context.java

java中比较著名的js引擎当属mozilla开源的rhino

     * Get the implementation version.
     *
     * <p>
     * The implementation version is of the form
     * <pre>
     *    "<i>name langVer</i> <code>release</code> <i>relNum date</i>"
     * </pre>
     * where <i>name</i> is the name of the product, <i>langVer</i> is
     * the language version, <i>relNum</i> is the release number, and
     * <i>date</i> is the release date for that specific
     * release in the form "yyyy mm dd".
     *
     * @return a string that encodes the product, language version, release
     *         number, and date.
     */
    public final String getImplementationVersion()
    {
        // XXX Probably it would be better to embed this directly into source
        // with special build preprocessing but that would require some ant
        // tweaking and then replacing token in resource files was simpler
        if (implementationVersion == null) {
            implementationVersion
                = ScriptRuntime.getMessage0("implementation.version");
        }
        return implementationVersion;
    }

    /**
     * Get the current error reporter.
     *
     * @see org.mozilla.javascript.ErrorReporter
     */
    public final ErrorReporter getErrorReporter()
    {
        if (errorReporter == null) {
            return DefaultErrorReporter.instance;
        }
        return errorReporter;
    }

    /**
     * Change the current error reporter.
     *
     * @return the previous error reporter
     * @see org.mozilla.javascript.ErrorReporter
     */
    public final ErrorReporter setErrorReporter(ErrorReporter reporter)
    {
        if (sealed) onSealedMutation();
        if (reporter == null) throw new IllegalArgumentException();
        ErrorReporter old = getErrorReporter();
        if (reporter == old) {
            return old;
        }
        Object listeners = propertyListeners;
        if (listeners != null) {
            firePropertyChangeImpl(listeners, errorReporterProperty,
                                   old, reporter);
        }
        this.errorReporter = reporter;
        return old;
    }

    /**
     * Get the current locale.  Returns the default locale if none has
     * been set.
     *
     * @see java.util.Locale
     */

    public final Locale getLocale()
    {
        if (locale == null)
            locale = Locale.getDefault();
        return locale;
    }

    /**
     * Set the current locale.
     *
     * @see java.util.Locale
     */
    public final Locale setLocale(Locale loc)
    {
        if (sealed) onSealedMutation();
        Locale result = locale;
        locale = loc;
        return result;
    }

    /**
     * Register an object to receive notifications when a bound property
     * has changed
     * @see java.beans.PropertyChangeEvent
     * @see #removePropertyChangeListener(java.beans.PropertyChangeListener)
     * @param l the listener
     */
    public final void addPropertyChangeListener(PropertyChangeListener l)
    {
        if (sealed) onSealedMutation();
        propertyListeners = Kit.addListener(propertyListeners, l);
    }

    /**
     * Remove an object from the list of objects registered to receive
     * notification of changes to a bounded property
     * @see java.beans.PropertyChangeEvent
     * @see #addPropertyChangeListener(java.beans.PropertyChangeListener)
     * @param l the listener
     */
    public final void removePropertyChangeListener(PropertyChangeListener l)
    {
        if (sealed) onSealedMutation();
        propertyListeners = Kit.removeListener(propertyListeners, l);
    }

    /**
     * Notify any registered listeners that a bounded property has changed
     * @see #addPropertyChangeListener(java.beans.PropertyChangeListener)
     * @see #removePropertyChangeListener(java.beans.PropertyChangeListener)
     * @see java.beans.PropertyChangeListener
     * @see java.beans.PropertyChangeEvent
     * @param  property  the bound property
     * @param  oldValue  the old value
     * @param  newVale   the new value
     */
    final void firePropertyChange(String property, Object oldValue,
                                  Object newValue)
    {
        Object listeners = propertyListeners;
        if (listeners != null) {
            firePropertyChangeImpl(listeners, property, oldValue, newValue);
        }
    }

    private void firePropertyChangeImpl(Object listeners, String property,
                                        Object oldValue, Object newValue)
    {
        for (int i = 0; ; ++i) {
            Object l = Kit.getListener(listeners, i);
            if (l == null)
                break;
            if (l instanceof PropertyChangeListener) {
                PropertyChangeListener pcl = (PropertyChangeListener)l;
                pcl.propertyChange(new PropertyChangeEvent(
                    this, property, oldValue, newValue));
            }
        }
    }

    /**
     * Report a warning using the error reporter for the current thread.
     *
     * @param message the warning message to report
     * @param sourceName a string describing the source, such as a filename
     * @param lineno the starting line number
     * @param lineSource the text of the line (may be null)
     * @param lineOffset the offset into lineSource where problem was detected
     * @see org.mozilla.javascript.ErrorReporter
     */
    public static void reportWarning(String message, String sourceName,
                                     int lineno, String lineSource,
                                     int lineOffset)
    {
        Context cx = Context.getContext();
        cx.getErrorReporter().warning(message, sourceName, lineno,
                                      lineSource, lineOffset);
    }

    /**
     * Report a warning using the error reporter for the current thread.
     *
     * @param message the warning message to report
     * @see org.mozilla.javascript.ErrorReporter
     */
    public static void reportWarning(String message)
    {
        int[] linep = { 0 };
        String filename = getSourcePositionFromStack(linep);
        Context.reportWarning(message, filename, linep[0], null, 0);
    }

    /**
     * Report an error using the error reporter for the current thread.
     *
     * @param message the error message to report
     * @param sourceName a string describing the source, such as a filename
     * @param lineno the starting line number
     * @param lineSource the text of the line (may be null)
     * @param lineOffset the offset into lineSource where problem was detected
     * @see org.mozilla.javascript.ErrorReporter
     */
    public static void reportError(String message, String sourceName,
                                   int lineno, String lineSource,
                                   int lineOffset)
    {
        Context cx = getCurrentContext();
        if (cx != null) {
            cx.getErrorReporter().error(message, sourceName, lineno,
                                        lineSource, lineOffset);
        } else {
            throw new EvaluatorException(message, sourceName, lineno,
                                         lineSource, lineOffset);
        }
    }

    /**
     * Report an error using the error reporter for the current thread.
     *
     * @param message the error message to report
     * @see org.mozilla.javascript.ErrorReporter
     */
    public static void reportError(String message)
    {
        int[] linep = { 0 };
        String filename = getSourcePositionFromStack(linep);
        Context.reportError(message, filename, linep[0], null, 0);
    }

    /**
     * Report a runtime error using the error reporter for the current thread.
     *
     * @param message the error message to report
     * @param sourceName a string describing the source, such as a filename
     * @param lineno the starting line number
     * @param lineSource the text of the line (may be null)
     * @param lineOffset the offset into lineSource where problem was detected
     * @return a runtime exception that will be thrown to terminate the
     *         execution of the script
     * @see org.mozilla.javascript.ErrorReporter
     */
    public static EvaluatorException reportRuntimeError(String message,
                                                        String sourceName,
                                                        int lineno,
                                                        String lineSource,
                                                        int lineOffset)
    {
        Context cx = getCurrentContext();
        if (cx != null) {
            return cx.getErrorReporter().
                            runtimeError(message, sourceName, lineno,
                                         lineSource, lineOffset);
        } else {
            throw new EvaluatorException(message, sourceName, lineno,
                                         lineSource, lineOffset);
        }
    }

    static EvaluatorException reportRuntimeError0(String messageId)
    {
        String msg = ScriptRuntime.getMessage0(messageId);
        return reportRuntimeError(msg);
    }

    static EvaluatorException reportRuntimeError1(String messageId,
                                                  Object arg1)
    {
        String msg = ScriptRuntime.getMessage1(messageId, arg1);
        return reportRuntimeError(msg);
    }

    static EvaluatorException reportRuntimeError2(String messageId,
                                                  Object arg1, Object arg2)
    {
        String msg = ScriptRuntime.getMessage2(messageId, arg1, arg2);
        return reportRuntimeError(msg);
    }

    static EvaluatorException reportRuntimeError3(String messageId,
                                                  Object arg1, Object arg2,
                                                  Object arg3)
    {
        String msg = ScriptRuntime.getMessage3(messageId, arg1, arg2, arg3);
        return reportRuntimeError(msg);
    }

    static EvaluatorException reportRuntimeError4(String messageId,
                                                  Object arg1, Object arg2,
                                                  Object arg3, Object arg4)
    {
        String msg
            = ScriptRuntime.getMessage4(messageId, arg1, arg2, arg3, arg4);
        return reportRuntimeError(msg);
    }

    /**
     * Report a runtime error using the error reporter for the current thread.
     *
     * @param message the error message to report
     * @see org.mozilla.javascript.ErrorReporter
     */
    public static EvaluatorException reportRuntimeError(String message)
    {
        int[] linep = { 0 };
        String filename = getSourcePositionFromStack(linep);
        return Context.reportRuntimeError(message, filename, linep[0], null, 0);
    }

    /**
     * Initialize the standard objects.
     *
     * Creates instances of the standard objects and their constructors
     * (Object, String, Number, Date, etc.), setting up 'scope' to act
     * as a global object as in ECMA 15.1.<p>
     *
     * This method must be called to initialize a scope before scripts
     * can be evaluated in that scope.<p>
     *
     * This method does not affect the Context it is called upon.
     *
     * @return the initialized scope
     */
    public final ScriptableObject initStandardObjects()
    {
        return initStandardObjects(null, false);
    }

    /**
     * Initialize the standard objects.
     *
     * Creates instances of the standard objects and their constructors
     * (Object, String, Number, Date, etc.), setting up 'scope' to act
     * as a global object as in ECMA 15.1.<p>
     *
     * This method must be called to initialize a scope before scripts
     * can be evaluated in that scope.<p>
     *
     * This method does not affect the Context it is called upon.
     *
     * @param scope the scope to initialize, or null, in which case a new
     *        object will be created to serve as the scope
     * @return the initialized scope. The method returns the value of the scope
     *         argument if it is not null or newly allocated scope object which
     *         is an instance {@link ScriptableObject}.
     */
    public final Scriptable initStandardObjects(ScriptableObject scope)
    {
        return initStandardObjects(scope, false);
    }

    /**
     * Initialize the standard objects.
     *
     * Creates instances of the standard objects and their constructors
     * (Object, String, Number, Date, etc.), setting up 'scope' to act
     * as a global object as in ECMA 15.1.<p>
     *
     * This method must be called to initialize a scope before scripts
     * can be evaluated in that scope.<p>
     *
     * This method does not affect the Context it is called upon.<p>
     *
     * This form of the method also allows for creating "sealed" standard
     * objects. An object that is sealed cannot have properties added, changed,
     * or removed. This is useful to create a "superglobal" that can be shared
     * among several top-level objects. Note that sealing is not allowed in
     * the current ECMA/ISO language specification, but is likely for
     * the next version.
     *
     * @param scope the scope to initialize, or null, in which case a new
     *        object will be created to serve as the scope
     * @param sealed whether or not to create sealed standard objects that
     *        cannot be modified.