ucsfilefilter.java

UCS (Ultra Corba Simulator) is one more powerful corba client/servant simulator tool than other simi

package com.corba.mnq.ui.jfc;

import javax.swing.filechooser.FileFilter;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * A convenience implementation of FileFilter that filters out all
 * files except for those type extensions that it knows about.
 * Extensions are of the type ".foo", which is typically found on
 * Windows and Unix boxes, but not on Macinthosh. Case is ignored.
 * Example - create a new filter that filerts out all files but gif
 * and jpg image files: JFileChooser chooser = new JFileChooser();
 * ExampleFileFilter filter = new ExampleFileFilter( new String{"gif",
 * "jpg"}, "JPEG & GIF Images")
 * chooser.addChoosableFileFilter(filter);
 * chooser.showOpenDialog(this);
 * 
 * @version 1.14 01/23/03
 * @author Jeff Dinkins
 */
public class UcsFileFilter extends FileFilter {

    private static String TYPE_UNKNOWN = "Type Unknown";

    private static String HIDDEN_FILE = "Hidden File";

    private Hashtable filters = null;

    private String description = null;

    private String fullDescription = null;

    private boolean useExtensionsInDescription = true;

    /**
     * Creates a file filter. If no filters are added, then all files
     * are accepted.
     * 
     * @see #addExtension
     */
    public UcsFileFilter() {
        this.filters = new Hashtable();
    }

    /**
     * Creates a file filter that accepts files with the given
     * extension. Example: new ExampleFileFilter("jpg");
     * 
     * @see #addExtension
     */
    public UcsFileFilter(String extension) {
        this(extension, null);
    }

    /**
     * Creates a file filter that accepts the given file type.
     * Example: new ExampleFileFilter("jpg", "JPEG Image Images");
     * Note that the "." before the extension is not needed. If
     * provided, it will be ignored.
     * 
     * @see #addExtension
     */
    public UcsFileFilter(String extension, String description) {
        this();
        if (extension != null)
            addExtension(extension);
        if (description != null)
            setDescription(description);
    }

    /**
     * Creates a file filter from the given string array. Example: new
     * ExampleFileFilter(String {"gif", "jpg"}); Note that the "."
     * before the extension is not needed adn will be ignored.
     * 
     * @see #addExtension
     */
    public UcsFileFilter(String[] filters) {
        this(filters, null);
    }

    /**
     * Creates a file filter from the given string array and
     * description. Example: new ExampleFileFilter(String {"gif",
     * "jpg"}, "Gif and JPG Images"); Note that the "." before the
     * extension is not needed and will be ignored.
     * 
     * @see #addExtension
     */
    public UcsFileFilter(String[] filters, String description) {
        this();
        for (int i = 0; i < filters.length; i++) {
            // add filters one by one
            addExtension(filters[i]);
        }
        if (description != null)
            setDescription(description);
    }

    /**
     * Return true if this file should be shown in the directory pane,
     * false if it shouldn't. Files that begin with "." are ignored.
     * 
     * @see #getExtension
     * @see FileFilter#accepts
     */
    public boolean accept(File f) {
        if (f != null) {
            if (f.isDirectory()) { return true; }
            String extension = getExtension(f);
            if (extension != null && filters.get(getExtension(f)) != null) { return true; }
            ;
        }
        return false;
    }

    /**
     * Return the extension portion of the file's name .
     * 
     * @see #getExtension
     * @see FileFilter#accept
     */
    public String getExtension(File f) {
        if (f != null) {
            String filename = f.getName();
            int i = filename.lastIndexOf('.');
            if (i > 0 && i < filename.length() - 1) { return filename.substring(i + 1)
                    .toLowerCase(); }
            ;
        }
        return null;
    }

    /**
     * Adds a filetype "dot" extension to filter against. For example:
     * the following code will create a filter that filters out all
     * files except those that end in ".jpg" and ".tif":
     * ExampleFileFilter filter = new ExampleFileFilter();
     * filter.addExtension("jpg"); filter.addExtension("tif"); Note
     * that the "." before the extension is not needed and will be
     * ignored.
     */
    public void addExtension(String extension) {
        if (filters == null) {
            filters = new Hashtable(5);
        }
        filters.put(extension.toLowerCase(), this);
        fullDescription = null;
    }

    /**
     * Returns the human readable description of this filter. For
     * example: "JPEG and GIF Image Files (*.jpg, *.gif)"
     * 
     * @see setDescription
     * @see setExtensionListInDescription
     * @see isExtensionListInDescription
     * @see FileFilter#getDescription
     */
    public String getDescription() {
        if (fullDescription == null) {
            if (description == null || isExtensionListInDescription()) {
                fullDescription = description == null ? "(" : description + " (";
                // build the description from the extension list
                Enumeration extensions = filters.keys();
                if (extensions != null) {
                    fullDescription += "." + (String) extensions.nextElement();
                    while (extensions.hasMoreElements()) {
                        fullDescription += ", ." + (String) extensions.nextElement();
                    }
                }
                fullDescription += ")";
            } else {
                fullDescription = description;
            }
        }
        return fullDescription;
    }

    /**
     * Sets the human readable description of this filter. For
     * example: filter.setDescription("Gif and JPG Images");
     * 
     * @see setDescription
     * @see setExtensionListInDescription
     * @see isExtensionListInDescription
     */
    public void setDescription(String description) {
        this.description = description;
        fullDescription = null;
    }

    /**
     * Determines whether the extension list (.jpg, .gif, etc) should
     * show up in the human readable description. Only relevent if a
     * description was provided in the constructor or using
     * setDescription();
     * 
     * @see getDescription
     * @see setDescription
     * @see isExtensionListInDescription
     */
    public void setExtensionListInDescription(boolean b) {
        useExtensionsInDescription = b;
        fullDescription = null;
    }

    /**
     * Returns whether the extension list (.jpg, .gif, etc) should
     * show up in the human readable description. Only relevent if a
     * description was provided in the constructor or using
     * setDescription();
     * 
     * @see getDescription
     * @see setDescription
     * @see setExtensionListInDescription
     */
    public boolean isExtensionListInDescription() {
        return useExtensionsInDescription;
    }
}