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/*******************************************************************************
*
* Copyright (c) 2004-2010 Oracle Corporation.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
*
*
*******************************************************************************/
package hudson.util;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.io.Serializable;
/**
* Visits files in a directory recursively.
*
* @since 1.343
* @see DirScanner
*/
public abstract class FileVisitor {
/**
* Called for each file and directory that matches the criteria implied by
* {@link DirScanner}
*
* @param f Either a file or a directory.
* @param relativePath The file/directory name in question
*/
public abstract void visit(File f, String relativePath) throws IOException;
/**
* Some visitors can handle symlinks as symlinks. Those visitors should
* implement this method to provide a different handling for symlink.
* This method is invoked by those {@link DirScanner}s that can handle
* symlinks as symlinks (not every {@link DirScanner}s are capable of doing
* that, as proper symlink handling requires letting visitors decide whether
* or not to descend into a symlink directory.
*/
public void visitSymlink(File link, String target, String relativePath) throws IOException {
visit(link, relativePath);
}
/**
* Some visitors can handle symlinks as symlinks. Those visitors should
* implement this method and return true to have callers invoke
* {@link #visitSymlink(File, String, String)}
*/
public boolean understandsSymlink() {
return false;
}
/**
* Decorates a visitor by a given filter.
*/
public final FileVisitor with(FileFilter f) {
if (f == null) {
return this;
}
return new FilterFileVisitor(f, this);
}
private static final class FilterFileVisitor extends FileVisitor implements Serializable {
private final FileFilter filter;
private final FileVisitor visitor;
private FilterFileVisitor(FileFilter filter, FileVisitor visitor) {
this.filter = filter != null ? filter : PASS_THROUGH;
this.visitor = visitor;
}
public void visit(File f, String relativePath) throws IOException {
if (f.isDirectory() || filter.accept(f)) {
visitor.visit(f, relativePath);
}
}
private static final FileFilter PASS_THROUGH = new FileFilter() {
public boolean accept(File pathname) {
return true;
}
};
private static final long serialVersionUID = 1L;
}
}