Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.wicket.settings; import java.io.File; import java.io.IOException; import org.apache.wicket.Application; import org.apache.wicket.WicketRuntimeException; import org.apache.wicket.protocol.http.WebApplication; import org.apache.wicket.util.lang.Args; import org.apache.wicket.util.lang.Bytes; /** * A class for settings related to the the storages where page instances are persisted - * {@link org.apache.wicket.pageStore.IPageStore}, * {@link org.apache.wicket.pageStore.IDataStore} and {@link org.apache.wicket.page.IPageManager}. * <p> * For more information about page storages read <a * href="https://cwiki.apache.org/confluence/x/qIaoAQ">Page Storage - Wiki page</a> * </p> * * @since 1.5 */ public class StoreSettings { /** * By default the second level cache is disabled. * * @see <a href="https://issues.apache.org/jira/browse/WICKET-5554">WICKET-5554</a> * @see <a href="https://cwiki.apache.org/confluence/x/qIaoAQ">Wicket Page storages</a> */ private static final int DEFAULT_CACHE_SIZE = 0; private static final Bytes DEFAULT_MAX_SIZE_PER_SESSION = Bytes.megabytes(10); private static final int DEFAULT_ASYNCHRONOUS_QUEUE_CAPACITY = 100; private int inmemoryCacheSize = DEFAULT_CACHE_SIZE; private Bytes maxSizePerSession = DEFAULT_MAX_SIZE_PER_SESSION; private File fileStoreFolder = null; private int asynchronousQueueCapacity = DEFAULT_ASYNCHRONOUS_QUEUE_CAPACITY; private boolean isAsynchronous = true; /** * Construct. * * @param application */ public StoreSettings(final Application application) { } /** * @return the number of page instances which will be stored in the application scoped cache for * faster retrieval */ public int getInmemoryCacheSize() { return inmemoryCacheSize; } /** * Sets the maximum number of page instances which will be stored in the application scoped * second level cache for faster retrieval * * @param inmemoryCacheSize * the maximum number of page instances which will be held in the application scoped * cache * @return {@code this} object for chaining */ public StoreSettings setInmemoryCacheSize(int inmemoryCacheSize) { this.inmemoryCacheSize = inmemoryCacheSize; return this; } /** * @return maximum page size. After this size is exceeded, * the {@link org.apache.wicket.pageStore.DiskDataStore} will start saving the * pages at the beginning of file. */ public Bytes getMaxSizePerSession() { return maxSizePerSession; } /** * Sets the maximum size of the {@link File} where page instances per session are stored. After * reaching this size the {@link org.apache.wicket.pageStore.DiskDataStore} will start overriding the * oldest pages at the beginning of the file. * * @param maxSizePerSession * the maximum size of the file where page instances are stored per session. In * bytes. * @return {@code this} object for chaining */ public StoreSettings setMaxSizePerSession(final Bytes maxSizePerSession) { this.maxSizePerSession = Args.notNull(maxSizePerSession, "maxSizePerSession"); return this; } /** * @return the location of the folder where {@link org.apache.wicket.pageStore.DiskDataStore} will store the files with page * instances per session */ public File getFileStoreFolder() { if (fileStoreFolder == null) { if (WebApplication.exists()) { fileStoreFolder = (File) WebApplication.get().getServletContext() .getAttribute("javax.servlet.context.tempdir"); } if (fileStoreFolder != null) { return fileStoreFolder; } try { fileStoreFolder = File.createTempFile("file-prefix", null).getParentFile(); } catch (IOException e) { throw new WicketRuntimeException(e); } } return fileStoreFolder; } /** * Sets the folder where {@link org.apache.wicket.pageStore.DiskDataStore} will store the files with page instances per * session * * @param fileStoreFolder * the new location * @return {@code this} object for chaining */ public StoreSettings setFileStoreFolder(final File fileStoreFolder) { this.fileStoreFolder = Args.notNull(fileStoreFolder, "fileStoreFolder"); return this; } /** * @return the capacity of the queue used to store the pages which will be stored asynchronously * @see org.apache.wicket.pageStore.AsynchronousDataStore */ public int getAsynchronousQueueCapacity() { return asynchronousQueueCapacity; } /** * Sets the capacity of the queue used to store the pages which will be stored asynchronously * * @param queueCapacity * the capacity of the queue * @see org.apache.wicket.pageStore.AsynchronousDataStore * @return {@code this} object for chaining */ public StoreSettings setAsynchronousQueueCapacity(int queueCapacity) { if (queueCapacity < 1) { throw new IllegalArgumentException("The capacity of the asynchronous queue should be at least 1."); } asynchronousQueueCapacity = queueCapacity; return this; } /** * Sets a flag whether to wrap the configured {@link org.apache.wicket.pageStore.IDataStore} with * {@link org.apache.wicket.pageStore.AsynchronousDataStore}. By doing this the HTTP worker thread will not wait for the * actual write of the page's bytes into the wrapped {@link org.apache.wicket.pageStore.IDataStore}. * * @param async * {@code true} to make it asynchronous, {@code false} - otherwise * @return {@code this} object for chaining */ public StoreSettings setAsynchronous(boolean async) { isAsynchronous = async; return this; } /** * @return {@code true} if the storing of page's bytes is asynchronous */ public boolean isAsynchronous() { return isAsynchronous; } }