[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | |
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| 19 | package org.apache.hadoop.ipc; |
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| 20 | |
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| 21 | import java.io.IOException; |
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| 22 | import java.lang.reflect.Constructor; |
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| 23 | |
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| 24 | import org.xml.sax.Attributes; |
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| 25 | import org.znerd.xmlenc.XMLOutputter; |
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| 26 | |
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| 27 | public class RemoteException extends IOException { |
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| 28 | /** For java.io.Serializable */ |
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| 29 | private static final long serialVersionUID = 1L; |
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| 30 | |
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| 31 | private String className; |
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| 32 | |
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| 33 | public RemoteException(String className, String msg) { |
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| 34 | super(msg); |
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| 35 | this.className = className; |
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| 36 | } |
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| 37 | |
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| 38 | public String getClassName() { |
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| 39 | return className; |
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| 40 | } |
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| 41 | |
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| 42 | /** |
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| 43 | * If this remote exception wraps up one of the lookupTypes |
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| 44 | * then return this exception. |
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| 45 | * <p> |
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| 46 | * Unwraps any IOException. |
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| 47 | * |
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| 48 | * @param lookupTypes the desired exception class. |
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| 49 | * @return IOException, which is either the lookupClass exception or this. |
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| 50 | */ |
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| 51 | public IOException unwrapRemoteException(Class<?>... lookupTypes) { |
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| 52 | if(lookupTypes == null) |
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| 53 | return this; |
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| 54 | for(Class<?> lookupClass : lookupTypes) { |
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| 55 | if(!lookupClass.getName().equals(getClassName())) |
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| 56 | continue; |
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| 57 | try { |
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| 58 | return instantiateException(lookupClass.asSubclass(IOException.class)); |
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| 59 | } catch(Exception e) { |
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| 60 | // cannot instantiate lookupClass, just return this |
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| 61 | return this; |
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| 62 | } |
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| 63 | } |
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| 64 | // wrapped up exception is not in lookupTypes, just return this |
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| 65 | return this; |
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| 66 | } |
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| 67 | |
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| 68 | /** |
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| 69 | * Instantiate and return the exception wrapped up by this remote exception. |
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| 70 | * |
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| 71 | * <p> This unwraps any <code>Throwable</code> that has a constructor taking |
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| 72 | * a <code>String</code> as a parameter. |
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| 73 | * Otherwise it returns this. |
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| 74 | * |
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| 75 | * @return <code>Throwable |
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| 76 | */ |
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| 77 | public IOException unwrapRemoteException() { |
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| 78 | try { |
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| 79 | Class<?> realClass = Class.forName(getClassName()); |
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| 80 | return instantiateException(realClass.asSubclass(IOException.class)); |
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| 81 | } catch(Exception e) { |
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| 82 | // cannot instantiate the original exception, just return this |
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| 83 | } |
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| 84 | return this; |
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| 85 | } |
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| 86 | |
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| 87 | private IOException instantiateException(Class<? extends IOException> cls) |
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| 88 | throws Exception { |
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| 89 | Constructor<? extends IOException> cn = cls.getConstructor(String.class); |
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| 90 | cn.setAccessible(true); |
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| 91 | String firstLine = this.getMessage(); |
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| 92 | int eol = firstLine.indexOf('\n'); |
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| 93 | if (eol>=0) { |
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| 94 | firstLine = firstLine.substring(0, eol); |
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| 95 | } |
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| 96 | IOException ex = cn.newInstance(firstLine); |
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| 97 | ex.initCause(this); |
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| 98 | return ex; |
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| 99 | } |
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| 100 | |
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| 101 | /** Write the object to XML format */ |
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| 102 | public void writeXml(String path, XMLOutputter doc) throws IOException { |
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| 103 | doc.startTag(RemoteException.class.getSimpleName()); |
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| 104 | doc.attribute("path", path); |
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| 105 | doc.attribute("class", getClassName()); |
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| 106 | String msg = getLocalizedMessage(); |
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| 107 | int i = msg.indexOf("\n"); |
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| 108 | if (i >= 0) { |
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| 109 | msg = msg.substring(0, i); |
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| 110 | } |
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| 111 | doc.attribute("message", msg.substring(msg.indexOf(":") + 1).trim()); |
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| 112 | doc.endTag(); |
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| 113 | } |
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| 114 | |
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| 115 | /** Create RemoteException from attributes */ |
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| 116 | public static RemoteException valueOf(Attributes attrs) { |
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| 117 | return new RemoteException(attrs.getValue("class"), |
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| 118 | attrs.getValue("message")); |
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| 119 | } |
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| 120 | } |
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