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 */ 017package org.apache.camel.util; 018 019import java.io.ByteArrayOutputStream; 020import java.io.Closeable; 021import java.io.IOException; 022import java.io.InputStream; 023import java.util.Iterator; 024import java.util.Scanner; 025 026import org.apache.camel.CamelContext; 027import org.apache.camel.NoTypeConversionAvailableException; 028 029/** 030 * Group based {@link Iterator} which groups the given {@link Iterator} a number of times 031 * and then return a combined response as a String. 032 * <p/> 033 * This implementation uses as internal byte array buffer, to combine the response. 034 * The token is inserted between the individual parts. 035 * <p/> 036 * For example if you group by new line, then a new line token is inserted between the lines. 037 */ 038public final class GroupIterator implements Iterator<Object>, Closeable { 039 040 private final CamelContext camelContext; 041 private final Iterator<?> it; 042 private final String token; 043 private final int group; 044 private boolean closed; 045 private final ByteArrayOutputStream bos = new ByteArrayOutputStream(); 046 047 /** 048 * Creates a new group iterator 049 * 050 * @param camelContext the camel context 051 * @param it the iterator to group 052 * @param token then token used to separate between the parts, use <tt>null</tt> to not add the token 053 * @param group number of parts to group together 054 * @throws IllegalArgumentException is thrown if group is not a positive number 055 */ 056 public GroupIterator(CamelContext camelContext, Iterator<?> it, String token, int group) { 057 this.camelContext = camelContext; 058 this.it = it; 059 this.token = token; 060 this.group = group; 061 if (group <= 0) { 062 throw new IllegalArgumentException("Group must be a positive number, was: " + group); 063 } 064 } 065 066 @Override 067 public void close() throws IOException { 068 try { 069 if (it instanceof Scanner) { 070 // special for Scanner which implement the Closeable since JDK7 071 Scanner scanner = (Scanner) it; 072 scanner.close(); 073 IOException ioException = scanner.ioException(); 074 if (ioException != null) { 075 throw ioException; 076 } 077 } else if (it instanceof Closeable) { 078 IOHelper.closeWithException((Closeable) it); 079 } 080 } finally { 081 // close the buffer as well 082 bos.close(); 083 // we are now closed 084 closed = true; 085 } 086 } 087 088 @Override 089 public boolean hasNext() { 090 if (closed) { 091 return false; 092 } 093 094 boolean answer = it.hasNext(); 095 if (!answer) { 096 // auto close 097 try { 098 close(); 099 } catch (IOException e) { 100 // ignore 101 } 102 } 103 return answer; 104 } 105 106 @Override 107 public Object next() { 108 try { 109 return doNext(); 110 } catch (Exception e) { 111 throw ObjectHelper.wrapRuntimeCamelException(e); 112 } 113 } 114 115 private Object doNext() throws IOException, NoTypeConversionAvailableException { 116 int count = 0; 117 Object data = ""; 118 while (count < group && it.hasNext()) { 119 data = it.next(); 120 121 // include token in between 122 if (data != null && count > 0 && token != null) { 123 bos.write(token.getBytes()); 124 } 125 if (data instanceof InputStream) { 126 InputStream is = (InputStream) data; 127 IOHelper.copy(is, bos); 128 } else if (data instanceof byte[]) { 129 byte[] bytes = (byte[]) data; 130 bos.write(bytes); 131 } else if (data != null) { 132 // convert to input stream 133 InputStream is = camelContext.getTypeConverter().mandatoryConvertTo(InputStream.class, data); 134 IOHelper.copy(is, bos); 135 } 136 137 count++; 138 } 139 140 // prepare and return answer as String 141 String answer = bos.toString(); 142 bos.reset(); 143 return answer; 144 } 145 146 @Override 147 public void remove() { 148 it.remove(); 149 } 150}