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 | #ifndef LIBHDFS_JNI_HELPER_H |
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20 | #define LIBHDFS_JNI_HELPER_H |
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21 | |
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22 | #include <jni.h> |
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23 | #include <stdio.h> |
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24 | |
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25 | #include <stdlib.h> |
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26 | #include <stdarg.h> |
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27 | #include <search.h> |
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28 | #include <pthread.h> |
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29 | #include <errno.h> |
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30 | |
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31 | #define PATH_SEPARATOR ':' |
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32 | |
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33 | #define USER_CLASSPATH "/home/y/libexec/hadoop/conf:/home/y/libexec/hadoop/lib/hadoop-0.1.0.jar" |
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34 | |
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35 | |
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36 | /** Denote the method we want to invoke as STATIC or INSTANCE */ |
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37 | typedef enum { |
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38 | STATIC, |
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39 | INSTANCE |
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40 | } MethType; |
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41 | |
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42 | |
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43 | /** Used for returning an appropriate return value after invoking |
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44 | * a method |
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45 | */ |
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46 | typedef jvalue RetVal; |
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47 | |
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48 | /** Used for returning the exception after invoking a method */ |
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49 | typedef jthrowable Exc; |
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50 | |
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51 | /** invokeMethod: Invoke a Static or Instance method. |
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52 | * className: Name of the class where the method can be found |
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53 | * methName: Name of the method |
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54 | * methSignature: the signature of the method "(arg-types)ret-type" |
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55 | * methType: The type of the method (STATIC or INSTANCE) |
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56 | * instObj: Required if the methType is INSTANCE. The object to invoke |
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57 | the method on. |
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58 | * env: The JNIEnv pointer |
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59 | * retval: The pointer to a union type which will contain the result of the |
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60 | method invocation, e.g. if the method returns an Object, retval will be |
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61 | set to that, if the method returns boolean, retval will be set to the |
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62 | value (JNI_TRUE or JNI_FALSE), etc. |
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63 | * exc: If the methods throws any exception, this will contain the reference |
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64 | * Arguments (the method arguments) must be passed after methSignature |
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65 | * RETURNS: -1 on error and 0 on success. If -1 is returned, exc will have |
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66 | a valid exception reference, and the result stored at retval is undefined. |
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67 | */ |
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68 | int invokeMethod(JNIEnv *env, RetVal *retval, Exc *exc, MethType methType, |
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69 | jobject instObj, const char *className, const char *methName, |
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70 | const char *methSignature, ...); |
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71 | |
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72 | /** constructNewObjectOfClass: Invoke a constructor. |
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73 | * className: Name of the class |
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74 | * ctorSignature: the signature of the constructor "(arg-types)V" |
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75 | * env: The JNIEnv pointer |
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76 | * exc: If the ctor throws any exception, this will contain the reference |
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77 | * Arguments to the ctor must be passed after ctorSignature |
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78 | */ |
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79 | jobject constructNewObjectOfClass(JNIEnv *env, Exc *exc, const char *className, |
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80 | const char *ctorSignature, ...); |
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81 | |
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82 | jmethodID methodIdFromClass(const char *className, const char *methName, |
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83 | const char *methSignature, MethType methType, |
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84 | JNIEnv *env); |
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85 | |
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86 | jclass globalClassReference(const char *className, JNIEnv *env); |
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87 | |
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88 | /** classNameOfObject: Get an object's class name. |
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89 | * @param jobj: The object. |
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90 | * @param env: The JNIEnv pointer. |
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91 | * @return Returns a pointer to a string containing the class name. This string |
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92 | * must be freed by the caller. |
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93 | */ |
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94 | char *classNameOfObject(jobject jobj, JNIEnv *env); |
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95 | |
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96 | /** getJNIEnv: A helper function to get the JNIEnv* for the given thread. |
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97 | * If no JVM exists, then one will be created. JVM command line arguments |
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98 | * are obtained from the LIBHDFS_OPTS environment variable. |
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99 | * @param: None. |
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100 | * @return The JNIEnv* corresponding to the thread. |
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101 | * */ |
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102 | JNIEnv* getJNIEnv(void); |
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103 | |
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104 | jarray constructNewArrayString(JNIEnv *env, Exc *exc, const char **elements, int size) ; |
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105 | |
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106 | #endif /*LIBHDFS_JNI_HELPER_H*/ |
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107 | |
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108 | /** |
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109 | * vim: ts=4: sw=4: et: |
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110 | */ |
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111 | |
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