www.pudn.com > use-2.3.0.zip > USEMonitor.java.template

// -*- mode: java -*-
@FILE_HEADER@

package org.tzi.use.monitor;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.reflect.SourceLocation;
import java.net.Socket;
import java.io.PrintWriter;
import java.io.IOException;
import java.util.Set;
import java.util.IdentityHashMap;

/**
 * Interface to be implemented (by introduction) by all monitored
 * classes. This maps every monitored java object to a unique USE
 * object.
 */
interface USEObject {
    int getUSEId();
    void setUSEId(int id);
}

aspect USEMonitor {
    /**
     * Set to true if source location should be output as comments in
     * USE commands.
     */
    private static final boolean LOG_LOCATION = false;

    // --- introductions

    /**
     * Let all observed classes implement the interface USEObject.
     */
    declare parents: (
@INTRODUCTION_PARENTS@
        ) implements USEObject;

    /**
     * Adds a private ID field to every class that is used to assign 
     * every new object a unique identifier. This identifier maps USE 
     * objects to Java objects and vice versa.
     */
    private int (
@INTRODUCTION_USEID_FIELD@
        ).fUSEId;

    /**
     * Returns the unique ID of an object. Implements the interface 
     * USEObject.
     */
    public int (
@INTRODUCTION_USEID_GETTER@
        ).getUSEId() { return fUSEId; }

    /**
     * Sets the unique ID of an object. Implements the interface 
     * USEObject.
     */
    public void (
@INTRODUCTION_USEID_SETTER@
        ).setUSEId(int id) { fUSEId = id; }


    // --- pointcuts

    /**
     * Monitored classes.
     */
    pointcut pcClass() :
@POINTCUT_CLASS@
        ;

    /**
     * The constructors of monitored classes.
     */
    pointcut pcConstructor(Object _this) :
        this(_this) && pcClass() && execution(new(..));

    /**
     * The methods of monitored classes.
     */
    pointcut pcMethod(Object t) :
        target(t) && pcClass() && (
@POINTCUT_METHOD@
	);

    /**
     * The field setters of monitored classes.
     */
    pointcut pcSetter(Object t, Object _args) :
        target(t) && pcClass() && args(_args) && (
@POINTCUT_SETTER@
        );


//     /**
//      * Calls to add methods on collections.
//      */
//     pointcut pcSetAdd(Object o, Company _this, Object _who) : 
// 	monitoredClass() && target(o) && this(_this)
// 	&& call(* *.add(Object)) 
// 	&& args(_who);

//     /**
//      * Calls to remove methods on collections.
//      */
//     pointcut pcSetRemove(Object o, Company _this, Object _who) : 
// 	monitoredClass() && target(o) && this(_this) 
// 	&& call(* *.remove(Object)) && args(_who);

    // --- advices

    /**
     * Monitor object creation.
     */
    before (Object _this) : pcConstructor(_this) {
        logLocation(thisJoinPoint, "before constructor execution");

        // assign object a unique ID for identification in USE
	USEObject uobj = (USEObject) _this;
	// object may already have an ID when the constructor of a
	// super class has been called before
	if ( uobj.getUSEId() > 0 )
	    return;

	uobj.setUSEId(fNextId++);

	// strip off package name
	String classname = thisJoinPoint.getTarget().getClass().getName();
	int n = classname.lastIndexOf('.');
	if ( n >= 0 && n < classname.length() - 1 )
	    classname = classname.substring(n + 1);
        log("!create " + getUSEObjectName(_this) + " : " + classname);
    }

    after(Object t) : pcConstructor(t) {
        logLocation(thisJoinPoint, "after constructor execution");
        log("check");
    }

    /**
     * Monitor method execution.
     */
    before (Object t) : pcMethod(t) {
        logLocation(thisJoinPoint, "before method execution");
	Object[] args = thisJoinPoint.getArgs();
	StringBuffer sargs = new StringBuffer();
	for (int i = 0; i < args.length; i++) {
	    if ( i > 0 )
		sargs.append(", ");
	    if ( args[i] instanceof USEObject ) {
		int oid = ((USEObject) args[i]).getUSEId();
		sargs.append("obj" + oid);
	    } else if ( args[i] instanceof String ) 
		sargs.append("'" + args[i] + "'");
	    else 
		sargs.append(args[i]);
	}

	String methodName = thisJoinPoint.getSignature().getName();
        log("!openter " + getUSEObjectName(t) + " " + methodName + "(" + sargs + ")");
    }

    after(Object t) returning (Object retVal) : pcMethod(t) {
        logLocation(thisJoinPoint, "after method execution");
        log("!opexit " + (( retVal == null ) ? "" : retVal));
    }

    /**
     * Trace field setters.
     */
    after(Object t, Object newValue) : pcSetter(t, newValue) {
        logLocation(thisJoinPoint, "setting field");
	String value = newValue.toString();
	if ( newValue instanceof String ) 
	    value = "'" + value + "'";

	String attrName = thisJoinPoint.getSignature().getName();
	// filter assignments to fields related to associations
	// FIXME: generalize
	if ( ! attrName.equals("employee") )
	     log("!set " + getUSEObjectName(t) + "." + attrName + " := " + value);
	else 
	    fFields.put(newValue, attrName);
    }

//     /**
//      * Insert association links.
//      */
//     after(Object o, Company _this, Object _who) : pcSetAdd(o, _this, _who) {
//         logLocation(thisJoinPoint, "adding link");
// 	if ( fFields.containsKey(o) ) {
// 	    log("!insert (" 
// 		+ getUSEObjectName(_who) + ", " 
// 		+ getUSEObjectName(_this) 
// 		+ ") into WorksFor");
// 	}

//     }


//     /**
//      * Insert association links.
//      */
//     after(Object o, Company _this, Object _who) : pcSetRemove(o, _this, _who) {
//         logLocation(thisJoinPoint, "removing link");
// 	if ( fFields.containsKey(o) ) {
// 	    log("!delete (" 
// 		+ getUSEObjectName(_who) + ", " 
// 		+ getUSEObjectName(_this) 
// 		+ ") from WorksFor");
// 	}

//     }


//     after(Object o) : pcSetGetter(o) {
//         logLocation(thisJoinPoint, "----------------- pcSetGetter");
//         log("* " + o + ", " + thisJoinPoint.getSignature());
//     }


    /**
     * The next unique ID assigned to a new object.
     */
    private static int fNextId = 1;
    
    /**
     * Map of field values to field names. Used for identifying
     * modifications of association elements.
     */
    private IdentityHashMap fFields = new IdentityHashMap(); // (Object -> String fieldname)

    // helpers

    private String getUSEObjectName(Object obj) {
	int id = ((USEObject) obj).getUSEId();
	return "obj" + id;
    } 

    private void logLocation(JoinPoint jp, String msg) {
	if ( LOG_LOCATION ) {
	    SourceLocation loc = jp.getSourceLocation();
	    log("-- " + loc.getFileName() + ":" + loc.getLine() + ": " + msg);
	}
    }

    private Socket fSocket;
    private boolean fInitDone;
    private PrintWriter fOut;
    
    /**
     * Initializes a  socket connection to USE.
     */
    private void initSocket() {
	fInitDone = true;
	try {
	    fSocket = new Socket("localhost", 1777);
	    // flush after each line of output
	    fOut = new PrintWriter(fSocket.getOutputStream(), true);
	} catch (IOException ex) {
	    System.err.println("can't connect to localhost/1777: " + ex.getMessage());
	    if ( fSocket != null ) {
		try {
		    fSocket.close();
		} catch (IOException e) { }
	    }
	}
    }

    /**
     * Outputs commands either to socket or stdout
     */
    private void log(String msg) {
	if ( fSocket == null && ! fInitDone )
	    initSocket();
	if ( fOut != null ) {
	    fOut.println(msg);
	} else {
	    System.out.println(msg);
	}
    }
}