Java tutorial
/** * Copyright 2012 Vineet Semwal Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package com.aplombee; import org.apache.wicket.*; import org.apache.wicket.ajax.AjaxRequestTarget; import org.apache.wicket.markup.head.IHeaderResponse; import org.apache.wicket.markup.head.JavaScriptHeaderItem; import org.apache.wicket.markup.repeater.IItemFactory; import org.apache.wicket.markup.repeater.Item; import org.apache.wicket.markup.repeater.RepeatingView; import org.apache.wicket.markup.repeater.data.IDataProvider; import org.apache.wicket.model.IModel; import org.apache.wicket.request.cycle.RequestCycle; import org.apache.wicket.util.lang.Args; import org.apache.wicket.util.visit.IVisit; import org.apache.wicket.util.visit.IVisitor; import java.util.*; /** * base class for {@link QuickView} * * @author Vineet Semwal */ public abstract class QuickViewBase<T> extends RepeatingView implements IQuickView { private IQuickReuseStrategy reuseStrategy; public void setReuseStrategy(IQuickReuseStrategy reuseStrategy) { Args.notNull(reuseStrategy, "reuseStrategy"); this.reuseStrategy = reuseStrategy; } public IQuickReuseStrategy getReuseStrategy() { return reuseStrategy; } //items created per request ,if used with PagingNavigator/AjaxPagingNavigator then it's the items per page private long itemsPerRequest = Integer.MAX_VALUE; public long getItemsPerRequest() { return itemsPerRequest; } private long childId = 0; @Override public String newChildId() { childId++; return String.valueOf(childId); } public void setItemsPerRequest(long items) { if (items < 1) { throw new IllegalArgumentException("itemsPerRequest cannot be less than 1"); } if (this.itemsPerRequest != items) { if (isVersioned()) { addStateChange(); } this.itemsPerRequest = items; // because items per page can effect the total number of pages we always // reset the current page back to zero _setCurrentPage(0); } } private transient long itemsCount = -1; private IDataProvider<T> dataProvider; public IDataProvider<T> getDataProvider() { return dataProvider; } protected IRepeaterUtil getRepeaterUtil() { return RepeaterUtil.get(); } private long currentPage; /** * @param id component id * @param dataProvider dataprovider of objects * @param reuse children are created again on render * */ public QuickViewBase(String id, IDataProvider<T> dataProvider, IQuickReuseStrategy reuseStrategy) { super(id); Args.notNull(dataProvider, "dataProvider"); Args.notNull(reuseStrategy, "reuseStrategy"); this.dataProvider = dataProvider; this.reuseStrategy = reuseStrategy; } protected Item<T> newItem(String id, long index, IModel<T> model) { Item<T> item = new Item<T>(id, getRepeaterUtil().safeLongToInt(index), model); item.setOutputMarkupId(true); return item; } /** * use in stateless environment as there is no state ,it's user's responsiblity to give unique id and index * * @param id * @param index * @param object * @return */ public Item<T> buildItem(String id, long index, T object) { return buildItem(id, index, getDataProvider().model(object)); } protected Item<T> buildItem(String id, long index, IModel<T> model) { Item<T> item = newItem(id, index, model); populate(item); return item; } /** * * creates new item,for stateless environment,you can use {@link QuickViewBase#buildItem} or {@link QuickViewBase#buildItem} * * @param object model object * @return item */ public Item buildItem(long index, T object) { return buildItem(newChildId(), index, object); } protected Item buildItem(long index, IModel<T> model) { return buildItem(newChildId(), index, model); } public boolean isAjax() { return getWebRequest().isAjax(); } /** * it's a simple add,new item is not drawn just added,no js fired * @param c component to be added * @return this */ public MarkupContainer simpleAdd(Component... c) { super.add(c); return this; } /** * it's a simple remove,the item is just removed from quickview ,no js fired * @param c * @return this */ public MarkupContainer simpleRemove(Component c) { super.remove(c); return this; } public MarkupContainer simpleRemoveAll() { return super.removeAll(); } public Iterator<Component> itemsIterator() { return iterator(); } @Override protected void onPopulate() { super.onPopulate(); clearCachedItemCount(); // if reuse strategy creates items for zero page every time QuickView is re-rendered if (reuseStrategy.isAlwaysZeroPageCreatedOnRender()) { _setCurrentPage(0); } long page = _getCurrentPage(); Iterator<Item<T>> existing = (Iterator) itemsIterator(); long offset = page * getItemsPerRequest(); Iterator<IModel<T>> newModels = newModels(offset, itemsPerRequest); Iterator<Item<T>> newIterator = reuseStrategy.getItems(factory(), newModels, existing); simpleRemoveAll(); createChildren(newIterator); } public IItemFactory<T> factory() { return new IItemFactory<T>() { @Override public Item<T> newItem(int index, IModel<T> model) { return buildItem(index, model); } }; } @Override public List<Item<T>> addItemsForPage(final long page) { long offset = page * getItemsPerRequest(); Iterator<IModel<T>> newModels = newModels(offset, itemsPerRequest); Iterator<Item<T>> newIterator = reuseStrategy.addItems(getRepeaterUtil().safeLongToInt(offset), factory(), newModels); List<Item<T>> components = new ArrayList<Item<T>>(); while (newIterator.hasNext()) { Item<T> temp = newIterator.next(); components.add(temp); add(temp); } return components; } /** * Helper class that converts input from IDataProvider to an iterator over view items. * * @author Igor Vaynberg (ivaynberg) * * @param <T> * Model object type */ protected static final class ModelIterator<T> implements Iterator<IModel<T>> { private final Iterator<? extends T> items; private final IDataProvider<T> dataProvider; private final long max; private long index; /** * Constructor * * @param dataProvider * data provider * @param offset * index of first item * @param count * max number of items to return */ public ModelIterator(IDataProvider<T> dataProvider, long offset, long count) { this.dataProvider = dataProvider; max = count; items = count > 0 ? dataProvider.iterator(offset, count) : null; } /** * @see java.util.Iterator#remove() */ @Override public void remove() { throw new UnsupportedOperationException(); } /** * @see java.util.Iterator#hasNext() */ @Override public boolean hasNext() { return items != null && items.hasNext() && (index < max); } /** * @see java.util.Iterator#next() */ @Override public IModel<T> next() { index++; return dataProvider.model(items.next()); } } protected Iterator<IModel<T>> newModels(long offset, long count) { return new ModelIterator<T>(dataProvider, offset, count); } public Item<T> getItem(long index) { return (Item) get(getRepeaterUtil().safeLongToInt(index)); } protected void createChildren(Iterator<Item<T>> iterator) { Args.notNull(iterator, "iterator"); while (iterator.hasNext()) { Item<T> item = iterator.next(); simpleAdd(item); } } protected Iterator<Item<T>> buildItems(final long index, Iterator<? extends T> iterator) { List<Item<T>> items = new ArrayList<Item<T>>(); for (long i = index; iterator.hasNext(); i++) { T object = iterator.next(); Item<T> item = buildItem(i, object); items.add(item); } return items.iterator(); } /* * build items from index=size */ protected Iterator<Item<T>> buildItems(Iterator<? extends T> iterator) { long index = size(); return buildItems(index, iterator); } @Override public void renderHead(IHeaderResponse response) { super.renderHead(response); response.render(JavaScriptHeaderItem.forReference(RepeaterUtilReference.get())); /** * jquery reference added,it's not important as wicket itself uses jquery in ajax use case but still added to be safe */ response.render(JavaScriptHeaderItem .forReference(Application.get().getJavaScriptLibrarySettings().getJQueryReference())); } public final long getItemsCount() { if (itemsCount >= 0) { return itemsCount; } itemsCount = getDataProvider().size(); return itemsCount; } private void clearCachedItemCount() { itemsCount = -1; } public long getRowsCount() { if (!isVisibleInHierarchy()) { return 0; } return getItemsCount(); } /** * calculates the number of pages * * * @return number of pages */ @Override public final long getPageCount() { return _getPageCount(); } /** * don't override ,it's used for testing purpose * * @return number of pages */ protected long _getPageCount() { long total = getRowsCount(); long count = total / itemsPerRequest; if ((itemsPerRequest * count) < total) { count++; } return count; } /** * @see org.apache.wicket.markup.html.navigation.paging.IPageable#getCurrentPage() * * don't override */ @Override public final long getCurrentPage() { return _getCurrentPage(); } /** * don't override,it's for internal use * */ protected long _getCurrentPage() { long page = currentPage; /* * trim current page if its out of bounds this can happen if items are added/deleted between * requests */ final long count = _getPageCount(); if (page > 0 && page >= count) { page = Math.max(count - 1, 0); currentPage = page; return page; } return page; } /** * @see org.apache.wicket.markup.html.navigation.paging.IPageable#setCurrentPage(long) */ public final void setCurrentPage(long page) { _setCurrentPage(page); } /** * don't override,it's for internal use * */ protected void _setCurrentPage(long page) { if (currentPage != page) { if (isVersioned()) { addStateChange(); } } currentPage = page; } public AjaxRequestTarget getAjaxRequestTarget() { return RequestCycle.get().find(AjaxRequestTarget.class); } protected abstract void populate(Item<T> item); public static class ChildVisitor implements IVisitor<Component, Boolean> { private Component searchFor; public ChildVisitor(Component searchFor) { this.searchFor = searchFor; } public void component(Component c, IVisit<Boolean> visit) { if (searchFor.getPageRelativePath().equals(c.getPageRelativePath())) { visit.stop(true); } } } /** * don't override,it's for internal use * */ protected MarkupContainer _getParent() { return getParent(); } @Override public MarkupContainer add(final Component... components) { simpleAdd(components); if (!isAjax()) { return this; } for (int i = 0; i < components.length; i++) { MarkupContainer parent = _getParent(); String script = getRepeaterUtil().append((Item) components[i], parent); getSynchronizer().getPrependScripts().add(script); } getSynchronizer().add(components); return this; } /** * * * this does 2 steps * * 1)creates children ,children will get the model object after iterating over objects passed as argument * 2)adds children to View using {@link this#add(org.apache.wicket.Component...)} * @param objects iterator of model objects for children * @return this */ public MarkupContainer addNewItems(T... objects) { List<T> list = new ArrayList<T>(); for (T obj : objects) { list.add(obj); } Iterator<Item<T>> items = buildItems(list.iterator()); while (items.hasNext()) { add(items.next()); } return this; } /** * this does 2 steps * * 1)creates children ,children will get the model object after iterating over objects passed as argument * 2)adds children to View using {@link this#addAtStart(org.apache.wicket.Component...)} * @param objects iterator of model objects for children * @return this */ public MarkupContainer addNewItemsAtStart(T... objects) { List<T> list = new ArrayList<T>(); for (T obj : objects) { list.add(obj); } Iterator<Item<T>> items = buildItems(list.iterator()); while (items.hasNext()) { addAtStart(items.next()); } return this; } /** * {@inheritDoc} */ public List<Item<T>> addItemsForNextPage() { List<Item<T>> list = new ArrayList<Item<T>>(); long current = getCurrentPage(); // page for which new items have to created long next = current + 1; if (next < _getPageCount()) { list = addItemsForPage(next); _setCurrentPage(next); } return list; } @Override public MarkupContainer remove(final Component component) { Args.notNull(component, "component can't be null"); if (isAjax()) { String removeScript = getRepeaterUtil().removeItem(component, _getParent()); getSynchronizer().getPrependScripts().add(removeScript); } return simpleRemove(component); } @Override public MarkupContainer remove(final String id) { final Component component = get(id); return remove(component); } /** * draws a new element at start but actually the element is added at last in repeater, * this should not pose problem when whole repeater is rendered and if data is sorted * * @param components * @return this */ public MarkupContainer addAtStart(final Component... components) { simpleAdd(components); if (!isAjax()) { return this; } for (int i = 0; i < components.length; i++) { MarkupContainer parent = _getParent(); String updateBeforeScript = getRepeaterUtil().prepend((Item) components[i], parent); getSynchronizer().getPrependScripts().add(updateBeforeScript); } getSynchronizer().add(components); return this; } /** * when called on ajax event ,this method moves navigation-bar to bottom, * this works when parent has scroll specified in css by defining overflow-y property * */ public void scrollToBottom() { if (isAjax()) { AjaxRequestTarget target = this.getAjaxRequestTarget(); target.appendJavaScript(getRepeaterUtil().scrollToBottom(this)); } } /** * when called on ajax event, this method moves navigation-bar to top , * this works when parent has scroll specified in css by defining overflow-y property * */ public void scrollToTop() { if (isAjax()) { AjaxRequestTarget target = this.getAjaxRequestTarget(); target.appendJavaScript(getRepeaterUtil().scrollToTop(this)); } } /** * when called on ajax event, this method moves navigation-bar to height passed in method , * this works when parent has scroll specified in css by defining overflow-y property * */ public void scrollTo(int height) { if (isAjax()) { AjaxRequestTarget target = this.getAjaxRequestTarget(); target.appendJavaScript(getRepeaterUtil().scrollTo(this, height)); } } /** * * less complex/preferred/clear solution would have been checking if listener is already added in AjaxRequestTarget but * since there is no getter for IListeners,there is no way to know listener is added ,it might be added in later versions * see WICKET-4800 * * @return Synchronizer */ public Synchronizer getSynchronizer() { AjaxRequestTarget target = getAjaxRequestTarget(); if (target == null) { return null; } Synchronizer listener = (Synchronizer) getRequestCycle().getMetaData(synchronizerKey); if (listener == null) { listener = new Synchronizer(_getParent()); getRequestCycle().setMetaData(synchronizerKey, listener); target.addListener(listener); } return listener; } /** Synchronizer basically adds components(repeater's items) and scripts to the the AjaxRequestTarget after * checking parent is not added to AjaxRequestTarget .If parent is added scripts and * items are not added to the AjaxRequestTarget * * * @author Vineet Semwal */ public static class Synchronizer implements AjaxRequestTarget.IListener { private List<String> prependScripts = new ArrayList<String>(); /** * mostly contains items od repeater that will be added to AjaxRequestTarget */ private List<Component> components = new ArrayList<Component>(); public List<String> getPrependScripts() { return prependScripts; } public List<Component> getComponents() { return components; } private MarkupContainer searchFor; public Synchronizer(MarkupContainer searchFor) { Args.notNull(searchFor, "searchFor"); this.searchFor = searchFor; } @Override public void onBeforeRespond(Map<String, Component> map, AjaxRequestTarget target) { if (!isParentAddedInAjaxRequestTarget(target)) { for (String script : prependScripts) { target.prependJavaScript(script); } target.add(components.toArray(new Component[0])); } } public void add(Component... cs) { for (final Component component : cs) { Args.notNull(component, "component"); components.add(component); } } @Override public void onAfterRespond(Map<String, Component> map, AjaxRequestTarget.IJavaScriptResponse response) { } /** * checks if parent of repeater is added to the components added to * A.R.T(ajaxrequesttarget) * * @return true if parent of repeatingview is added to A.R.T */ public boolean isParentAddedInAjaxRequestTarget(AjaxRequestTarget target) { Collection<? extends Component> cs = target.getComponents(); if (cs == null) { return false; } if (cs.isEmpty()) { return false; } //if repeater's parent is added to component return true if (cs.contains(searchFor)) { return true; } //search repeater's parent in children of components added in A.R.T boolean found = false; for (Component c : cs) { if (c instanceof MarkupContainer) { MarkupContainer mc = (MarkupContainer) c; Boolean result = addNewChildVisitor(mc, searchFor); if (Boolean.TRUE.equals(result)) { found = true; break; } } } return found; } /** * @param parent parent on which ChildVisitor is added * @param searchFor ,searchFor is the component which visitor search for * @return true if searchFor is found */ protected Boolean addNewChildVisitor(MarkupContainer parent, Component searchFor) { return parent.visitChildren(new ChildVisitor(searchFor)); } } /** * key corresponding to AjaxRequestTarget.IListener in request metadata */ private MetaDataKey<AjaxRequestTarget.IListener> synchronizerKey = new MetaDataKey<AjaxRequestTarget.IListener>() { }; @Override protected void onDetach() { dataProvider.detach(); super.onDetach(); } }