org.apache.hadoop.io.Text#charAt ( )源码实例Demo

protected boolean isEventKey(Key k) {
    Text cf = k.getColumnFamily();
    return cf.getLength() > 0
                    && cf.find("\u0000") != -1
                    && !((cf.charAt(0) == 'f' && cf.charAt(1) == 'i' && cf.charAt(2) == 0) || (cf.getLength() == 1 && cf.charAt(0) == 'd') || (cf
                                    .getLength() == 2 && cf.charAt(0) == 't' && cf.charAt(1) == 'f'));
}
 

boolean isEventKey(Key k) {
    Text cf = k.getColumnFamily();
    return cf.getLength() > 0
                    && cf.find("\u0000") != -1
                    && !((cf.charAt(0) == 'f' && cf.charAt(1) == 'i' && cf.charAt(2) == 0) || (cf.getLength() == 1 && cf.charAt(0) == 'd') || (cf
                                    .getLength() == 2 && cf.charAt(0) == 't' && cf.charAt(1) == 'f'));
}
 

private boolean isNextMetricTheSame(Text nextRow) {
    byte[] next = nextRow.getBytes();
    if (next.length > prevMetricBytes.getLength()
            && 0 == prevMetricBytes.compareTo(next, 0, prevMetricBytes.getLength())
            && nextRow.charAt(prevMetricBytes.getLength()) == 0x00) {
        return true;
    } else {
        return false;
    }
}
 

public void reduce(
        Text key,
        Iterator<Text> iter, 
        OutputCollector<Text, Text> oc,
        Reporter reporter) throws IOException {
    // For each value, figure out which file it's from and store it
    // accordingly.
    List<String> first = new ArrayList<String>();
    List<String> second = new ArrayList<String>();

    while (iter.hasNext()) {
        Text txt = iter.next();
        if (txt.charAt(0) == '1') {
            first.add(txt.toString().substring(1));
        }
        else second.add(txt.toString().substring(1));
        reporter.setStatus("OK");
    }

    reporter.setStatus("OK");

    if (first.size() == 0) return;
    if (second.size() == 0) second.add(null);

    // Do the cross product
    for (String s1 : first) {
        for (String s2 : second) {
            if (s2==null) oc.collect(null, new Text(key + "\t" + s1 + "\t\t"));
            else oc.collect(null, new Text(key + "\t" + s1 + "\t" + key + "\t" + s2));
        }
    }
    first.clear();
}
 

/**
 * Natively parses a text object into a long with the specified radix.
 * 
 * @param text
 * @param radix
 * @return
 * @throws NumberFormatException
 */
public static long parseLong(Text text, int radix) throws NumberFormatException {
    if (text == null) {
        throw new NumberFormatException("null");
    }
    
    if (radix < Character.MIN_RADIX) {
        throw new NumberFormatException("radix " + radix + " less than Character.MIN_RADIX");
    }
    if (radix > Character.MAX_RADIX) {
        throw new NumberFormatException("radix " + radix + " greater than Character.MAX_RADIX");
    }
    
    long result = 0;
    boolean negative = false;
    int i = 0, max = text.getLength();
    long limit;
    long multmin;
    int digit;
    
    if (max > 0) {
        if (text.charAt(0) == '-') {
            negative = true;
            limit = Long.MIN_VALUE;
            i++;
        } else {
            limit = -Long.MAX_VALUE;
        }
        multmin = limit / radix;
        if (i < max) {
            digit = Character.digit(text.charAt(i++), radix);
            if (digit < 0) {
                throw new NumberFormatException();
            } else {
                result = -digit;
            }
        }
        while (i < max) {
            // Accumulating negatively avoids surprises near MAX_VALUE
            digit = Character.digit(text.charAt(i++), radix);
            if (digit < 0) {
                throw new NumberFormatException();
            }
            if (result < multmin) {
                throw new NumberFormatException();
            }
            result *= radix;
            if (result < limit + digit) {
                throw new NumberFormatException();
            }
            result -= digit;
        }
    } else {
        throw new NumberFormatException();
    }
    if (negative) {
        if (i > 1) {
            return result;
        } else { /* Only got "-" */
            throw new NumberFormatException();
        }
    } else {
        return -result;
    }
}
 

private boolean isFieldIndexKey(Key key) {
    Text cf = key.getColumnFamily();
    return (cf.getLength() >= 3 && cf.charAt(0) == 'f' && cf.charAt(1) == 'i' && cf.charAt(2) == '\0');
}
 

protected void findNextDocument() {
    topKey = null;
    
    try {
        Text cf = new Text();
        
        /*
         * Given that we are already at a document key, this method will continue to advance the underlying source until it is either exhausted (hasTop()
         * returns false), the returned key is not in the totalRange, and the current top key shares the same row and column family as the source's next
         * key.
         */
        while (topKey == null && source.hasTop()) {
            Key k = source.getTopKey();
            if (log.isTraceEnabled())
                log.trace("Sought to " + k);
            k.getColumnFamily(cf);
            
            if (!isEventKey(k)) {
                if (cf.find("fi\0") == 0) {
                    if (log.isDebugEnabled()) {
                        log.debug("Seeking over 'fi')");
                    }
                    // Try to do an optimized jump over the field index
                    cf.set("fi\1");
                    source.seek(new Range(new Key(source.getTopKey().getRow(), cf), false, totalRange.getEndKey(), totalRange.isEndKeyInclusive()),
                                    columnFamilies, inclusive);
                } else if (cf.getLength() == 1 && cf.charAt(0) == 'd') {
                    if (log.isDebugEnabled()) {
                        log.debug("Seeking over 'd'");
                    }
                    // Try to do an optimized jump over the raw documents
                    cf.set("d\0");
                    source.seek(new Range(new Key(source.getTopKey().getRow(), cf), false, totalRange.getEndKey(), totalRange.isEndKeyInclusive()),
                                    columnFamilies, inclusive);
                } else if (cf.getLength() == 2 && cf.charAt(0) == 't' && cf.charAt(1) == 'f') {
                    if (log.isDebugEnabled()) {
                        log.debug("Seeking over 'tf'");
                    }
                    // Try to do an optimized jump over the term frequencies
                    cf.set("tf\0");
                    source.seek(new Range(new Key(source.getTopKey().getRow(), cf), false, totalRange.getEndKey(), totalRange.isEndKeyInclusive()),
                                    columnFamilies, inclusive);
                } else {
                    if (log.isDebugEnabled()) {
                        log.debug("Next()'ing over the current key");
                    }
                    source.next();
                }
            } else {
                if (dataTypeFilter.apply(source.getTopKey())) {
                    this.topKey = source.getTopKey();
                } else {
                    Range nextCF = new Range(nextStartKey(source.getTopKey()), true, totalRange.getEndKey(), totalRange.isEndKeyInclusive());
                    source.seek(nextCF, columnFamilies, inclusive);
                }
            }
        }
    } catch (IOException e) {
        throw new RuntimeException("Could not seek in findNextDocument", e);
    }
}
 

private boolean isFieldIndexKey(Key key) {
    Text cf = key.getColumnFamily();
    return (cf.getLength() >= 3 && cf.charAt(0) == 'f' && cf.charAt(1) == 'i' && cf.charAt(2) == '\0');
}