1 | package org.greenstone.gatherer.util;
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2 |
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3 | import java.io.Reader;
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4 | import java.io.IOException;
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5 |
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6 | public class RemoveContentBeforeRootElementXMLReader extends Reader {
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7 |
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8 | static final byte[] xmlIndicator = "<?xml".getBytes();
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9 |
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10 | Reader ur;
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11 | int foundBytesReturned = 0;
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12 | boolean allFoundBytesReturned = false; //redundant, but may help performance
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13 |
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14 |
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15 | public RemoveContentBeforeRootElementXMLReader( Reader ur ) {
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16 |
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17 | this.ur = ur;
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18 |
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19 | //read up to the xml indicator
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20 | int foundBytes = 0;
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21 | int c = 0;
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22 | while ( c != -1 ) {
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23 | try {
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24 | c = ur.read();
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25 | } catch( Exception e ) {
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26 | System.err.println( "Exception while reading underlying Reader in RemoveContentBeforeRootElementXMLReader" );
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27 | }
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28 |
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29 | if ( c == (int)xmlIndicator[foundBytes] ) {
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30 | foundBytes++;
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31 | } else {
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32 | if ( foundBytes != 0 ) {
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33 | for ( int i=0; i<foundBytes; i++ ) {
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34 | System.out.print( (char)xmlIndicator[i] );
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35 | }
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36 | foundBytes = 0;
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37 | }
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38 | if ( c != -1 ) {
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39 | System.out.print( (char)c );
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40 | }
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41 | }
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42 |
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43 | if ( foundBytes == xmlIndicator.length ) {
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44 | return;
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45 | }
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46 |
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47 | }
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48 |
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49 | System.err.println( "RemoveContentBeforeRootElementXMLReader:\n" +
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50 | "The XML being loaded did not contain the '<?xml' string as expected" );
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51 | }
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52 |
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53 | public int read( char[] cbuf, int off, int len ) throws IOException {
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54 |
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55 | for ( int i=off; i<off+len && i<cbuf.length; i++ ) {
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56 |
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57 | //read from underlying reader
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58 | int c = read();
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59 |
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60 | //catch end of stream
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61 | if ( c == -1 ) {
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62 | if ( i == off ) {
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63 | return -1;
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64 | }
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65 | return i - off;
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66 | }
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67 |
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68 | //insert character into the array
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69 | cbuf[i] = (char)c;
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70 | }
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71 | return len;
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72 |
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73 | }
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74 |
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75 | public int read() throws IOException {
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76 |
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77 | if ( allFoundBytesReturned ) {
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78 | return ur.read();
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79 | }
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80 |
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81 | if ( foundBytesReturned < xmlIndicator.length ) {
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82 | return xmlIndicator[foundBytesReturned++];
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83 | }
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84 |
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85 | allFoundBytesReturned = true;
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86 | return ur.read();
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87 | }
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88 |
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89 | public void close() throws IOException {
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90 | ur.close();
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91 | }
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92 | }
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