classdescriptor.java

A static analysis tool to find bugs in Java programs

/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2006, University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.classfile;

import java.io.Serializable;

import edu.umd.cs.findbugs.util.ClassName;

/**
 * Descriptor identifying a class.
 * 
 * @author David Hovemeyer
 */
public class ClassDescriptor implements Comparable<ClassDescriptor>, Serializable {
	private static final long serialVersionUID = 1L;
	private final String className;

	/**
	 * Constructor.
	 * 
	 * @param className class name in VM format, e.g. "java/lang/String"
	 */
	public ClassDescriptor(String className) {
		if (className.indexOf('.') >= 0) {
			throw new IllegalArgumentException("Class name " + className + " not in VM format");
		}
		if (!ClassName.isValidClassName(className)) {
			throw new IllegalArgumentException("Invalid class name " + className);
		}
		this.className = className;
	}

	/**
	 * @return Returns the class name in VM format, e.g. "java/lang/String"
	 */
	public String getClassName() {
		return className;
	}

	/* (non-Javadoc)
	 * @see java.lang.Comparable#compareTo(java.lang.Object)
	 */
	public int compareTo(ClassDescriptor o) {
		return className.compareTo(o.className);
	}

	/**
	 * Get the resource name of this class as it would appear in the classpath.
	 * E.g., "java/lang/String.class"
	 * 
	 * @return the resource name
	 */
	public String toResourceName() {
		return className + ".class";
	}

	/**
	 * Get the name of the class in dotted format.
	 * 
	 * @return the name of the class in dotted format
	 */
	public String toDottedClassName() {
		return ClassName.toDottedClassName(className);
	}

	/**
	 * Create a class descriptor from a resource name.
	 * 
	 * @param resourceName the resource name
	 * @return the class descriptor
	 */
	public static ClassDescriptor fromResourceName(String resourceName) {
		if (!isClassResource(resourceName)) {
			throw new IllegalArgumentException("Resource " + resourceName + " is not a class");
		}
		return new ClassDescriptor(resourceName.substring(0, resourceName.length() - 6));
	}

	/**
	 * Determine whether or not the given resource name refers to a class.
	 * 
	 * @param resourceName the resource name
	 * @return true if the resource is a class, false otherwise
	 */
	public static boolean isClassResource(String resourceName) {
		// This could be more sophisticated.
		return resourceName.endsWith(".class");
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return className;
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(Object obj) {
		if (obj == null || obj.getClass() != this.getClass()) {
			return false;
		}
		ClassDescriptor other = (ClassDescriptor) obj;
		return this.className.equals(other.className);
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {
		return className.hashCode();
	}
}