Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * For further information about Alkacon Software, please see the * company website: http://www.alkacon.com * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package org.opencms.jsp.util; import org.opencms.file.CmsObject; import org.opencms.file.CmsResource; import org.opencms.flex.CmsFlexController; import org.opencms.i18n.CmsEncoder; import org.opencms.i18n.CmsLocaleManager; import org.opencms.i18n.CmsMessages; import org.opencms.main.CmsException; import org.opencms.main.OpenCms; import org.opencms.util.CmsHtml2TextConverter; import org.opencms.util.CmsRequestUtil; import org.opencms.util.CmsStringUtil; import org.opencms.util.CmsUUID; import java.text.DateFormat; import java.text.ParseException; import java.util.ArrayList; import java.util.Collections; import java.util.Date; import java.util.List; import java.util.Locale; import java.util.Map; import javax.servlet.ServletRequest; import javax.servlet.http.HttpServletRequest; import javax.servlet.jsp.PageContext; import org.apache.commons.beanutils.PropertyUtils; /** * Provides utility methods to be used as functions from a JSP with the EL.<p> * * @since 7.0.2 * * @see CmsJspContentAccessBean */ public final class CmsJspElFunctions { /** * Hide the public constructor.<p> */ private CmsJspElFunctions() { // NOOP } /** * Returns an OpenCms user context created from an Object.<p> * * <ul> * <li>If the input is already a {@link CmsObject}, it is casted and returned unchanged. * <li>If the input is a {@link ServletRequest}, the OpenCms user context is read from the request context. * <li>If the input is a {@link PageContext}, the OpenCms user context is read from the request of the page context. * <li>Otherwise the input is converted to a String which should be a user name, and creation of a OpenCms * user context with this name is attempted. Please note that this will only work if the user name is * either the "Guest" user or the "Export" user. * <li>If no valid OpenCms user context could be created with all of the above, then a new user context for * the "Guest" user is created. * </ul> * * @param input the input to create an OpenCms user context from * * @return an OpenCms user context created from an Object */ public static CmsObject convertCmsObject(Object input) { CmsObject result; if (input instanceof CmsObject) { result = (CmsObject) input; } else if (input instanceof ServletRequest) { result = CmsFlexController.getCmsObject((ServletRequest) input); } else if (input instanceof PageContext) { result = CmsFlexController.getCmsObject(((PageContext) input).getRequest()); } else { try { // try to use the given name as user name result = OpenCms.initCmsObject(String.valueOf(input)); // try to set the right site root ServletRequest req = convertRequest(input); if (req instanceof HttpServletRequest) { result.getRequestContext().setSiteRoot( OpenCms.getSiteManager().matchRequest((HttpServletRequest) req).getSiteRoot()); } } catch (CmsException e) { result = null; } } if (result == null) { try { result = OpenCms.initCmsObject(OpenCms.getDefaultUsers().getUserGuest()); // try to set the right site root ServletRequest req = convertRequest(input); if (req instanceof HttpServletRequest) { result.getRequestContext().setSiteRoot( OpenCms.getSiteManager().matchRequest((HttpServletRequest) req).getSiteRoot()); } } catch (CmsException e1) { // this should never fail since we can always create a "Guest" user } } return result; } /** * Returns a Date created from an Object.<p> * * <ul> * <li>The Object is first checked if it is a {@link Date} already, if so it is casted and returned unchanged. * <li>If not, the input is checked if it is a {@link Long}, and if so the Date is created from the Long value. * <li>If it's not a Date and not a Long, the Object is transformed to a String and then it's tried * to parse a Long out of the String. * <li>If this fails, it is tried to parse as a Date using the * default date formatting. * <li>If this also fails, a new Date is returned that has been initialized with 0.<p> * </ul> * * @param input the Object to create a Date from * * @return a Date created from the given Object */ public static Date convertDate(Object input) { Date result; if (input instanceof Date) { result = (Date) input; } else if (input instanceof Long) { result = new Date(((Long) input).longValue()); } else { String str = String.valueOf(input); try { // treat the input as a String long l = Long.parseLong(str); result = new Date(l); } catch (NumberFormatException e) { try { // try to parse String as a Date result = DateFormat.getDateInstance().parse(str); } catch (ParseException e1) { result = null; } if (result == null) { // use default date if parsing fails result = new Date(0); } } } return result; } /** * Returns a list of attribute values specified by the attribute name of the items of the given list.<p> * * @param input the list of objects to obtain the attribute values from * @param attributeName the name of the attribute to obtain * @return a list of attributes specified by the attribute name of the items of the given list */ public static List<Object> convertList(List<Object> input, String attributeName) { List<Object> result = new ArrayList<Object>(input.size()); for (Object item : input) { try { result.add(PropertyUtils.getProperty(item, attributeName)); } catch (Exception e) { // specified attribute is not implemented, return empty list return Collections.emptyList(); } } return result; } /** * Returns a Locale created from an Object.<p> * * <ul> * <li>The Object is first checked if it is a {@link Locale} already, if so it is casted and returned. * <li>If not, the input is transformed to a String and then a Locale lookup with this String is done. * <li>If the locale lookup fails, the OpenCms default locale is returned. * </ul> * * @param input the Object to create a Locale from * * @return a Locale created from the given Object */ public static Locale convertLocale(Object input) { Locale locale; if (input instanceof Locale) { locale = (Locale) input; } else { locale = CmsLocaleManager.getLocale(String.valueOf(input)); } return locale; } /** * Tries to convert the given input object into a request.<p> * * This is only possible if the input object is already a request * or if it is a page context.<p> * * If everything else, this method returns <code>null</code>.<p> * * @param input the input object to convert to a request * * @return a request object, or <code>null</code> */ public static ServletRequest convertRequest(Object input) { ServletRequest req = null; if (input instanceof ServletRequest) { req = (ServletRequest) input; } else if (input instanceof PageContext) { req = ((PageContext) input).getRequest(); } return req; } /** * Returns a resource created from an Object.<p> * * <ul> * <li>If the input is already a {@link CmsResource}, it is casted to the resource and returned unchanged. * <li>If the input is a String, the given OpenCms context is used to read a resource with this name from the VFS. * <li>If the input is a {@link CmsUUID}, the given OpenCms context is used to read a resource with * this UUID from the VFS. * <li>Otherwise the input is converted to a String, and then the given OpenCms context is used to read * a resource with this name from the VFS. * </ul> * * @param cms the current OpenCms user context * @param input the input to create a resource from * * @return a resource created from the given Object * * @throws CmsException in case of errors accessing the OpenCms VFS for reading the resource */ public static CmsResource convertResource(CmsObject cms, Object input) throws CmsException { CmsResource result; if (input instanceof String) { // input is a String result = cms.readResource((String) input); } else if (input instanceof CmsResource) { // input is already a resource result = (CmsResource) input; } else if (input instanceof CmsUUID) { // input is a UUID result = cms.readResource((CmsUUID) input); } else { // input seems not really to make sense, try to use it like a String result = cms.readResource(String.valueOf(input)); } return result; } /** * Returns a CmsUUID created from an Object.<p> * * <ul> * <li>The Object is first checked if it is a {@link CmsUUID} already, if so it is casted and returned. * <li>If not, the input is transformed to a byte[] and a new {@link CmsUUID} is created with this byte[]. * <li>Otherwise the input is casted to a String and a new {@link CmsUUID} is created with this String. * </ul> * * @param input the Object to create a CmsUUID from * * @return a CmsUUID created from the given Object */ public static CmsUUID convertUUID(Object input) { CmsUUID uuid; if (input instanceof CmsUUID) { uuid = (CmsUUID) input; } else if (input instanceof byte[]) { uuid = new CmsUUID((byte[]) input); } else { uuid = new CmsUUID(String.valueOf(input)); } return uuid; } /** * Encodes a String in a way that is compatible with the JavaScript escape function. * * @param source The text to be encoded * @param encoding the encoding type * * @return The JavaScript escaped string */ public static String escape(String source, String encoding) { return CmsEncoder.escape(source, encoding); } /** * Returns the current OpenCms user context from the given page context.<p> * * @param input the input to create a CmsObject from * * @return the current OpenCms user context from the given page context */ public static CmsObject getCmsObject(Object input) { return convertCmsObject(input); } /** * Returns the size of the given list.<p> * * @param input the list of objects to obtain the size from * @return the size of the given list */ public static Integer getListSize(List<Object> input) { if (input != null) { return Integer.valueOf(input.size()); } // input was null return Integer.valueOf(0); } /** * Returns the current navigation URI.<p> * * Which can be the request URI or the VFS resource URI.<p> * * In case a sitemap is used, the navigation URI will be the * request URI, if not the VFS resource URI is returned.<p> * * @param input the request convertible object to get the navigation URI from * * @return the current navigation URI */ public static String getNavigationUri(Object input) { ServletRequest req = convertRequest(input); if (req == null) { return null; } return getCmsObject(input).getRequestContext().getUri(); } /** * Returns the link without parameters from a String that is formatted for a GET request.<p> * * @param url the URL to remove the parameters from * @return the link without parameters */ public static String getRequestLink(String url) { return CmsRequestUtil.getRequestLink(url); } /** * Returns the value of a parameter from a String that is formatted for a GET request.<p> * * @param url the URL to get the parameter value from * @param paramName the request parameter name * @return the value of the parameter */ public static String getRequestParam(String url, String paramName) { Map<String, String[]> params = Collections.emptyMap(); if (CmsStringUtil.isNotEmpty(url)) { int pos = url.indexOf(CmsRequestUtil.URL_DELIMITER); if (pos >= 0) { params = CmsRequestUtil.createParameterMap(url.substring(pos + 1)); } } String[] result = params.get(paramName); if (result != null) { return result[0]; } return null; } /** * Returns a JSP / EL VFS access bean.<p> * * @param input the Object to create a CmsObject from * * @return a JSP / EL VFS access bean */ public static CmsJspVfsAccessBean getVfsAccessBean(Object input) { return CmsJspVfsAccessBean.create(CmsJspElFunctions.convertCmsObject(input)); } /** * Strips all HTML markup from the given input.<p> * * <ul> * <li>In case the input is an instance of {@link CmsJspContentAccessValueWrapper}, an optimized * method is used for the HTML stripping. * <li>Otherwise the input is converted to a String and this String is stripped. * </ul> * * @param input the input to Strip from HTML * * @return the given input with all HTML stripped. */ public static String stripHtml(Object input) { if (input instanceof CmsJspContentAccessValueWrapper) { CmsJspContentAccessValueWrapper wrapper = (CmsJspContentAccessValueWrapper) input; if (wrapper.getExists()) { return wrapper.obtainContentValue().getPlainText(wrapper.obtainCmsObject()); } else { return ""; } } try { return CmsHtml2TextConverter.html2text(String.valueOf(input), OpenCms.getSystemInfo().getDefaultEncoding()); } catch (Exception e) { return CmsMessages.formatUnknownKey(e.getMessage()); } } /** * Returns a substring of the source, which is at most length characters long.<p> * * If a char is cut, <code>" ..."</code> is appended to the result.<p> * * @param input the string to trim * @param length the maximum length of the string to be returned * * @return a substring of the source, which is at most length characters long * * @see CmsStringUtil#trimToSize(String, int, String) */ public static String trimToSize(String input, int length) { return CmsStringUtil.trimToSize(input, length, " ..."); } /** * Decodes a String in a way that is compatible with the JavaScript * unescape function.<p> * * @param source The String to be decoded * @param encoding the encoding type * * @return The JavaScript unescaped String */ public static String unescape(String source, String encoding) { return CmsEncoder.unescape(source, encoding); } }