examplefilefilter.java

自己写的汉诺塔java程序。通过调用ShowHanoiFrame开启主界面及可运行程序。软件语言java

package TowersOfHanoi;

import java.io.File;
import java.util.*;
import javax.swing.filechooser.*;
import java.io.Serializable;

//过滤文件类型的类
public class ExampleFileFilter extends FileFilter implements Serializable{

    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;

    public ExampleFileFilter() {
        this.filters = new Hashtable();
    }

    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;
    }

     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;
    }

    public void addExtension(String extension) {
        if(filters == null) {
            filters = new Hashtable(5);
        }
        filters.put(extension.toLowerCase(), this);
        fullDescription = null;
    }

    public String getDescription() {
        if(fullDescription == null) {
            if(description == null || isExtensionListInDescription()) {
                fullDescription = description==null ? "(" : description + " (";
                Enumeration extensions = filters.keys();
                if(extensions != null) {
                    fullDescription += "." + (String) extensions.nextElement();
                    while (extensions.hasMoreElements()) {
                        fullDescription += ", ." + (String) extensions.nextElement();
                    }
                }
                fullDescription += ")";
            } else {
                fullDescription = description;
            }
        }
        return fullDescription;
    }

    public void setDescription(String description) {
        this.description = description;
        fullDescription = null;
    }

    public void setExtensionListInDescription(boolean b) {
        useExtensionsInDescription = b;
        fullDescription = null;
    }

    public boolean isExtensionListInDescription() {
        return useExtensionsInDescription;
    }
}