IgnoreClassHelper.java

package com.avaje.ebean.enhance.agent;

import java.util.HashMap;

/**
 * Helper object used to ignore known classes. We only want to enhance the
 * entity beans and perhaps some other user classes (not JDK classes etc).
 * <p>
 * In looking for classes to enhance we can skip some such as JDK, JDBC and
 * other known libraries.
 * </p>
 * <p>
 * The agentArgs can optionally include a "packages" parameter with a comma
 * delimited list of packages that SHOULD be processed. All other packages would
 * then be ignored.
 * </p>
 */
public class IgnoreClassHelper {

	private final String[] processPackages;

	public IgnoreClassHelper(String agentArgs) {

		HashMap<String, String> args = ArgParser.parse(agentArgs);
		String packages = args.get("packages");
		if (packages != null) {
			String[] pkgs = packages.split(",");
			processPackages = new String[pkgs.length];
			for (int i = 0; i < pkgs.length; i++) {
				processPackages[i] = convertPackage(pkgs[i]);
			}
		} else {
			processPackages = new String[0];
		}
	}

	/**
	 * Convert dots/periods to slashes in the package name.
	 */
	private String convertPackage(String pkg) {

		pkg = pkg.trim().replace('.', '/');

		if (pkg.endsWith("*")) {
			// wild card, remove the * ... and
			// don't add a "/" to the end
			return pkg.substring(0, pkg.length() - 1);

		} else if (pkg.endsWith("/")) {
			// already ends in "/"
			return pkg;

		} else {
			// add "/" so we don't pick up another
			// package with a similar starting name
			return pkg + "/";
		}
	}

	/**
	 * Use specific positive matching to determine if the class needs to be
	 * processed.
	 * <p>
	 * Any class at any depth under the package can be processed and all others
	 * ignored.
	 * </p>
	 * 
	 * @return true if the class can be ignored
	 */
	private boolean specificMatching(String className) {

		for (int i = 0; i < processPackages.length; i++) {
			if (className.startsWith(processPackages[i])) {
				// a positive match
				return false;
			}
		}
		// we can ignore this class
		return true;
	}

	/**
	 * Try to exclude JDK classes and known JDBC Drivers and Libraries.
	 * <p>
	 * We want to do this for performance reasons - that is skip checking for
	 * enhancement on classes that we know are not part of the application code
	 * and should not be enhanced.
	 * </p>
	 * 
	 * @param className
	 *            the className of the class being defined.
	 * @return true if this class should not be processed.
	 */
	public boolean isIgnoreClass(String className) {
		
		className = className.replace('.', '/');
		
		// the special entity beans supplied by Ebean SHOULD be processed
		if (className.startsWith(EnhanceConstants.EBEAN_META_PREFIX)) {
			return false;
		}

		if (processPackages.length > 0) {
			// use specific positive matching
			return specificMatching(className);
		}
		
		// we don't have specific packages to process so instead 
		// we will ignore packages that we know we don't want to
		// process (they won't contain entity beans etc).

		// the rest of Ebean should be ignored
		if (className.startsWith(EnhanceConstants.EBEAN_PREFIX)) {
			return true;
		}
		// ignore the JDK classes ...
		if (className.startsWith("java/") || className.startsWith("javax/")) {
			return true;
		}
		if (className.startsWith("sun/") || className.startsWith("sunw/") || className.startsWith("com/sun/")) {
			return true;
		}
		if (className.startsWith("org/wc3/") || className.startsWith("org/xml/")) {
			return true;
		}
		if (className.startsWith("org/junit/") || className.startsWith("junit/")) {
			return true;
		}
		// ignore apache libraries
		if (className.startsWith("org/apache/")) {
			return true;
		}
		if (className.startsWith("org/eclipse/")) {
			return true;
		}
        if (className.startsWith("org/joda/")) {
            return true;
        }		
        // ignore mysql jdbc drivers
		if (className.startsWith("com/mysql/jdbc")) {
			return true;
		}
		// ignore postgres jdbc drivers
        if (className.startsWith("org/postgresql/")) {
            return true;
        }
		// ignore h2
		if (className.startsWith("org/h2/")) {
			return true;
		}
		// ignore oracle
		if (className.startsWith("oracle/")) {
			return true;
		}
		// ignore base groovy classes
		if (className.startsWith("groovy/")) {
			return true;
		}
		// ignore $Proxy classes
		if (className.startsWith("$")) {
			return true;
		}
		return false;
	}
}