org.apache.poi.contrib.poibrowser.TreeReaderListener Maven / Gradle / Ivy
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package org.apache.poi.contrib.poibrowser;
import java.util.HashMap;
import java.util.Map;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.MutableTreeNode;
import org.apache.poi.hpsf.HPSFException;
import org.apache.poi.poifs.eventfilesystem.POIFSReaderEvent;
import org.apache.poi.poifs.eventfilesystem.POIFSReaderListener;
import org.apache.poi.poifs.filesystem.DocumentInputStream;
import org.apache.poi.poifs.filesystem.POIFSDocumentPath;
/**
* Organizes document information in a tree model in order to be
* e.g. displayed in a Swing {@link javax.swing.JTree}. An instance of this
* class is created with a root tree node ({@link MutableTreeNode}) and
* registered as a {@link POIFSReaderListener} with a {@link
* org.apache.poi.poifs.eventfilesystem.POIFSReader}. While the latter processes
* a POI filesystem it calls this class' {@link #processPOIFSReaderEvent} for
* each document it has been registered for. This method appends the document it
* processes at the appropriate position into the tree rooted at the
* above mentioned root tree node.
*
* The root tree node should be the root tree node of a {@link
* javax.swing.tree.TreeModel}.
*
* A top-level element in the tree model, i.e. an immediate child
* node of the root node, describes a POI filesystem as such. It is
* suggested to use the file's name (as seen by the operating system)
* but it could be any other string.
*
* The value of a tree node is a {@link DocumentDescriptor}. Unlike
* a {@link org.apache.poi.poifs.filesystem.POIFSDocument} which may be as heavy
* as many megabytes, an instance of {@link DocumentDescriptor} is a
* light-weight object and contains only some meta-information about a
* document.
*
* @author Rainer Klute <[email protected]>
*/
public class TreeReaderListener implements POIFSReaderListener
{
/**
* The tree's root node. POI filesystems get attached to this
* node as children.
*/
protected MutableTreeNode rootNode;
/**
* Maps filenames and POI document paths to their associated
* tree nodes.
*/
protected Map pathToNode;
/**
* The name of the file this {@link TreeReaderListener}
* processes. It is used to identify a top-level element in the
* tree. Alternatively any other string can be used. It is just a
* label which should identify a POI filesystem.
*/
protected String filename;
/**
* Creates a {@link TreeReaderListener} which should then be
* registered with a
* {@link org.apache.poi.poifs.eventfilesystem.POIFSReader}.
*
* @param filename The name of the POI filesystem, i.e. the name
* of the file the POI filesystem resides in. Alternatively any
* other string can be used.
*
* @param rootNode All document information will be attached as
* descendands to this tree node.
*/
public TreeReaderListener(final String filename,
final MutableTreeNode rootNode)
{
this.filename = filename;
this.rootNode = rootNode;
pathToNode = new HashMap(15); // Should be a reasonable guess.
}
/** The number of bytes to dump.
*/
private int nrOfBytes = 50;
public void setNrOfBytes(final int nrOfBytes)
{
this.nrOfBytes = nrOfBytes;
}
public int getNrOfBytes()
{
return nrOfBytes;
}
/**
* A document in the POI filesystem has been opened for
* reading. This method retrieves properties of the document and
* adds them to a tree model.
*/
public void processPOIFSReaderEvent(final POIFSReaderEvent event)
{
DocumentDescriptor d;
final DocumentInputStream is = event.getStream();
if (!is.markSupported())
throw new UnsupportedOperationException(is.getClass().getName() +
" does not support mark().");
/* Try do handle this document as a property set. We receive
* an exception if is no property set and handle it as a
* document of some other format. We are not concerned about
* that document's details. */
try
{
d = new PropertySetDescriptor(event.getName(), event.getPath(),
is, nrOfBytes);
}
catch (HPSFException ex)
{
d = new DocumentDescriptor(event.getName(), event.getPath(),
is, nrOfBytes);
}
catch (Throwable t)
{
System.err.println
("Unexpected exception while processing " +
event.getName() + " in " + event.getPath().toString());
t.printStackTrace(System.err);
throw new RuntimeException(t.getMessage());
}
is.close();
final MutableTreeNode parentNode = getNode(d.path, filename, rootNode);
final MutableTreeNode nameNode = new DefaultMutableTreeNode(d.name);
parentNode.insert(nameNode, 0);
final MutableTreeNode dNode = new DefaultMutableTreeNode(d);
nameNode.insert(dNode, 0);
}
/**
* Locates the parent node for a document entry in the tree
* model. If the parent node does not yet exist it will be
* created, too. This is done recursively, if needed.
*
* @param path The tree node for this path is located.
*
* @param fsName The name of the POI filesystem. This is just a
* string which is displayed in the tree at the top lovel.
*
* @param root The root node.
*/
private MutableTreeNode getNode(final POIFSDocumentPath path,
final String fsName,
final MutableTreeNode root)
{
MutableTreeNode n = (MutableTreeNode) pathToNode.get(path);
if (n != null)
/* Node found in map, just return it. */
return n;
if (path.length() == 0)
{
/* This is the root path of the POI filesystem. Its tree
* node is resp. must be located below the tree node of
* the POI filesystem itself. This is a tree node with the
* POI filesystem's name (this the operating system file's
* name) as its key it the path-to-node map. */
n = (MutableTreeNode) pathToNode.get(fsName);
if (n == null)
{
/* A tree node for the POI filesystem does not yet
* exist. */
n = new DefaultMutableTreeNode(fsName);
pathToNode.put(fsName, n);
root.insert(n, 0);
}
return n;
}
/* else - The path is somewhere down in the POI filesystem's
* hierarchy. We need the tree node of this path's parent
* and attach our new node to it. */
final String name = path.getComponent(path.length() - 1);
final POIFSDocumentPath parentPath = path.getParent();
final MutableTreeNode parentNode =
getNode(parentPath, fsName, root);
n = new DefaultMutableTreeNode(name);
pathToNode.put(path, n);
parentNode.insert(n, 0);
return n;
}
}