1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package java.io; 19 20 /** 21 * Defines an interface for classes that allow reading serialized objects. 22 * 23 * @see ObjectInputStream 24 * @see ObjectOutput 25 */ 26 public interface ObjectInput extends DataInput, AutoCloseable { 27 /** 28 * Indicates the number of bytes of primitive data that can be read without 29 * blocking. 30 * 31 * @return the number of bytes available. 32 * @throws IOException 33 * if an I/O error occurs. 34 */ available()35 public int available() throws IOException; 36 37 /** 38 * Closes this stream. Implementations of this method should free any 39 * resources used by the stream. 40 * 41 * @throws IOException 42 * if an I/O error occurs while closing the input stream. 43 */ close()44 public void close() throws IOException; 45 46 /** 47 * Reads a single byte from this stream and returns it as an integer in the 48 * range from 0 to 255. Returns -1 if the end of this stream has been 49 * reached. Blocks if no input is available. 50 * 51 * @return the byte read or -1 if the end of this stream has been reached. 52 * @throws IOException 53 * if this stream is closed or another I/O error occurs. 54 */ read()55 public int read() throws IOException; 56 57 /** 58 * Reads bytes from this stream into the byte array {@code buffer}. Blocks 59 * while waiting for input. 60 * 61 * @param buffer 62 * the array in which to store the bytes read. 63 * @return the number of bytes read or -1 if the end of this stream has been 64 * reached. 65 * @throws IOException 66 * if this stream is closed or another I/O error occurs. 67 */ read(byte[] buffer)68 public int read(byte[] buffer) throws IOException; 69 70 /** 71 * Reads at most {@code count} bytes from this stream and stores them in 72 * byte array {@code buffer} starting at offset {@code count}. Blocks while 73 * waiting for input. 74 * 75 * @param buffer 76 * the array in which to store the bytes read. 77 * @param offset 78 * the initial position in {@code buffer} to store the bytes read 79 * from this stream. 80 * @param count 81 * the maximum number of bytes to store in {@code buffer}. 82 * @return the number of bytes read or -1 if the end of this stream has been 83 * reached. 84 * @throws IOException 85 * if this stream is closed or another I/O error occurs. 86 */ read(byte[] buffer, int offset, int count)87 public int read(byte[] buffer, int offset, int count) throws IOException; 88 89 /** 90 * Reads the next object from this stream. 91 * 92 * @return the object read. 93 * 94 * @throws ClassNotFoundException 95 * if the object's class cannot be found. 96 * @throws IOException 97 * if this stream is closed or another I/O error occurs. 98 */ readObject()99 public Object readObject() throws ClassNotFoundException, IOException; 100 101 /** 102 * Skips {@code byteCount} bytes on this stream. Less than {@code byteCount} byte are 103 * skipped if the end of this stream is reached before the operation 104 * completes. 105 * 106 * @return the number of bytes actually skipped. 107 * @throws IOException 108 * if this stream is closed or another I/O error occurs. 109 */ skip(long byteCount)110 public long skip(long byteCount) throws IOException; 111 } 112