src/main/java/org/apache/sling/models/annotations/injectorspecific/SlingObject.java

/*
 * 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.sling.models.annotations.injectorspecific;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import org.apache.sling.models.annotations.Source;
import org.apache.sling.models.spi.injectorspecific.InjectAnnotation;

/**
 * Injects common Sling objects that can be derived from either a SlingHttpServletRequest, a ResourceResolver or a
 * Resource.
 * <p>The injection is class-based.</p>
 * <table>
 * <caption>Supports the following objects:</caption>
 * <tr>
 * <th style="text-align:left">Class</th>
 * <th style="text-align:left">Description</th>
 * <th style="text-align:center">Request</th>
 * <th style="text-align:center">ResourceResolver</th>
 * <th style="text-align:center">Resource</th>
 * </tr>
 * <tr style="background-color:#eee">
 * <td>ResourceResolver</td>
 * <td>Resource resolver</td>
 * <td style="text-align:center">X</td>
 * <td style="text-align:center">X</td>
 * <td style="text-align:center">X</td>
 * </tr>
 * <tr>
 * <td>Resource</td>
 * <td>Resource</td>
 * <td style="text-align:center">X</td>
 * <td></td>
 * <td style="text-align:center">X</td>
 * </tr>
 * <tr style="background-color:#eee">
 * <td>SlingHttpServletRequest</td>
 * <td>Sling request</td>
 * <td style="text-align:center">X</td>
 * <td></td>
 * <td></td>
 * </tr>
 * <tr>
 * <td>SlingHttpServletResponse</td>
 * <td>Sling response</td>
 * <td style="text-align:center">X</td>
 * <td></td>
 * <td></td>
 * </tr>
 * <tr style="background-color:#eee">
 * <td>SlingScriptHelper</td>
 * <td>Sling script helper</td>
 * <td style="text-align:center">X</td>
 * <td></td>
 * <td></td>
 * </tr>
 * </table>
 */
@Target({ METHOD, FIELD, PARAMETER })
@Retention(RUNTIME)
@InjectAnnotation
@Source("sling-object")
public @interface SlingObject {

    /**
     * If set to true, the model can be instantiated even if there is no request attribute
     * with the given name found.
     * Default = false.
     * @return Optional
     * @deprecated Use {@link #injectionStrategy} instead
     */
    @Deprecated
    boolean optional() default false;

    /**
     * Specifies the injection strategy applied to an annotated element:
     * <ul>
     * <li>If set to {@link InjectionStrategy#REQUIRED}, injection is mandatory.</li>
     * <li>If set to {@link InjectionStrategy#OPTIONAL}, injection is optional.</li>
     * <li>If set to {@link InjectionStrategy#DEFAULT} (default), the default injection strategy defined on the
     * {@link org.apache.sling.models.annotations.Model} applies.</li>
     * </ul>
     * WARNING: Injection strategy is ignored if either {@link org.apache.sling.models.annotations.Optional}
     * or {@link org.apache.sling.models.annotations.Required} is applied on the same element.
     * @return Injection strategy
     */
    public InjectionStrategy injectionStrategy() default InjectionStrategy.DEFAULT;

}