001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.camel.converter.stream; 018 019 import java.io.File; 020 import java.io.FileInputStream; 021 import java.io.FileNotFoundException; 022 import java.io.IOException; 023 import java.io.InputStream; 024 import java.io.OutputStream; 025 import java.nio.channels.Channels; 026 import java.nio.channels.FileChannel; 027 import java.nio.channels.WritableByteChannel; 028 029 import org.apache.camel.RuntimeCamelException; 030 import org.apache.camel.StreamCache; 031 import org.apache.camel.util.IOHelper; 032 033 public class FileInputStreamCache extends InputStream implements StreamCache { 034 private InputStream stream; 035 private File file; 036 037 public FileInputStreamCache(File file) throws FileNotFoundException { 038 this.file = file; 039 this.stream = null; 040 } 041 042 @Override 043 public void close() { 044 if (stream != null) { 045 IOHelper.close(stream); 046 } 047 } 048 049 @Override 050 public void reset() { 051 // reset by closing and creating a new stream based on the file 052 close(); 053 // reset by creating a new stream based on the file 054 stream = null; 055 056 if (!file.exists()) { 057 throw new RuntimeCamelException("Cannot reset stream from file " + file); 058 } 059 } 060 061 public void writeTo(OutputStream os) throws IOException { 062 if (stream == null) { 063 FileInputStream s = new FileInputStream(file); 064 long len = file.length(); 065 WritableByteChannel out; 066 if (os instanceof WritableByteChannel) { 067 out = (WritableByteChannel)os; 068 } else { 069 out = Channels.newChannel(os); 070 } 071 FileChannel fc = s.getChannel(); 072 long pos = 0; 073 while (pos < len) { 074 long i = fc.transferTo(pos, len - pos, out); 075 pos += i; 076 } 077 s.close(); 078 } else { 079 IOHelper.copy(getInputStream(), os); 080 } 081 } 082 083 @Override 084 public int available() throws IOException { 085 return getInputStream().available(); 086 } 087 088 @Override 089 public int read() throws IOException { 090 return getInputStream().read(); 091 } 092 093 protected InputStream getInputStream() throws IOException { 094 if (stream == null) { 095 stream = IOHelper.buffered(new FileInputStream(file)); 096 } 097 return stream; 098 } 099 }