[6785] | 1 | package org.greenstone.gatherer.util;
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| 2 |
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| 3 |
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| 4 | import java.io.BufferedReader;
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| 5 | import java.io.BufferedWriter;
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| 6 | import java.io.InputStreamReader;
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| 7 | import java.io.IOException;
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| 8 | import java.io.OutputStreamWriter;
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[8236] | 9 | import org.greenstone.gatherer.DebugStream;
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[6785] | 10 |
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| 11 |
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| 12 | /**
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| 13 | * This class provides a convenient method of running external programs and viewing/analysing
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| 14 | * their output. The external programs may be run with or without arguments.
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| 15 | */
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| 16 | public class ExternalProgram
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| 17 | {
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| 18 | private Process programProcess = null;
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| 19 |
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| 20 | private BufferedReader programOut = null;
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| 21 | private BufferedReader programErr = null;
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| 22 |
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| 23 |
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| 24 | /**
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| 25 | * Prepares to run a specified external program with the specified arguments.
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| 26 | *
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| 27 | * @param programName The name (and path, if necessary) of the program to run.
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| 28 | * @param programArgs The arguments to provide to the program when run.
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| 29 | */
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| 30 | public ExternalProgram(String programName, String programArgs)
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| 31 | throws IOException
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| 32 | {
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| 33 | // Run the program
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| 34 | programProcess = Runtime.getRuntime().exec(programName + " " + programArgs);
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| 35 |
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| 36 | // Grab the program output
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| 37 | programOut = new BufferedReader(new InputStreamReader(programProcess.getInputStream()));
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| 38 | programErr = new BufferedReader(new InputStreamReader(programProcess.getErrorStream()));
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| 39 |
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| 40 | }
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| 41 |
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| 42 |
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| 43 |
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| 44 | /**
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| 45 | */
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| 46 | public int exitProgram()
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| 47 | throws IOException
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| 48 | {
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| 49 | // Finished, thank you
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| 50 | //programIn.close();
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| 51 |
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| 52 | // Wait for the process to finish
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| 53 | try {
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| 54 | programProcess.waitFor();
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| 55 | }
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| 56 | catch (InterruptedException ex) {
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| 57 | throw new Error("Internal Error: Process interrupted.\n" + ex);
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| 58 | }
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| 59 |
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| 60 | // Return the program exit value
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| 61 | return programProcess.exitValue();
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| 62 | }
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| 63 |
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| 64 |
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| 65 | /**
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| 66 | * Returns a single line of output sent by the program to standard output.
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| 67 | *
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| 68 | * @return a single line of output sent by the program to standard output.
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| 69 | */
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| 70 | public String getLineOfProgramOutput()
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| 71 | {
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| 72 | // Read in a line from the program output
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| 73 | try {
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| 74 | if (programOut.ready())
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| 75 | return programOut.readLine();
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| 76 | else
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| 77 | return null;
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| 78 | }
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| 79 | catch (IOException ex) {
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[8236] | 80 | DebugStream.println("Error: Exception occurred while reading program output.");
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| 81 | DebugStream.println("Exception: " + ex);
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[6785] | 82 | return null;
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| 83 | }
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| 84 | }
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| 85 |
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| 86 |
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| 87 | /**
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| 88 | * Returns a single line of output sent by the program to standard error.
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| 89 | *
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| 90 | * @return a single line of output sent by the program to standard error.
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| 91 | */
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| 92 | public String getLineOfProgramError()
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| 93 | {
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| 94 | // Read in a line from the program error
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| 95 | try {
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| 96 | if (programErr.ready())
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| 97 | return programErr.readLine();
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| 98 | else
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| 99 | return null;
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| 100 | }
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| 101 | catch (IOException ex) {
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[8236] | 102 | DebugStream.println("Error: Exception occurred while reading program error.");
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| 103 | DebugStream.println("Exception: " + ex);
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[6785] | 104 | return null;
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| 105 | }
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| 106 | }
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| 107 | }
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