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.resource; import java.util.Locale; import java.util.Map; import org.apache.wicket.Application; import org.apache.wicket.model.IModel; import org.apache.wicket.request.resource.IResource; import org.apache.wicket.request.resource.ResourceReference; import org.apache.wicket.request.resource.ResourceReferenceRegistry; import org.apache.wicket.request.resource.ResourceStreamResource; import org.apache.wicket.util.io.IClusterable; import org.apache.wicket.util.resource.IResourceStream; import org.apache.wicket.util.resource.StringResourceStream; import org.apache.wicket.util.template.PackageTextTemplate; import org.apache.wicket.util.template.TextTemplate; import org.apache.wicket.util.time.Duration; import org.apache.wicket.util.time.Time; /** * A class which adapts a {@link PackageTextTemplate} to a {@link ResourceReference}. * * @see {@link "https://cwiki.apache.org/WICKET/dynamically-generate-a-css-stylesheet.html"} * * @author James Carman */ public class TextTemplateResourceReference extends ResourceReference implements IClusterable { private static final long serialVersionUID = 1L; private final TextTemplate textTemplate; private final IModel<Map<String, Object>> variablesModel; private final ResourceStreamResource resource; /** * Creates a resource reference to a {@link PackageTextTemplate}. * * @param scope * the <code>Class</code> to be used for retrieving the classloader for loading the * <code>PackagedTextTemplate</code> * @param fileName * the file name * @param variablesModel * the template variables as a model */ public TextTemplateResourceReference(final Class<?> scope, final String fileName, IModel<Map<String, Object>> variablesModel) { this(scope, fileName, PackageTextTemplate.DEFAULT_CONTENT_TYPE, PackageTextTemplate.DEFAULT_ENCODING, variablesModel); } /** * Creates a resource reference to a {@link PackageTextTemplate}. * * @param scope * the <code>Class</code> to be used for retrieving the classloader for loading the * <code>PackagedTextTemplate</code> * @param fileName * the file name * @param contentType * the mime type of this resource, such as "<code>image/jpeg</code>" or " * <code>text/html</code>" * @param variablesModel * the template variables as a model */ public TextTemplateResourceReference(final Class<?> scope, final String fileName, final String contentType, IModel<Map<String, Object>> variablesModel) { this(scope, fileName, contentType, PackageTextTemplate.DEFAULT_ENCODING, variablesModel); } /** * Creates a resource reference to a {@link PackageTextTemplate}. * * @param scope * the <code>Class</code> to be used for retrieving the classloader for loading the * <code>PackagedTextTemplate</code> * @param fileName * the file name * @param contentType * the mime type of this resource, such as "<code>image/jpeg</code>" or " * <code>text/html</code>" * @param encoding * the file's encoding, for example, "<code>UTF-8</code>" * @param variablesModel * the template variables as a model */ public TextTemplateResourceReference(final Class<?> scope, final String fileName, final String contentType, final String encoding, IModel<Map<String, Object>> variablesModel) { this(scope, fileName, contentType, encoding, variablesModel, null, null, null); } /** * Construct. * * @param scope * the <code>Class</code> to be used for retrieving the classloader for loading the * <code>PackagedTextTemplate</code> * @param fileName * the file name * @param contentType * the mime type of this resource, such as "<code>image/jpeg</code>" or " * <code>text/html</code>" * @param encoding * the file's encoding, for example, "<code>UTF-8</code>" * @param variablesModel * the template variables as a model * @param locale * Preferred locale for the resource * @param style * Preferred style for the resource * @param variation * Preferred variation for the resource */ public TextTemplateResourceReference(final Class<?> scope, final String fileName, final String contentType, final String encoding, IModel<Map<String, Object>> variablesModel, Locale locale, String style, String variation) { super(scope, fileName, locale, style, variation); textTemplate = new PackageTextTemplate(scope, fileName, contentType, encoding); this.variablesModel = variablesModel; resource = new ResourceStreamResource(null) { @Override protected IResourceStream getResourceStream(Attributes attributes) { IModel<Map<String, Object>> variables = TextTemplateResourceReference.this.variablesModel; String stringValue = textTemplate.asString(variables.getObject()); variables.detach(); // We're done with the model so detach it! StringResourceStream resourceStream = new StringResourceStream(stringValue, textTemplate.getContentType()); resourceStream.setLastModified(Time.now()); return resourceStream; } }; resource.setCacheDuration(Duration.NONE); if (Application.exists()) { // TextTemplateResourceReference should not be cached due to its dynamic nature // Old entry in the registry would keep wrong 'variablesModel' ResourceReferenceRegistry resourceReferenceRegistry = Application.get().getResourceReferenceRegistry(); resourceReferenceRegistry.unregisterResourceReference(getKey()); resourceReferenceRegistry.registerResourceReference(this); } } /** * Creates a new resource which returns the interpolated value of the text template. * * @return a new resource which returns the interpolated value of the text template */ @Override public IResource getResource() { return resource; } }