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.request.resource; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import java.util.Locale; import org.apache.wicket.Application; import org.apache.wicket.core.util.lang.WicketObjects; import org.apache.wicket.markup.head.HeaderItem; import org.apache.wicket.util.io.IClusterable; import org.apache.wicket.util.lang.Args; import org.apache.wicket.util.lang.Objects; import org.danekja.java.util.function.serializable.SerializableSupplier; /** * Reference to a resource. Can be used to reference global resources. * <p> * Even though resource reference is just a factory for resources, it still needs to be identified * by a globally unique identifier, combination of <code>scope</code> and <code>name</code>. Those * are used to generate URLs for resource references. <code>locale</code>, <code>style</code> and * <code>variation</code> are optional fields to allow having specific references for individual * locales, styles and variations. * * @author Matej Knopp * @author Juergen Donnerstag */ public abstract class ResourceReference implements IClusterable { private static final long serialVersionUID = 1L; private final Key data; /** * Creates new {@link ResourceReference} instance. * * @param key * The data making up the resource reference */ public ResourceReference(final Key key) { Args.notNull(key, "key"); data = key; } /** * Creates new {@link ResourceReference} instance. * * @param scope * mandatory parameter * @param name * mandatory parameter * @param locale * resource locale * @param style * resource style * @param variation * resource variation */ public ResourceReference(Class<?> scope, String name, Locale locale, String style, String variation) { Args.notNull(scope, "scope"); Args.notNull(name, "name"); data = new Key(scope.getName(), name, locale, style, variation); } /** * Creates new {@link ResourceReference} instance. * * @param scope * mandatory parameter * @param name * mandatory parameter */ public ResourceReference(Class<?> scope, String name) { this(scope, name, null, null, null); } /** * Construct. * * @param name * resource name */ public ResourceReference(String name) { this(Application.class, name, null, null, null); } /** * @return Gets the data making up the resource reference. They'll be use by * ResourceReferenceRegistry to make up the key under which the resource reference gets * stored. */ public final Key getKey() { return data; } /** * @return name */ public String getName() { return data.getName(); } /** * returns extension of the resource reference * * @return extension of the resource's name in lower-case or <code>null</code> if there is no * extension */ public final String getExtension() { String name = getName(); final int queryAt = name.indexOf('?'); // remove query string part if (queryAt != -1) { name = name.substring(0, queryAt); } // get start of extension final int extPos = name.lastIndexOf('.'); if (extPos == -1) { return null; } // return extension return name.substring(extPos + 1).toLowerCase(Locale.ROOT); } /** * @return scope */ public Class<?> getScope() { return WicketObjects.resolveClass(data.getScope()); } /** * @return locale */ public Locale getLocale() { return data.getLocale(); } /** * @return style */ public String getStyle() { return data.getStyle(); } /** * @return variation */ public String getVariation() { return data.getVariation(); } /** * Can be used to disable registering certain resource references in * {@link ResourceReferenceRegistry}. * * @return <code>true</code> if this reference can be registered, <code>false</code> otherwise. */ public boolean canBeRegistered() { return true; } /** * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj instanceof ResourceReference == false) { return false; } ResourceReference that = (ResourceReference) obj; return Objects.equal(data, that.data); } /** * @see java.lang.Object#hashCode() */ @Override public int hashCode() { return data.hashCode(); } /** * Returns the resource. * * @return resource instance */ public abstract IResource getResource(); /** * Allows to specify which locale, style and variation values will the generated URL for this * resource reference have. * * @return url attributes */ public UrlAttributes getUrlAttributes() { return new UrlAttributes(getLocale(), getStyle(), getVariation()); } /** * Factory method to build a resource reference that uses the provided supplier to return * the resource. * * @param name * The name to use with the resource * @param resourceSupplier * Lambda supplier to build the resource * @return the new resource reference */ public static final ResourceReference of(String name, SerializableSupplier<IResource> resourceSupplier) { return new LambdaResourceReference(name, resourceSupplier); } /** * Factory method to build a resource reference that uses the provided supplier to return * the resource. * * @param key * The {@link Key} to use with the resource * @param resourceSupplier * Lambda supplier to build the resource * @return the new resource reference */ public static final ResourceReference of(Key key, SerializableSupplier<IResource> resourceSupplier) { return new LambdaResourceReference(key, resourceSupplier); } public static final class LambdaResourceReference extends ResourceReference { private static final long serialVersionUID = 1826862147241009289L; final SerializableSupplier<IResource> resourceBuilder; public LambdaResourceReference(String name, SerializableSupplier<IResource> resourceBuilder) { super(name); this.resourceBuilder = Args.notNull(resourceBuilder, "resourceBuilder"); } public LambdaResourceReference(Key key, SerializableSupplier<IResource> resourceBuilder) { super(key); this.resourceBuilder = Args.notNull(resourceBuilder, "resourceBuilder"); } @Override public IResource getResource() { return resourceBuilder.get(); } } /** * @see ResourceReference#getUrlAttributes() * * @author Matej Knopp */ public static class UrlAttributes { private final Locale locale; private final String style; private final String variation; /** * Construct. * * @param locale * resource locale * @param style * resource style * @param variation * resource variation */ public UrlAttributes(Locale locale, String style, String variation) { this.locale = locale; this.style = style; this.variation = variation; } /** * @return locale */ public Locale getLocale() { return locale; } /** * @return style */ public String getStyle() { return style; } /** * @return variation */ public String getVariation() { return variation; } /** * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj instanceof UrlAttributes == false) { return false; } UrlAttributes that = (UrlAttributes) obj; return Objects.equal(getLocale(), that.getLocale()) && Objects.equal(getStyle(), that.getStyle()) && Objects.equal(getVariation(), that.getVariation()); } /** * @see java.lang.Object#hashCode() */ @Override public int hashCode() { return Objects.hashCode(getLocale(), getStyle(), getVariation()); } /** * @see java.lang.Object#toString() */ @Override public String toString() { return "locale: " + locale + "; style: " + style + "; variation: " + variation; } } /** * A (re-usable) data store for all relevant ResourceReference data */ public static class Key implements Serializable { private static final long serialVersionUID = 1L; private final String scope; private final String name; private final Locale locale; private final String style; private final String variation; /** * Construct. * * @param reference * resource reference */ public Key(final ResourceReference reference) { this(reference.getScope().getName(), reference.getName(), reference.getLocale(), reference.getStyle(), reference.getVariation()); } /** * Construct. * * @param scope * resource scope * @param name * resource name * @param locale * resource locale * @param style * resource style * @param variation * resource variation */ public Key(final String scope, final String name, final Locale locale, final String style, final String variation) { Args.notNull(scope, "scope"); Args.notNull(name, "name"); this.scope = scope.intern(); this.name = name.intern(); this.locale = locale; this.style = style != null ? style.intern() : null; this.variation = variation != null ? variation.intern() : null; } /** * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(final Object obj) { if (this == obj) { return true; } if (obj instanceof Key == false) { return false; } Key that = (Key) obj; return Objects.equal(scope, that.scope) && // Objects.equal(name, that.name) && // Objects.equal(locale, that.locale) && // Objects.equal(style, that.style) && // Objects.equal(variation, that.variation); } /** * @see java.lang.Object#hashCode() */ @Override public int hashCode() { return Objects.hashCode(scope, name, locale, style, variation); } /** * Gets scope. * * @return scope */ public final String getScope() { return scope; } /** * @return Assuming scope ist a fully qualified class name, than get the associated class */ public final Class<?> getScopeClass() { return WicketObjects.resolveClass(scope); } /** * Gets name. * * @return name */ public final String getName() { return name; } /** * Gets locale. * * @return locale */ public final Locale getLocale() { return locale; } /** * Gets style. * * @return style */ public final String getStyle() { return style; } /** * Gets variation. * * @return variation */ public final String getVariation() { return variation; } /** * @see java.lang.Object#toString() */ @Override public String toString() { return "scope: " + scope + "; name: " + name + "; locale: " + locale + "; style: " + style + "; variation: " + variation; } } @Override public String toString() { return data.toString(); } /** * @return the resources this ResourceReference depends on. */ public List<HeaderItem> getDependencies() { return new ArrayList<>(); } }