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The AspectJ matcher can be used for matching pointcuts independently of any AspectJ compilation or weaving steps. Most notably, this can be used by frameworks such as Spring AOP which utilise the @AspectJ pointcut syntax but implement aspect weaving in a way independent of AspectJ, e.g. using dynamic proxies.

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/* *******************************************************************
 * Copyright (c) 2003 Contributors.
 * All rights reserved.
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Public License v 2.0
 * which accompanies this distribution and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.txt
 *
 * Contributors:
 *     Isberg        initial implementation
 * ******************************************************************/

package org.aspectj.util;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

/**
 * Load classes as File from File[] dirs or URL[] jars.
 */
public class UtilClassLoader extends URLClassLoader {

    /** seek classes in dirs first */
    List dirs;

    /** save URL[] only for toString */
    private URL[] urlsForDebugString;

    public UtilClassLoader(URL[] urls, File[] dirs) {
        super(urls);
        LangUtil.throwIaxIfNotAssignable(dirs, File.class, "dirs");
        this.urlsForDebugString = urls;
        List dcopy = new ArrayList<>();

        if (!LangUtil.isEmpty(dirs)) {
            dcopy.addAll(Arrays.asList(dirs));
        }
        this.dirs = Collections.unmodifiableList(dcopy);
    }


    public URL getResource(String name) {
        return ClassLoader.getSystemResource(name);
    }

    public InputStream getResourceAsStream(String name) {
        return ClassLoader.getSystemResourceAsStream(name);
    }

    public synchronized Class loadClass(String name, boolean resolve)
        throws ClassNotFoundException {
        // search the cache, our dirs (if maybe test),
        // the system, the superclass (URL[]),
        // and our dirs again (if not maybe test)
        ClassNotFoundException thrown = null;
        Class result =  findLoadedClass(name);
        if (null != result) {
            resolve = false;
        } else {
            try {
                result = findSystemClass(name);
            } catch (ClassNotFoundException e) {
                thrown = e;
            }
        }
        if (null == result) {
            try {
                result = super.loadClass(name, resolve);
            } catch (ClassNotFoundException e) {
                thrown = e;
            }
            if (null != result) { // resolved by superclass
                return result;
            }
        }
        if (null == result) {
            byte[] data = readClass(name);
            if (data != null) {
                result = defineClass(name, data, 0, data.length);
            } // handle ClassFormatError?
        }

        if (null == result) {
            throw (null != thrown ? thrown : new ClassNotFoundException(name));
        }
        if (resolve) {
            resolveClass(result);
        }
        return result;
    }

    /** @return null if class not found or byte[] of class otherwise */
    private byte[] readClass(String className) throws ClassNotFoundException {
        final String fileName = className.replace('.', '/')+".class";
		for (File dir : dirs) {
			File file = new File(dir, fileName);
			if (file.canRead()) {
				return getClassData(file);
			}
		}
        return null;
    }

    private byte[] getClassData(File f) {
        try {
            FileInputStream stream= new FileInputStream(f);
            ByteArrayOutputStream out= new ByteArrayOutputStream(1000);
            byte[] b= new byte[4096];
            int n;
            while ((n= stream.read(b)) != -1) {
                out.write(b, 0, n);
            }
            stream.close();
            out.close();
            return out.toByteArray();
        } catch (IOException e) {
        }
        return null;
    }

    /** @return String with debug info: urls and classes used */
    public String toString() {
        return "UtilClassLoader(urls="
            + Arrays.asList(urlsForDebugString)
            + ", dirs="
            + dirs
            + ")";
    }
}