| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.services.io.FormatIdInputStream |
| 4 | |
| 5 | Copyright 1997, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.iapi.services.io; |
| 22 | |
| 23 | import java.io.DataInputStream; |
| 24 | import java.io.IOException; |
| 25 | import java.io.InputStream; |
| 26 | import java.io.ObjectInputStream; |
| 27 | import java.io.StreamCorruptedException; |
| 28 | import org.apache.derby.iapi.reference.SQLState; |
| 29 | import org.apache.derby.iapi.services.monitor.Monitor; |
| 30 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 31 | import org.apache.derby.iapi.error.StandardException; |
| 32 | import org.apache.derby.iapi.services.loader.ClassFactory; |
| 33 | import org.apache.derby.iapi.services.loader.ClassFactoryContext; |
| 34 | import org.apache.derby.iapi.types.Resetable; |
| 35 | |
| 36 | import org.apache.derby.iapi.services.context.ContextService; |
| 37 | /** |
| 38 | A stream for reading objects with format id tags which was |
| 39 | produced by a FormatIdOutputStream. |
| 40 | |
| 41 | <P>Please see the documentation for FormatIdOutputStream for |
| 42 | information about the streams format and capabilites. |
| 43 | */ |
| 44 | public final class FormatIdInputStream extends DataInputStream |
| 45 | implements ErrorObjectInput, Resetable |
| 46 | { |
| 47 | protected ClassFactory cf; |
| 48 | private ErrorInfo errorInfo; |
| 49 | private Exception myNestedException; |
| 50 | |
| 51 | |
| 52 | /** |
| 53 | Constructor for a FormatIdInputStream |
| 54 | |
| 55 | @param in bytes come from here. |
| 56 | */ |
| 57 | public FormatIdInputStream(InputStream in) |
| 58 | { |
| 59 | super(in); |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | Read an object from this stream. |
| 64 | |
| 65 | @return The read object. |
| 66 | @exception java.io.IOException An IO or serialization error occured. |
| 67 | @exception java.lang.ClassNotFoundException A class for an object in |
| 68 | the stream could not be found. |
| 69 | */ |
| 70 | |
| 71 | public Object readObject() throws IOException, ClassNotFoundException |
| 72 | { |
| 73 | setErrorInfo(null); |
| 74 | |
| 75 | int fmtId = FormatIdUtil.readFormatIdInteger(this); |
| 76 | |
| 77 | if (fmtId == StoredFormatIds.NULL_FORMAT_ID) |
| 78 | { |
| 79 | return null; |
| 80 | } |
| 81 | |
| 82 | if (fmtId == StoredFormatIds.STRING_FORMAT_ID) |
| 83 | { |
| 84 | return readUTF(); |
| 85 | } |
| 86 | |
| 87 | try |
| 88 | { |
| 89 | |
| 90 | if (fmtId == StoredFormatIds.SERIALIZABLE_FORMAT_ID) |
| 91 | { |
| 92 | ObjectInputStream ois = getObjectStream(); |
| 93 | try { |
| 94 | Object result = ois.readObject(); |
| 95 | return result; |
| 96 | } catch (IOException ioe) { |
| 97 | setErrorInfo((ErrorInfo) ois); |
| 98 | throw ioe; |
| 99 | } catch (ClassNotFoundException cnfe) { |
| 100 | setErrorInfo((ErrorInfo) ois); |
| 101 | throw cnfe; |
| 102 | } catch (LinkageError le) { |
| 103 | setErrorInfo((ErrorInfo) ois); |
| 104 | throw le; |
| 105 | } catch (ClassCastException cce) { |
| 106 | setErrorInfo((ErrorInfo) ois); |
| 107 | throw cce; |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | try { |
| 112 | |
| 113 | Formatable f = (Formatable)Monitor.newInstanceFromIdentifier(fmtId); |
| 114 | if (f instanceof Storable) |
| 115 | { |
| 116 | boolean isNull = this.readBoolean(); |
| 117 | if (isNull == true) |
| 118 | { |
| 119 | Storable s = (Storable)f; |
| 120 | s.restoreToNull(); |
| 121 | return s; |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | f.readExternal(this); |
| 126 | return f; |
| 127 | } catch (StandardException se) { |
| 128 | throw new ClassNotFoundException(se.toString()); |
| 129 | } |
| 130 | |
| 131 | |
| 132 | } |
| 133 | catch (ClassCastException cce) |
| 134 | { |
| 135 | // We catch this here as it is usuall a user error. |
| 136 | // they have readExternal (or SQLData) that doesn't match |
| 137 | // the writeExternal. and thus the object read is of |
| 138 | // the incorrect type, e.g. Integer i = (Integer) in.readObject(); |
| 139 | throw new StreamCorruptedException(cce.toString()); |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | Set the InputStream for this FormatIdInputStream to the stream |
| 145 | provided. |
| 146 | |
| 147 | @param in The new input stream. |
| 148 | */ |
| 149 | public void setInput(InputStream in) |
| 150 | { |
| 151 | this.in = in; |
| 152 | } |
| 153 | |
| 154 | public InputStream getInputStream() |
| 155 | { |
| 156 | return in; |
| 157 | } |
| 158 | |
| 159 | public String getErrorInfo() |
| 160 | { |
| 161 | if (errorInfo == null) |
| 162 | return ""; |
| 163 | |
| 164 | return errorInfo.getErrorInfo(); |
| 165 | } |
| 166 | |
| 167 | public Exception getNestedException() |
| 168 | { |
| 169 | if (myNestedException != null) |
| 170 | return null; |
| 171 | |
| 172 | if (errorInfo == null) |
| 173 | return null; |
| 174 | |
| 175 | return errorInfo.getNestedException(); |
| 176 | } |
| 177 | |
| 178 | private void setErrorInfo(ErrorInfo ei) |
| 179 | { |
| 180 | errorInfo = ei; |
| 181 | } |
| 182 | |
| 183 | |
| 184 | ClassFactory getClassFactory() { |
| 185 | if (cf == null) { |
| 186 | |
| 187 | ClassFactoryContext cfc = |
| 188 | (ClassFactoryContext) ContextService.getContextOrNull |
| 189 | (ClassFactoryContext.CONTEXT_ID); |
| 190 | |
| 191 | if (cfc != null) |
| 192 | cf = cfc.getClassFactory(); |
| 193 | } |
| 194 | return cf; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | ** Class private methods |
| 199 | */ |
| 200 | |
| 201 | private ObjectInputStream getObjectStream() throws IOException { |
| 202 | |
| 203 | return getClassFactory() == null ? |
| 204 | new ObjectInputStream(this) : |
| 205 | new ApplicationObjectInputStream(this, cf); |
| 206 | } |
| 207 | |
| 208 | |
| 209 | |
| 210 | /*** Resetable interface ***/ |
| 211 | |
| 212 | public void resetStream() |
| 213 | throws IOException, StandardException |
| 214 | { |
| 215 | if (SanityManager.DEBUG) |
| 216 | SanityManager.ASSERT(in instanceof Resetable); |
| 217 | ((Resetable) in).resetStream(); |
| 218 | } |
| 219 | |
| 220 | |
| 221 | public void initStream() |
| 222 | throws StandardException |
| 223 | { |
| 224 | if (SanityManager.DEBUG) |
| 225 | SanityManager.ASSERT(in instanceof Resetable); |
| 226 | ((Resetable) in).initStream(); |
| 227 | } |
| 228 | |
| 229 | |
| 230 | public void closeStream() |
| 231 | { |
| 232 | if (SanityManager.DEBUG) |
| 233 | SanityManager.ASSERT(in instanceof Resetable); |
| 234 | ((Resetable) in).closeStream(); |
| 235 | } |
| 236 | |
| 237 | } |
| 238 | |