org.apache.accumulo.examples.wikisearch.iterator
Class BooleanLogicIterator

java.lang.Object
  extended by org.apache.accumulo.examples.wikisearch.iterator.BooleanLogicIterator
All Implemented Interfaces:
OptionDescriber, SortedKeyValueIterator<Key,Value>

public class BooleanLogicIterator
extends Object
implements SortedKeyValueIterator<Key,Value>, OptionDescriber


Nested Class Summary
 class BooleanLogicIterator.BooleanLogicTreeNodeComparator
           
 
Nested classes/interfaces inherited from interface org.apache.accumulo.core.iterators.OptionDescriber
OptionDescriber.IteratorOptions
 
Field Summary
static String FIELD_INDEX_QUERY
           
static String FIELD_NAME_PREFIX
           
protected static org.apache.log4j.Logger log
           
protected  org.apache.hadoop.io.Text nullText
           
static String QUERY_OPTION
           
static String TERM_CARDINALITIES
           
 
Constructor Summary
BooleanLogicIterator()
           
BooleanLogicIterator(BooleanLogicIterator other, IteratorEnvironment env)
           
 
Method Summary
static void collapseBranches(BooleanLogicTreeNode myroot)
           
 SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env)
          Creates a deep copy of this iterator as though seek had not yet been called.
 OptionDescriber.IteratorOptions describeOptions()
          Gets an iterator options object that contains information needed to configure this iterator.
 Key getTopKey()
          Returns top key.
 Value getTopValue()
          Returns top value.
 boolean hasTop()
          Returns true if the iterator has more elements.
 void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env)
          init is responsible for setting up the iterator.
 void next()
          Advances to the next K,V pair.
 BooleanLogicTreeNode refactorTree(BooleanLogicTreeNode myroot)
           
 void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive)
          Seeks to the first key in the Range, restricting the resulting K,V pairs to those with the specified columns.
 void setDebug(org.apache.log4j.Level lev)
           
static void setLogLevel(org.apache.log4j.Level lev)
           
static void showBreadthFirstTraversal(BooleanLogicTreeNode root)
           
static void showDepthFirstTraversal(BooleanLogicTreeNode root)
          Small utility function to print out the depth-first enumeration of the tree.
 BooleanLogicTreeNode transformTreeNode(TreeNode node)
           
 boolean validateOptions(Map<String,String> options)
          Check to see if an options map contains all options required by an iterator and that the option values are in the expected formats.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

log

protected static final org.apache.log4j.Logger log

QUERY_OPTION

public static final String QUERY_OPTION
See Also:
Constant Field Values

TERM_CARDINALITIES

public static final String TERM_CARDINALITIES
See Also:
Constant Field Values

FIELD_INDEX_QUERY

public static final String FIELD_INDEX_QUERY
See Also:
Constant Field Values

FIELD_NAME_PREFIX

public static final String FIELD_NAME_PREFIX
See Also:
Constant Field Values

nullText

protected org.apache.hadoop.io.Text nullText
Constructor Detail

BooleanLogicIterator

public BooleanLogicIterator()

BooleanLogicIterator

public BooleanLogicIterator(BooleanLogicIterator other,
                            IteratorEnvironment env)
Method Detail

setLogLevel

public static void setLogLevel(org.apache.log4j.Level lev)

setDebug

public void setDebug(org.apache.log4j.Level lev)

deepCopy

public SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env)
Description copied from interface: SortedKeyValueIterator
Creates a deep copy of this iterator as though seek had not yet been called. init should be called on an iterator before deepCopy is called. init should not need to be called on the copy that is returned by deepCopy; that is, when necessary init should be called in the deepCopy method on the iterator it returns. The behavior is unspecified if init is called after deepCopy either on the original or the copy.

Specified by:
deepCopy in interface SortedKeyValueIterator<Key,Value>
Parameters:
env - IteratorEnvironment environment in which iterator is being run.
Returns:
SortedKeyValueIterator a copy of this iterator (with the same source and settings).

init

public void init(SortedKeyValueIterator<Key,Value> source,
                 Map<String,String> options,
                 IteratorEnvironment env)
          throws IOException
init is responsible for setting up the iterator. It will pull the serialized boolean parse tree from the options mapping and construct the appropriate sub-iterators Once initialized, this iterator will automatically seek to the first matching instance. If no top key exists, that means an event matching the boolean logic did not exist in the partition. Subsequent calls to next will move the iterator and all sub-iterators to the next match.

Specified by:
init in interface SortedKeyValueIterator<Key,Value>
Parameters:
source - The underlying SortedkeyValueIterator.
options - A Map of options.
env - The iterator environment
Throws:
IOException

transformTreeNode

public BooleanLogicTreeNode transformTreeNode(TreeNode node)
                                       throws org.apache.commons.jexl2.parser.ParseException
Throws:
org.apache.commons.jexl2.parser.ParseException

collapseBranches

public static void collapseBranches(BooleanLogicTreeNode myroot)
                             throws Exception
Throws:
Exception

refactorTree

public BooleanLogicTreeNode refactorTree(BooleanLogicTreeNode myroot)

showDepthFirstTraversal

public static void showDepthFirstTraversal(BooleanLogicTreeNode root)
Small utility function to print out the depth-first enumeration of the tree. Specify the root or sub root of the tree you wish to view.

Parameters:
root - The root node of the tree or sub-tree.

showBreadthFirstTraversal

public static void showBreadthFirstTraversal(BooleanLogicTreeNode root)

hasTop

public boolean hasTop()
Description copied from interface: SortedKeyValueIterator
Returns true if the iterator has more elements.

Specified by:
hasTop in interface SortedKeyValueIterator<Key,Value>
Returns:
true if the iterator has more elements.

getTopKey

public Key getTopKey()
Description copied from interface: SortedKeyValueIterator
Returns top key. Can be called 0 or more times without affecting behavior of next() or hasTop(). Note that in minor compaction scope and in non-full major compaction scopes the iterator may see deletion entries. These entries should be preserved by all iterators except ones that are strictly scan-time iterators that will never be configured for the minc or majc scopes. Deletion entries are only removed during full major compactions.

Specified by:
getTopKey in interface SortedKeyValueIterator<Key,Value>
Returns:
K

getTopValue

public Value getTopValue()
Description copied from interface: SortedKeyValueIterator
Returns top value. Can be called 0 or more times without affecting behavior of next() or hasTop().

Specified by:
getTopValue in interface SortedKeyValueIterator<Key,Value>
Returns:
V

next

public void next()
          throws IOException
Description copied from interface: SortedKeyValueIterator
Advances to the next K,V pair. Note that in minor compaction scope and in non-full major compaction scopes the iterator may see deletion entries. These entries should be preserved by all iterators except ones that are strictly scan-time iterators that will never be configured for the minc or majc scopes. Deletion entries are only removed during full major compactions.

Specified by:
next in interface SortedKeyValueIterator<Key,Value>
Throws:
IOException - if an I/O error occurs.

seek

public void seek(Range range,
                 Collection<ByteSequence> columnFamilies,
                 boolean inclusive)
          throws IOException
Description copied from interface: SortedKeyValueIterator
Seeks to the first key in the Range, restricting the resulting K,V pairs to those with the specified columns. An iterator does not have to stop at the end of the range. The whole range is provided so that iterators can make optimizations. Seek may be called multiple times with different parameters after SortedKeyValueIterator.init(org.apache.accumulo.core.iterators.SortedKeyValueIterator, java.util.Map, org.apache.accumulo.core.iterators.IteratorEnvironment) is called. Iterators that examine groups of adjacent key/value pairs (e.g. rows) to determine their top key and value should be sure that they properly handle a seek to a key in the middle of such a group (e.g. the middle of a row). Even if the client always seeks to a range containing an entire group (a,c), the tablet server could send back a batch of entries corresponding to (a,b], then reseek the iterator to range (b,c) when the scan is continued.

Specified by:
seek in interface SortedKeyValueIterator<Key,Value>
Parameters:
range - Range of keys to iterate over.
columnFamilies - Collection of column families to include or exclude.
inclusive - boolean that indicates whether to include (true) or exclude (false) column families.
Throws:
IOException - if an I/O error occurs.

describeOptions

public OptionDescriber.IteratorOptions describeOptions()
Description copied from interface: OptionDescriber
Gets an iterator options object that contains information needed to configure this iterator. This object will be used by the accumulo shell to prompt the user to input the appropriate information.

Specified by:
describeOptions in interface OptionDescriber
Returns:
an iterator options object

validateOptions

public boolean validateOptions(Map<String,String> options)
Description copied from interface: OptionDescriber
Check to see if an options map contains all options required by an iterator and that the option values are in the expected formats.

Specified by:
validateOptions in interface OptionDescriber
Parameters:
options - a map of option names to option values
Returns:
true if options are valid, false otherwise


Copyright © 2012 The Apache Software Foundation. All Rights Reserved.