bdsup2sub.tools.JFileFilter Maven / Gradle / Ivy
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/*
* Copyright 2014 Volker Oth (0xdeadbeef) / Miklos Juhasz (mjuhasz)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package bdsup2sub.tools;
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.
*/
public class JFileFilter extends FileFilter {
private Hashtable filters;
private String description;
private String fullDescription;
private boolean useExtensionsInDescription = true;
/**
* Creates a file filter. If no filters are added, then all
* files are accepted.
*
* @see #addExtension(String)
*/
public JFileFilter() {
this.filters = new Hashtable();
}
/**
* Creates a file filter that accepts files with the given extension.
* Example: new JFileFilter("jpg");
*
* @param extension string containing file extension
* @see #addExtension(String)
*/
public JFileFilter(String extension) {
this(extension, null);
}
/**
* Creates a file filter that accepts the given file type.
* Example: new JFileFilter("jpg", "JPEG Image Images");
*
* Note that the "." before the extension is not needed. If
* provided, it will be ignored.
*
* @param extension string containing file extension
* @param description string containing file description
*
* @see #addExtension(String)
*/
public JFileFilter(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 JFileFilter(String {"gif", "jpg"});
*
* Note that the "." before the extension is not needed adn
* will be ignored.
*
* @param filters string array containing extensions
*
* @see #addExtension(String)
*/
public JFileFilter(String[] filters) {
this(filters, null);
}
/**
* Creates a file filter from the given string array and description.
* Example: new JFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
*
* Note that the "." before the extension is not needed and will be ignored.
*
* @param filters string array containing extensions
* @param description string containing file description
*
* @see #addExtension(String)
*/
public JFileFilter(String[] filters, String description) {
this();
for (String filter : filters) {
// add filters one by one
addExtension(filter);
}
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(File)
* @see #accept(File)
*/
@Override
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(File)
* @see #accept(File)
* @param f File handle to get extension for
* @return extension as string (excluding the '.')
*/
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 file type "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":
*
* JFileFilter filter = new JFileFilter();
* filter.addExtension("jpg");
* filter.addExtension("tif");
*
* Note that the "." before the extension is not needed and will be ignored.
* @param extension file extension (e.g. '.sup')
*/
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(String)
* @see #setExtensionListInDescription(boolean)
* @see #isExtensionListInDescription()
* @see #getDescription()
*/
@Override
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 += "." + extensions.nextElement();
while (extensions.hasMoreElements()) {
fullDescription += ", ." + extensions.nextElement();
}
}
fullDescription += ")";
} else {
fullDescription = description;
}
}
return fullDescription;
}
/**
* Sets the human readable description of this filter. For
* example: filter.setDescription("Gif and JPG Images");
*
* @param description string containing file description
*
* @see #setDescription(String)
* @see #setExtensionListInDescription(boolean)
* @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 relevant if a description was provided in the constructor
* or using setDescription();
*
* @param b true if the extension list should show up in the human readable description
*
* @see #getDescription()
* @see #setDescription(String)
* @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 relevant if a description was provided in the constructor
* or using setDescription();
*
* @return true if the extension list should show up in the human readable description
*
* @see #getDescription()
* @see #setDescription(String)
* @see #setExtensionListInDescription(boolean)
*/
public boolean isExtensionListInDescription() {
return useExtensionsInDescription;
}
}
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