/*
 * @(#)TestClassParser.java
 */

package net.sourceforge.groboutils.junit.v1.parser;

import java.util.Vector;
import java.util.Enumeration;

import java.io.PrintWriter;
import java.io.StringWriter;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import junit.framework.TestSuite;
import junit.framework.TestCase;
import junit.framework.Test;

import org.apache.log4j.Logger;


/**
 * Parses Test classes to discover the usable test methods.
 * <P>
 * Ripped the test method discovery code out of junit.framework.TestSuite to
 * allow it to have usable logic.
 * <P>
 * This is not covered under the GroboUtils license, but rather under the
 * JUnit license (IBM Public License).  This heading may not be totally
 * in line with the license, so I'll change it when I find out what needs to
 * be changed.
 *
 * @author     Matt Albrecht <a href="mailto:groboclown@users.sourceforge.net">groboclown@users.sourceforge.net</a>
 * @version    $Date: 2002/11/05 00:49:31 $
 * @since      March 28, 2002
 */
public class TestClassParser
{
    private static final Logger LOG = Logger.getLogger(
        TestClassParser.class );
    
    private Class testClass;
    Vector testMethods = new Vector();
    private Vector warnings = new Vector();
    
    
    /**
     * The primary constructor, which will cause this instance to know how to
     * parse only the passed-in class.
     *
     * @param theClass the class to parse for testing.
     * @exception IllegalArgumentException if <tt>theClass</tt> is
     *      <tt>null</tt>.
     */
    public TestClassParser(final Class theClass)
    {
        if (theClass == null)
        {
            throw new IllegalArgumentException("no null arguments");
        }
        this.testClass = theClass;
        
        if (testClass( theClass ))
        {
            discoverTestMethods( theClass );
        }
    }
    
    
    //-------------------------------------------------------------------------
    // Public methods
    
    
    /**
     * Retrieve all warnings generated during the introspection of the class,
     * or test creation.  If a <tt>clearWarnings()</tt> call was ever made, then
     * only those warnings that were encountered after the call will be
     * returned.
     *
     * @return an array of all warnings generated while creating the test
     *      array.
     */
    public String[] getWarnings()
    {
        String w[] = new String[ this.warnings.size() ];
        this.warnings.copyInto( w );
        return w;
    }
    
    
    /**
     * Remove all current warnings.
     */
    public void clearWarnings()
    {
        this.warnings.removeAllElements();
    }
    
    
    /**
     * Retrieve all public test methods discovered through inspection.
     *
     * @return all test methods.
     */
    public Method[] getTestMethods()
    {
        Method m[] = new Method[ this.testMethods.size() ];
        this.testMethods.copyInto( m );
        return m;
    }
    
    
    /**
     * Get the name of the test suite.  By default, this is the class name.
     *
     * @return the name of the test suite.
     */
    public String getName()
    {
        return this.testClass.getName();
    }
    
    
    /**
     * Get the class under test.  This will never return <tt>null</tt>, and
     * will always match the class passed into the constructor.
     *
     * @return the class under test.
     */
    public Class getTestClass()
    {
        return this.testClass;
    }
    
    
    //-------------------------------------------------------------------------
    // Parse methods
    
    
    /**
     * Discover if the given class is a valid testing class.
     *
     * @param theClass the class to parse for testing.
     * @return <tt>true</tt> if the class is a public test class, otherwise
     *      <tt>false</tt>.
     */
    protected boolean testClass( final Class theClass )
    {
        boolean result = true;
        if (!Modifier.isPublic( theClass.getModifiers() ))
        {
            warning("Class " + theClass.getName() + " is not public.");
            result = false;
        }
        if (!Test.class.isAssignableFrom( theClass ))
        {
            warning("Class " + theClass.getName() +
                " does not implement "+Test.class.getName() );
            result = false;
        }
        return result;
    }
    
    
    /**
     * Discover and record the test methods of the public test class
     * <tt>theClass</tt>.
     *
     * @param theClass the class to parse for testing.
     */
    protected void discoverTestMethods( final Class theClass )
    {
        Class superClass = theClass;
        Vector names = new Vector();
        while (Test.class.isAssignableFrom( superClass ))
        {
            Method[] methods = superClass.getDeclaredMethods();
            for (int i = 0; i < methods.length; i++)
            {
                addTestMethod( methods[i], names );
            }
            superClass = superClass.getSuperclass();
        }
    }
    
    
    /**
     * Adds the method <tt>m</tt> to the inner list of known test methods,
     * but only if it is a public test method.
     *
     * @param m the method to add.
     * @param names a list of method names that have already been inspected.
     */
    protected void addTestMethod( Method m, Vector names )
    {
        String name = m.getName();
        if (names.contains(name) || this.testMethods.contains( m ))
        {
            return;
        }
        
        if (isPublicTestMethod(m))
        {
            names.addElement(name);

            this.testMethods.addElement( m );
        }
        else
        {
            // almost a test method
            if (isTestMethod(m))
            {
                warning("Test method isn't public: "+m.getName());
            }
        }
    }
    
    
    /**
     * Asserts that the method is public, and that it is also a test method.
     *
     * @param m the method under scrutiny.
     * @return <tt>true</tt> if <tt>m</tt> is a public test method, otherwise
     *      <tt>false</tt>.
     * @see #isTestMethod( Method )
     */
    protected boolean isPublicTestMethod( Method m )
    {
        return isTestMethod(m) && Modifier.isPublic(m.getModifiers());
    }
    
    /**
     * Test if method <tt>m</tt> is a test method, which means it accepts
     * no parameters, returns <tt>void</tt>, and the name of the method
     * begins with <tt>test</tt>.
     *
     * @param m the method under scrutiny.
     * @return <tt>true</tt> if <tt>m</tt> is a public test method, otherwise
     *      <tt>false</tt>.
     */
    protected boolean isTestMethod( Method m )
    {
        String name= m.getName();
        Class[] parameters= m.getParameterTypes();
        Class returnType= m.getReturnType();
        return parameters.length == 0 && name.startsWith("test") &&
            returnType.equals(Void.TYPE);
    }
    
    
    /**
     * Adds a warning message to the inner list of warnings.
     *
     * @param message the message describing the warning.
     */
    protected void warning( final String message )
    {
        LOG.debug( "WARNING: "+message );
        this.warnings.addElement( message );
    }
}