Java tutorial
/* * RHQ Management Platform * Copyright (C) 2005-2008 Red Hat, Inc. * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation version 2 of the License. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ package org.rhq.enterprise.gui.common.paging; import java.beans.FeatureDescriptor; import java.util.Iterator; import javax.el.ELContext; import javax.el.ELResolver; import javax.el.PropertyNotFoundException; import javax.el.PropertyNotWritableException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.rhq.core.domain.util.PageControl; import org.rhq.enterprise.gui.legacy.WebUser; import org.rhq.enterprise.gui.legacy.WebUserPreferences; import org.rhq.enterprise.gui.util.EnterpriseFacesContextUtility; /** * @author Joseph Marques */ public class PageControlELResolver extends ELResolver { private final Log log = LogFactory.getLog(this.getClass()); @Override public Class<?> getCommonPropertyType(ELContext context, Object base) { return null; // for gui tools } @Override public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) { return null; // for gui tools } @Override public Class<?> getType(ELContext context, Object base, Object property) { Class<?> result = null; if (context == null) { throw new NullPointerException("ELContext was null for getType method in PageControlELResolver"); } if (base == null) { // We don't handle setting top-level implicit objects. } else if (base.equals(PageControlView.class) || (base instanceof PageControlView)) { String propertyName = property.toString().toLowerCase(); if ("pagesize".equals(propertyName)) { result = Integer.class; } else if ("pagenumber".equals(propertyName)) { result = Integer.class; } else if ("unlimited".equals(propertyName)) { result = Boolean.class; } else { throw new PropertyNotWritableException( "Only the pageSize and pageNumber properties of a PageControl object can be resolved"); } context.setPropertyResolved(true); } return result; } @Override public Object getValue(ELContext context, Object base, Object property) { if (context == null) { throw new NullPointerException("ELContext was null for getValue method in PageControlELResolver"); } Object result = null; if (base == null) { // Resolving first two variables (e.g. ${PageControlView.something}). String propertyName = (String) property; if ("PageControl".equals(propertyName)) { result = PageControlView.class; context.setPropertyResolved(true); } } else if (PageControlView.class.equals(base)) { // Getting a specific PageControlView instance String viewName = property.toString(); result = PageControlView.valueOf(viewName); context.setPropertyResolved(true); } else if (base instanceof PageControlView) { // cast to required types PageControlView view = (PageControlView) base; String methodName = (String) property; String lowerCaseMethodName = methodName.toLowerCase(); log.debug("accessing PageControl." + methodName); // allows simple misspellings for developer productivity if ("pagesize".equals(lowerCaseMethodName)) { // find the user for this session-based operation WebUser user = EnterpriseFacesContextUtility.getWebUser(); WebUserPreferences preferences = user.getWebPreferences(); // get it PageControl pc = preferences.getPageControl(view); if (log.isDebugEnabled()) { log.debug("Getting PageControlView[" + view + "] to " + pc); } result = pc.getPageSize(); } else if ("pagenumber".equals(lowerCaseMethodName)) { // find the user for this session-based operation WebUser user = EnterpriseFacesContextUtility.getWebUser(); WebUserPreferences preferences = user.getWebPreferences(); // get it PageControl pc = preferences.getPageControl(view); if (log.isDebugEnabled()) { log.debug("Getting PageControlView[" + view + "] to " + pc); } result = pc.getPageNumber() + 1; // RF data table is 1-based, our PageControl is 0-based } else if ("unlimited".equals(lowerCaseMethodName)) { result = view.isUnlimited(); } else { throw new PropertyNotFoundException( "The " + methodName + " property of a PageControl object is not accessible"); } // don't let other resolvers touch this context.setPropertyResolved(true); } return result; } @Override public boolean isReadOnly(ELContext context, Object base, Object property) { return false; } @Override public void setValue(ELContext context, Object base, Object property, Object value) { if (context == null) { throw new NullPointerException("ELContext was null for setValue method in PageControlELResolver"); } if (base instanceof PageControlView) { // cast to required types PageControlView view = (PageControlView) base; String methodName = (String) property; String lowerCaseMethodName = methodName.toLowerCase(); // allows simple mispellings for developer productivity if ("pagesize".equals(lowerCaseMethodName)) { if (value != null) { // find the user for this session-based operation WebUser user = EnterpriseFacesContextUtility.getWebUser(); WebUserPreferences preferences = user.getWebPreferences(); // update it PageControl pc = preferences.getPageControl(view); int pageSize = (Integer) value; if (pc.getPageSize() == pageSize) { // nothing to do if (log.isDebugEnabled()) { log.debug("PageControlView[" + view + "] needs no changes " + pc); } } else { pc.setPageSize(pageSize); pc.setPageNumber(0); // reset the page number too if (log.isDebugEnabled()) { log.debug("Setting PageControlView[" + view + "] to " + pc); } preferences.setPageControl(view, pc); } } // don't let other resolvers touch this context.setPropertyResolved(true); } else if ("pagenumber".equals(lowerCaseMethodName)) { if (value != null) { // find the user for this session-based operation WebUser user = EnterpriseFacesContextUtility.getWebUser(); WebUserPreferences preferences = user.getWebPreferences(); // update it PageControl pc = preferences.getPageControl(view); int pageNumber = (Integer) value; pc.setPageNumber(pageNumber - 1); // RF data table is 1-based, our PageControl is 0-based if (log.isDebugEnabled()) { log.debug("Setting PageControlView[" + view + "] to " + pc); } preferences.setPageControl(view, pc); } // don't let other resolvers touch this context.setPropertyResolved(true); } else { throw new PropertyNotFoundException( "The " + methodName + " property of a PageControl object can not be set, only pageSize"); } } } }