forwardconfig.java.svn-base

MVC开源框架

        this.catalog = catalog;
    }

    // ------------------------------------------------------ Protected Methods

    /**
     * <p>Traces the hierarchy of this object to check if any of the ancestors
     * are extending this instance.</p>
     *
     * @param moduleConfig The {@link ModuleConfig} that this config is from.
     * @param actionConfig The {@link ActionConfig} that this config is from,
     *                     if applicable.  This parameter must be null if this
     *                     forward config is a global forward.
     * @return true if circular inheritance was detected.
     */
    protected boolean checkCircularInheritance(ModuleConfig moduleConfig,
        ActionConfig actionConfig) {
        String ancestorName = getExtends();

        if (ancestorName == null) {
            return false;
        }

        // Find our ancestor
        ForwardConfig ancestor = null;

        // First check the action config
        if (actionConfig != null) {
            ancestor = actionConfig.findForwardConfig(ancestorName);

            // If we found *this*, set ancestor to null to check for a global def
            if (ancestor == this) {
                ancestor = null;
            }
        }

        // Then check the global forwards
        if (ancestor == null) {
            ancestor = moduleConfig.findForwardConfig(ancestorName);

            if (ancestor != null) {
                // If the ancestor is a global forward, set actionConfig
                //  to null so further searches are only done among
                //  global forwards.
                actionConfig = null;
            }
        }

        while (ancestor != null) {
            // Check if an ancestor is extending *this*
            if (ancestor == this) {
                return true;
            }

            // Get our ancestor's ancestor
            ancestorName = ancestor.getExtends();

            // check against ancestors extending same named ancestors
            if (ancestor.getName().equals(ancestorName)) {
                // If the ancestor is extending a config with the same name
                //  make sure we look for its ancestor in the global forwards.
                //  If we're already at that level, we return false.
                if (actionConfig == null) {
                    return false;
                } else {
                    // Set actionConfig = null to force us to look for global
                    //  forwards
                    actionConfig = null;
                }
            }

            ancestor = null;

            // First check the action config
            if (actionConfig != null) {
                ancestor = actionConfig.findForwardConfig(ancestorName);
            }

            // Then check the global forwards
            if (ancestor == null) {
                ancestor = moduleConfig.findForwardConfig(ancestorName);

                if (ancestor != null) {
                    // Limit further checks to moduleConfig.
                    actionConfig = null;
                }
            }
        }

        return false;
    }

    // --------------------------------------------------------- Public Methods

    /**
     * <p>Inherit values that have not been overridden from the provided
     * config object.  Subclasses overriding this method should verify that
     * the given parameter is of a class that contains a property it is trying
     * to inherit:</p>
     *
     * <pre>
     * if (config instanceof MyCustomConfig) {
     *     MyCustomConfig myConfig =
     *         (MyCustomConfig) config;
     *
     *     if (getMyCustomProp() == null) {
     *         setMyCustomProp(myConfig.getMyCustomProp());
     *     }
     * }
     * </pre>
     *
     * <p>If the given <code>config</code> is extending another object, those
     * extensions should be resolved before it's used as a parameter to this
     * method.</p>
     *
     * @param config The object that this instance will be inheriting its
     *               values from.
     * @see #processExtends(ModuleConfig, ActionConfig)
     */
    public void inheritFrom(ForwardConfig config)
        throws ClassNotFoundException, IllegalAccessException,
            InstantiationException, InvocationTargetException {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        // Inherit values that have not been overridden
        if (getCatalog() == null) {
            setCatalog(config.getCatalog());
        }

        if (getCommand() == null) {
            setCommand(config.getCommand());
        }

        if (getModule() == null) {
            setModule(config.getModule());
        }

        if (getName() == null) {
            setName(config.getName());
        }

        if (getPath() == null) {
            setPath(config.getPath());
        }

        if (!getRedirect()) {
            setRedirect(config.getRedirect());
        }

        inheritProperties(config);
    }

    /**
     * <p>Inherit configuration information from the ForwardConfig that this
     * instance is extending.  This method verifies that any forward config
     * object that it inherits from has also had its processExtends() method
     * called.</p>
     *
     * @param moduleConfig The {@link ModuleConfig} that this config is from.
     * @param actionConfig The {@link ActionConfig} that this config is from,
     *                     if applicable.  This must be null for global
     *                     forwards.
     * @see #inheritFrom(ForwardConfig)
     */
    public void processExtends(ModuleConfig moduleConfig,
        ActionConfig actionConfig)
        throws ClassNotFoundException, IllegalAccessException,
            InstantiationException, InvocationTargetException {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        String ancestorName = getExtends();

        if ((!extensionProcessed) && (ancestorName != null)) {
            ForwardConfig baseConfig = null;

            // We only check the action config if we're not a global forward
            boolean checkActionConfig =
                (this != moduleConfig.findForwardConfig(getName()));

            // ... and the action config was provided
            checkActionConfig &= (actionConfig != null);

            // ... and we're not extending a config with the same name
            // (because if we are, that means we're an action-level forward
            //  extending a global forward).
            checkActionConfig &= !ancestorName.equals(getName());

            // We first check in the action config's forwards
            if (checkActionConfig) {
                baseConfig = actionConfig.findForwardConfig(ancestorName);
            }

            // Then check the global forwards
            if (baseConfig == null) {
                baseConfig = moduleConfig.findForwardConfig(ancestorName);
            }

            if (baseConfig == null) {
                throw new NullPointerException("Unable to find " + "forward '"
                    + ancestorName + "' to extend.");
            }

            // Check for circular inheritance and make sure the base config's
            //  own extends have been processed already
            if (checkCircularInheritance(moduleConfig, actionConfig)) {
                throw new IllegalArgumentException(
                    "Circular inheritance detected for forward " + getName());
            }

            if (!baseConfig.isExtensionProcessed()) {
                baseConfig.processExtends(moduleConfig, actionConfig);
            }

            // copy values from the base config
            inheritFrom(baseConfig);
        }

        extensionProcessed = true;
    }

    /**
     * Return a String representation of this object.
     */
    public String toString() {
        StringBuffer sb = new StringBuffer("ForwardConfig[");

        sb.append("name=");
        sb.append(this.name);
        sb.append(",path=");
        sb.append(this.path);
        sb.append(",redirect=");
        sb.append(this.redirect);
        sb.append(",module=");
        sb.append(this.module);
        sb.append(",extends=");
        sb.append(this.inherit);
        sb.append(",catalog=");
        sb.append(this.catalog);
        sb.append(",command=");
        sb.append(this.command);
        sb.append("]");

        return (sb.toString());
    }
}