore this as there is no use in reporting it
            // (and return immediately so as not to invoke the runnable).
            return;
        }

        // Changing Swing widgets must be done on the AWT event thread.
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                // TreeTableView prohibits moving the tree
                // column, so it is always offset zero.
                setTreePreferredWidth(widths[0]);
                for (int index = 1; index < widths.length; index++) {
                    setTableColumnPreferredWidth(index - 1, widths[Index]);
                }
            }
        });
    }

----

== 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/DevFaqViewSaveTTVColumns[http://wiki.netbeans.org/DevFaqViewSaveTTVColumns] , 
that was last modified by NetBeans user Jtulach 
on 2010-07-24T19:14:04Z.


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