basehandlertag.java

structs源码

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

    /**
     * Return the text specified by the literal value or the message resources
     * key, if any; otherwise return <code>null</code>.
     *
     * @param literal Literal text value or <code>null</code>
     * @param key     Message resources key or <code>null</code>
     * @throws JspException if both arguments are non-null
     */
    protected String message(String literal, String key)
        throws JspException {
        if (literal != null) {
            if (key != null) {
                JspException e =
                    new JspException(messages.getMessage("common.both"));

                TagUtils.getInstance().saveException(pageContext, e);
                throw e;
            } else {
                return (literal);
            }
        } else {
            if (key != null) {
                return TagUtils.getInstance().message(pageContext, getBundle(),
                    getLocale(), key);
            } else {
                return null;
            }
        }
    }

    private Integer getJstlLoopIndex() {
        if (!triedJstlInit) {
            triedJstlInit = true;

            try {
                loopTagClass =
                    RequestUtils.applicationClass(
                        "javax.servlet.jsp.jstl.core.LoopTag");

                loopTagGetStatus =
                    loopTagClass.getDeclaredMethod("getLoopStatus", null);

                loopTagStatusClass =
                    RequestUtils.applicationClass(
                        "javax.servlet.jsp.jstl.core.LoopTagStatus");

                loopTagStatusGetIndex =
                    loopTagStatusClass.getDeclaredMethod("getIndex", null);

                triedJstlSuccess = true;
            } catch (ClassNotFoundException ex) {
                // These just mean that JSTL isn't loaded, so ignore
            } catch (NoSuchMethodException ex) {
            }
        }

        if (triedJstlSuccess) {
            try {
                Object loopTag =
                    findAncestorWithClass(this, loopTagClass);

                if (loopTag == null) {
                    return null;
                }

                Object status = loopTagGetStatus.invoke(loopTag, null);

                return (Integer) loopTagStatusGetIndex.invoke(status, null);
            } catch (IllegalAccessException ex) {
                log.error(ex.getMessage(), ex);
            } catch (IllegalArgumentException ex) {
                log.error(ex.getMessage(), ex);
            } catch (InvocationTargetException ex) {
                log.error(ex.getMessage(), ex);
            } catch (NullPointerException ex) {
                log.error(ex.getMessage(), ex);
            } catch (ExceptionInInitializerError ex) {
                log.error(ex.getMessage(), ex);
            }
        }

        return null;
    }

    /**
     * Appends bean name with index in brackets for tags with 'true' value in
     * 'indexed' attribute.
     *
     * @param handlers The StringBuffer that output will be appended to.
     * @throws JspException if 'indexed' tag used outside of iterate tag.
     */
    protected void prepareIndex(StringBuffer handlers, String name)
        throws JspException {
        if (name != null) {
            handlers.append(name);
        }

        handlers.append("[");
        handlers.append(getIndexValue());
        handlers.append("]");

        if (name != null) {
            handlers.append(".");
        }
    }

    /**
     * Returns the index value for tags with 'true' value in 'indexed'
     * attribute.
     *
     * @return the index value.
     * @throws JspException if 'indexed' tag used outside of iterate tag.
     */
    protected int getIndexValue()
        throws JspException {
        // look for outer iterate tag
        IterateTag iterateTag =
            (IterateTag) findAncestorWithClass(this, IterateTag.class);

        if (iterateTag != null) {
            return iterateTag.getIndex();
        }

        // Look for JSTL loops
        Integer i = getJstlLoopIndex();

        if (i != null) {
            return i.intValue();
        }

        // this tag should be nested in an IterateTag or JSTL loop tag, if it's not, throw exception
        JspException e =
            new JspException(messages.getMessage("indexed.noEnclosingIterate"));

        TagUtils.getInstance().saveException(pageContext, e);
        throw e;
    }

    /**
     * Prepares the style attributes for inclusion in the component's HTML
     * tag.
     *
     * @return The prepared String for inclusion in the HTML tag.
     * @throws JspException if invalid attributes are specified
     */
    protected String prepareStyles()
        throws JspException {
        StringBuffer styles = new StringBuffer();

        boolean errorsExist = doErrorsExist();

        if (errorsExist && (getErrorStyleId() != null)) {
            prepareAttribute(styles, "id", getErrorStyleId());
        } else {
            prepareAttribute(styles, "id", getStyleId());
        }

        if (errorsExist && (getErrorStyle() != null)) {
            prepareAttribute(styles, "style", getErrorStyle());
        } else {
            prepareAttribute(styles, "style", getStyle());
        }

        if (errorsExist && (getErrorStyleClass() != null)) {
            prepareAttribute(styles, "class", getErrorStyleClass());
        } else {
            prepareAttribute(styles, "class", getStyleClass());
        }

        prepareAttribute(styles, "title", message(getTitle(), getTitleKey()));
        prepareAttribute(styles, "alt", message(getAlt(), getAltKey()));
        prepareInternationalization(styles);

        return styles.toString();
    }

    /**
     * Determine if there are errors for the component.
     *
     * @return Whether errors exist.
     */
    protected boolean doErrorsExist()
        throws JspException {
        boolean errorsExist = false;

        if ((getErrorStyleId() != null) || (getErrorStyle() != null)
            || (getErrorStyleClass() != null)) {
            String actualName = prepareName();

            if (actualName != null) {
                ActionMessages errors =
                    TagUtils.getInstance().getActionMessages(pageContext,
                        errorKey);

                errorsExist = ((errors != null)
                    && (errors.size(actualName) > 0));
            }
        }

        return errorsExist;
    }

    /**
     * Prepares the actual name of the component.
     *
     * @return The actual component name.
     */
    protected String prepareName()
        throws JspException {
        return null;
    }
    
    /**
     * Prepares the event handlers for inclusion in the component's HTML tag.
     *
     * @return The prepared String for inclusion in the HTML tag.
     */
    protected String prepareEventHandlers() {
        StringBuffer handlers = new StringBuffer();

        prepareMouseEvents(handlers);
        prepareKeyEvents(handlers);
        prepareTextEvents(handlers);
        prepareFocusEvents(handlers);

        return handlers.toString();
    }

    /**
     * Prepares the mouse event handlers, appending them to the the given
     * StringBuffer.
     *
     * @param handlers The StringBuffer that output will be appended to.
     */
    protected void prepareMouseEvents(StringBuffer handlers) {
        prepareAttribute(handlers, "onclick", getOnclick());
        prepareAttribute(handlers, "ondblclick", getOndblclick());
        prepareAttribute(handlers, "onmouseover", getOnmouseover());
        prepareAttribute(handlers, "onmouseout", getOnmouseout());
        prepareAttribute(handlers, "onmousemove", getOnmousemove());
        prepareAttribute(handlers, "onmousedown", getOnmousedown());
        prepareAttribute(handlers, "onmouseup", getOnmouseup());
    }

    /**
     * Prepares the keyboard event handlers, appending them to the the given
     * StringBuffer.
     *
     * @param handlers The StringBuffer that output will be appended to.
     */
    protected void prepareKeyEvents(StringBuffer handlers) {
        prepareAttribute(handlers, "onkeydown", getOnkeydown());
        prepareAttribute(handlers, "onkeyup", getOnkeyup());
        prepareAttribute(handlers, "onkeypress", getOnkeypress());
    }

    /**
     * Prepares the text event handlers, appending them to the the given
     * StringBuffer.
     *
     * @param handlers The StringBuffer that output will be appended to.
     */
    protected void prepareTextEvents(StringBuffer handlers) {
        prepareAttribute(handlers, "onselect", getOnselect());
        prepareAttribute(handlers, "onchange", getOnchange());
    }

    /**
     * Prepares the focus event handlers, appending them to the the given
     * StringBuffer.
     *
     * @param handlers The StringBuffer that output will be appended to.
     */
    protected void prepareFocusEvents(StringBuffer handlers) {
        prepareAttribute(handlers, "onblur", getOnblur());
        prepareAttribute(handlers, "onfocus", getOnfocus());

        // Get the parent FormTag (if necessary)
        FormTag formTag = null;

        if ((doDisabled && !getDisabled()) || (doReadonly && !getReadonly())) {
            formTag =
                (FormTag) pageContext.getAttribute(Constants.FORM_KEY,
                    PageContext.REQUEST_SCOPE);
        }

        // Format Disabled
        if (doDisabled) {
            boolean formDisabled =
                (formTag == null) ? false : formTag.isDisabled();

            if (formDisabled || getDisabled()) {
                handlers.append(" disabled=\"disabled\"");
            }
        }

        // Format Read Only
        if (doReadonly) {
            boolean formReadOnly =
                (formTag == null) ? false : formTag.isReadonly();

            if (formReadOnly || getReadonly()) {
                handlers.append(" readonly=\"readonly\"");
            }
        }
    }

    /**
     * Prepares the internationalization attribtes, appending them to the the given
     * StringBuffer.
     *
     * @param handlers The StringBuffer that output will be appended to.
     * @since Struts 1.3.6
     */
    protected void prepareInternationalization(StringBuffer handlers) {
        prepareAttribute(handlers, "lang", getLang());
        prepareAttribute(handlers, "dir", getDir());
    }

    /**
     * 'Hook' to enable tags to be extended and additional attributes added.
     *
     * @param handlers The StringBuffer that output will be appended to.
     */
    protected void prepareOtherAttributes(StringBuffer handlers) {
    }

    /**
     * Prepares an attribute if the value is not null, appending it to the the
     * given StringBuffer.
     *
     * @param handlers The StringBuffer that output will be appended to.
     */
    protected void prepareAttribute(StringBuffer handlers, String name,
        Object value) {
        if (value != null) {
            handlers.append(" ");
            handlers.append(name);
            handlers.append("=\"");
            handlers.append(value);
            handlers.append("\"");
        }
    }

    /**
     * Allows HTML tags to find out if they're nested within an
     * %lt;html:html&gt; tag that has xhtml set to true.
     *
     * @return true if the tag is nested within an html tag with xhtml set to
     *         true, false otherwise.
     * @since Struts 1.1
     */
    protected boolean isXhtml() {
        return TagUtils.getInstance().isXhtml(this.pageContext);
    }

    /**
     * Returns the closing brace for an input element depending on xhtml
     * status.  The tag must be nested within an %lt;html:html&gt; tag that
     * has xhtml set to true.
     *
     * @return String - &gt; if xhtml is false, /&gt; if xhtml is true
     * @since Struts 1.1
     */
    protected String getElementClose() {
        return this.isXhtml() ? " />" : ">";
    }

    /**
     * Searches all scopes for the bean and calls BeanUtils.getProperty() with
     * the given arguments and converts any exceptions into JspException.
     *
     * @param beanName The name of the object to get the property from.
     * @param property The name of the property to get.
     * @return The value of the property.
     * @throws JspException
     * @since Struts 1.1
     */
    protected String lookupProperty(String beanName, String property)
        throws JspException {
        Object bean =
            TagUtils.getInstance().lookup(this.pageContext, beanName, null);

        if (bean == null) {
            throw new JspException(messages.getMessage("getter.bean", beanName));
        }

        try {
            return BeanUtils.getProperty(bean, property);
        } catch (IllegalAccessException e) {
            throw new JspException(messages.getMessage("getter.access",
                    property, beanName));
        } catch (InvocationTargetException e) {
            Throwable t = e.getTargetException();

            throw new JspException(messages.getMessage("getter.result",
                    property, t.toString()));
        } catch (NoSuchMethodException e) {
            throw new JspException(messages.getMessage("getter.method",
                    property, beanName));
        }
    }
}