/*
* This file is part of muCommander, http://www.mucommander.com
* Copyright (C) 2002-2016 Maxence Bernard
*
* muCommander is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* muCommander is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.mucommander.extension;
import java.io.IOException;
import java.util.List;
import java.util.Vector;
import com.mucommander.commons.file.AbstractFile;
import com.mucommander.commons.file.AbstractFileClassLoader;
import com.mucommander.commons.file.filter.AttributeFileFilter;
import com.mucommander.commons.file.filter.AttributeFileFilter.FileAttribute;
import com.mucommander.commons.file.filter.ExtensionFilenameFilter;
import com.mucommander.commons.file.filter.OrFileFilter;
/**
* Finds specific classes within a browsable file.
* <p>
* This class will explore the content of a browsable {@link com.mucommander.commons.file.AbstractFile} and match
* all discovered classes to a {@link ClassFilter}.
* </p>
* <p>
* In order for classes to be analyzed, they need to be loaded. This can be achieved in two ways:
* <ul>
* <li>By using a custom class loader through {@link #find(AbstractFile,ClassFilter,ClassLoader)}.</li>
* <li>
* By using an {@link com.mucommander.commons.file.AbstractFileClassLoader}
* </ul>
* </p>
* @author Nicolas Rinaudo
*/
public class ClassFinder {
// - Instance fields -----------------------------------------------------------------
// -----------------------------------------------------------------------------------
/** ClassLoader used to load classes from explored files. */
private ClassLoader loader;
/** Used to filter out files that are neither classes nor directories. */
private OrFileFilter filter;
/** Used to filter out unwanted classes. */
private ClassFilter classFilter;
// - Initialization ------------------------------------------------------------------
// -----------------------------------------------------------------------------------
/**
* Creates a new instance of <code>ClassFinder</code>.
*/
public ClassFinder() {
filter = new OrFileFilter(
new ExtensionFilenameFilter(".class"),
new AttributeFileFilter(FileAttribute.DIRECTORY)
);
}
// - File exploring ------------------------------------------------------------------
// -----------------------------------------------------------------------------------
/**
* Explores the specified file for classes that match {@link #classFilter}.
* @param currentPackage package we're currently exploring (with a trailing '.').
* @param currentFile file we're currently exploring.
* @return a vector containing all the classes that were found and matched <code>classFilter</code>.
* @throws IOException if an error occurs while exploring <code>currentFile</code>.
*/
private List<Class<?>> find(String currentPackage, AbstractFile currentFile) throws IOException {
AbstractFile[] files; // All subfolders or child class files of currentFile.
Class<?> currentClass; // Buffer for the current class.
List<Class<?>> result = new Vector<Class<?>>();
// Analyses all subdirectories and class files.
files = currentFile.ls(filter);
for (AbstractFile file : files) {
// Explores subdirectories recursively.
if (file.isDirectory())
result.addAll(find(currentPackage + file.getName() + '.', file));
// Passes each class through the class filter.
// Errors are treated as 'this class is not wanted'.
else {
try {
if (classFilter.accept(currentClass = Class.forName(currentPackage + file.getNameWithoutExtension(), false, loader)))
result.add(currentClass);
}
catch (Throwable e) {
}
}
}
return result;
}
// - Public code ---------------------------------------------------------------------
// -----------------------------------------------------------------------------------
/**
* Explores the content of the specified file and looks for classes that match the specified class filter.
* <p>
* The <code>browsable</code> argument must be browsable as defined by {@link com.mucommander.commons.file.AbstractFile#isBrowsable()}.
* If such is not the case, the returned vector will be empty.
* </p>
* @param browsable file in which to look for classes.
* @param classFilter how to decide which classes should be kept.
* @param classLoader used to load each class found in <code>browsable</code>.
* @return a vector containing all the classes that were found and matched <code>classFilter</code>.
* @throws IOException if an error occurs while exploring <code>browsable</code>.
* @see #find(AbstractFile,ClassFilter)
*/
public List<Class<?>> find(AbstractFile browsable, ClassFilter classFilter, ClassLoader classLoader) throws IOException {
// Ignore non-browsable files.
if(!browsable.isBrowsable())
return new Vector<Class<?>>();
// Initializes exploring.
loader = classLoader;
this.classFilter = classFilter;
// Looks for all matched classes in browsable.
return find("", browsable);
}
/**
* Explores the content of the specified file and looks for classes that match the specified class filter.
* <p>
* This is a convenience method and is strictly equivalent to calling {@link #find(AbstractFile,ClassFilter,ClassLoader)}
* with a class loader argument initialized with the following code:
* <pre>
* AbstractFileClassLoader loader;
*
* loader = new AbstractFileClassLoader();
* loader.addFile(browsable);
* </pre>
* </p>
* @param browsable file in which to look for classes.
* @param classFilter how to decide which classes should be kept.
* @return a vector containing all the classes that were found and matched <code>classFilter</code>.
* @throws IOException if an error occurs while exploring <code>browsable</code>.
*/
public List<Class<?>> find(AbstractFile browsable, ClassFilter classFilter) throws IOException {
AbstractFileClassLoader classLoader; // Default class loader.
// Initializes the default class loader.
classLoader = new AbstractFileClassLoader();
classLoader.addFile(browsable);
// Explores browsable.
return find(browsable, classFilter, classLoader);
}
}