001/* 002 * Copyright 2002-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.core.io; 018 019import java.io.ByteArrayInputStream; 020import java.io.IOException; 021import java.io.InputStream; 022import java.util.Arrays; 023 024import org.springframework.lang.Nullable; 025import org.springframework.util.Assert; 026 027/** 028 * {@link Resource} implementation for a given byte array. 029 * <p>Creates a {@link ByteArrayInputStream} for the given byte array. 030 * 031 * <p>Useful for loading content from any given byte array, 032 * without having to resort to a single-use {@link InputStreamResource}. 033 * Particularly useful for creating mail attachments from local content, 034 * where JavaMail needs to be able to read the stream multiple times. 035 * 036 * @author Juergen Hoeller 037 * @author Sam Brannen 038 * @since 1.2.3 039 * @see java.io.ByteArrayInputStream 040 * @see InputStreamResource 041 * @see org.springframework.mail.javamail.MimeMessageHelper#addAttachment(String, InputStreamSource) 042 */ 043public class ByteArrayResource extends AbstractResource { 044 045 private final byte[] byteArray; 046 047 private final String description; 048 049 050 /** 051 * Create a new {@code ByteArrayResource}. 052 * @param byteArray the byte array to wrap 053 */ 054 public ByteArrayResource(byte[] byteArray) { 055 this(byteArray, "resource loaded from byte array"); 056 } 057 058 /** 059 * Create a new {@code ByteArrayResource} with a description. 060 * @param byteArray the byte array to wrap 061 * @param description where the byte array comes from 062 */ 063 public ByteArrayResource(byte[] byteArray, @Nullable String description) { 064 Assert.notNull(byteArray, "Byte array must not be null"); 065 this.byteArray = byteArray; 066 this.description = (description != null ? description : ""); 067 } 068 069 070 /** 071 * Return the underlying byte array. 072 */ 073 public final byte[] getByteArray() { 074 return this.byteArray; 075 } 076 077 /** 078 * This implementation always returns {@code true}. 079 */ 080 @Override 081 public boolean exists() { 082 return true; 083 } 084 085 /** 086 * This implementation returns the length of the underlying byte array. 087 */ 088 @Override 089 public long contentLength() { 090 return this.byteArray.length; 091 } 092 093 /** 094 * This implementation returns a ByteArrayInputStream for the 095 * underlying byte array. 096 * @see java.io.ByteArrayInputStream 097 */ 098 @Override 099 public InputStream getInputStream() throws IOException { 100 return new ByteArrayInputStream(this.byteArray); 101 } 102 103 /** 104 * This implementation returns a description that includes the passed-in 105 * {@code description}, if any. 106 */ 107 @Override 108 public String getDescription() { 109 return "Byte array resource [" + this.description + "]"; 110 } 111 112 113 /** 114 * This implementation compares the underlying byte array. 115 * @see java.util.Arrays#equals(byte[], byte[]) 116 */ 117 @Override 118 public boolean equals(@Nullable Object other) { 119 return (this == other || (other instanceof ByteArrayResource && 120 Arrays.equals(((ByteArrayResource) other).byteArray, this.byteArray))); 121 } 122 123 /** 124 * This implementation returns the hash code based on the 125 * underlying byte array. 126 */ 127 @Override 128 public int hashCode() { 129 return (byte[].class.hashCode() * 29 * this.byteArray.length); 130 } 131 132}