| /* |
| * ==================================================================== |
| * 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| */ |
| |
| package org.apache.hc.core5.http; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import java.util.List; |
| |
| import org.apache.hc.core5.function.Supplier; |
| |
| /** |
| * An entity that can be sent or received with an HTTP message. |
| * <p> |
| * There are three distinct types of entities in HttpCore, |
| * depending on where their {@link #getContent content} originates: |
| * </p> |
| * <ul> |
| * <li><b>streamed</b>: The content is received from a stream, or |
| * generated on the fly. In particular, this category includes |
| * entities being received from a {@link HttpConnection connection}. |
| * {@link #isStreaming Streamed} entities are generally not |
| * {@link #isRepeatable repeatable}. |
| * </li> |
| * <li><b>self-contained</b>: The content is in memory or obtained by |
| * means that are independent from a connection or other entity. |
| * Self-contained entities are generally {@link #isRepeatable repeatable}. |
| * </li> |
| * <li><b>wrapping</b>: The content is obtained from another entity. |
| * </li> |
| * </ul> |
| * <p> |
| * This distinction is important for connection management with incoming |
| * entities. For entities that are created by an application and only sent |
| * using the HTTP components framework, the difference between streamed |
| * and self-contained is of little importance. In that case, it is suggested |
| * to consider non-repeatable entities as streamed, and those that are |
| * repeatable (without a huge effort) as self-contained. |
| * </p> |
| * |
| * @since 4.0 |
| */ |
| public interface HttpEntity extends EntityDetails, Closeable { |
| |
| /** |
| * Tells if the entity is capable of producing its data more than once. |
| * A repeatable entity's getContent() and writeTo(OutputStream) methods |
| * can be called more than once whereas a non-repeatable entity's can not. |
| * @return true if the entity is repeatable, false otherwise. |
| */ |
| boolean isRepeatable(); |
| |
| /** |
| * Returns a content stream of the entity. |
| * {@link #isRepeatable Repeatable} entities are expected |
| * to create a new instance of {@link InputStream} for each invocation |
| * of this method and therefore can be consumed multiple times. |
| * Entities that are not {@link #isRepeatable repeatable} are expected |
| * to return the same {@link InputStream} instance and therefore |
| * may not be consumed more than once. |
| * <p> |
| * IMPORTANT: Please note all entity implementations must ensure that |
| * all allocated resources are properly deallocated after |
| * the {@link InputStream#close()} method is invoked. |
| * </p> |
| * @return content stream of the entity. |
| * |
| * @throws IOException if the stream could not be created |
| * @throws UnsupportedOperationException |
| * if entity content cannot be represented as {@link java.io.InputStream}. |
| * |
| * @see #isRepeatable() |
| */ |
| InputStream getContent() throws IOException, UnsupportedOperationException; |
| |
| /** |
| * Writes the entity content out to the output stream. |
| * <p> |
| * IMPORTANT: Please note all entity implementations must ensure that |
| * all allocated resources are properly deallocated when this method |
| * returns. |
| * </p> |
| * |
| * @param outStream the output stream to write entity content to |
| * |
| * @throws IOException if an I/O error occurs |
| */ |
| void writeTo(OutputStream outStream) throws IOException; |
| |
| /** |
| * Tells whether this entity depends on an underlying stream. |
| * Streamed entities that read data directly from the socket should |
| * return {@code true}. Self-contained entities should return |
| * {@code false}. Wrapping entities should delegate this call |
| * to the wrapped entity. |
| * |
| * @return {@code true} if the entity content is streamed, |
| * {@code false} otherwise |
| */ |
| boolean isStreaming(); // don't expect an exception here |
| |
| /** |
| * Returns supplier of message trailers - headers sent after message body. |
| * May return {@code null} if trailers are not available. |
| * |
| * @since 5.0 |
| */ |
| Supplier<List<? extends Header>> getTrailers(); |
| |
| } |