jmguifilefilter.java

梦界家园程序开发基底框架

package jm.framework.gui.container;

import java.io.File;

import javax.swing.filechooser.FileFilter;
import java.util.Hashtable;
import java.util.Enumeration;

/**
 * <p>Title: JM 整合Swing控件，使用配置信息</p>
 *
 * <p>Copyright: Copyright (c) 2004-2006</p>
 *
 * <p>Company: 1SHome</p>
 *
 * <p>@author Spook</p>
 *
 * @since 1.3
 * @see JDK 1.5.0.6
 */
public class JMGUIFileFilter extends FileFilter {
    @SuppressWarnings("unused")
	private static String TYPE_UNKNOWN = "Type Unknown";
    @SuppressWarnings("unused")
	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 JMGUIFileFilter() {
    this.filters = new Hashtable();
    }

    /**
     * Creates a file filter that accepts files with the given extension.
     * Example: new ExampleFileFilter("jpg");
     *
     * @see #addExtension
     */
    public JMGUIFileFilter(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 JMGUIFileFilter(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 JMGUIFileFilter(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 JMGUIFileFilter(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.
     */
    @SuppressWarnings("unchecked")
	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;
    }
}