## org.apache.lucene.search.grouping
Class AbstractAllGroupHeadsCollector.GroupHead<GROUP_VALUE_TYPE>

    java.lang.Object
      org.apache.lucene.search.grouping.AbstractAllGroupHeadsCollector.GroupHead<GROUP_VALUE_TYPE>

Direct Known Subclasses:
  FunctionAllGroupHeadsCollector.GroupHead

Enclosing class:
  AbstractAllGroupHeadsCollector<GH extends AbstractAllGroupHeadsCollector.GroupHead>

    public abstract static class AbstractAllGroupHeadsCollector.GroupHead<GROUP_VALUE_TYPE>

extends Object

Represents a group head. A group head is the most relevant document for a particular group. The relevancy is based is usually based on the sort. The group head contains a group value with its associated most relevant document id.

Field Summary
`int` `doc`
`GROUP_VALUE_TYPE` `groupValue`

Constructor Summary
`protected` `AbstractAllGroupHeadsCollector.GroupHead(GROUP_VALUE_TYPE groupValue, int doc)`

Method Summary
`protected abstract int` `compare(int compIDX, int doc)` Compares the specified document for a specified comparator against the current most relevant document.
`protected abstract void` `updateDocHead(int doc)` Updates the current most relevant document with the specified document.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### groupValue

    public final GROUP_VALUE_TYPE groupValue

### doc

    public int doc

Constructor Detail

### AbstractAllGroupHeadsCollector.GroupHead

    protected AbstractAllGroupHeadsCollector.GroupHead(GROUP_VALUE_TYPE groupValue,
                                                       int doc)

Method Detail

### compare

    protected abstract int compare(int compIDX,
                                   int doc)
                            throws IOException

  Compares the specified document for a specified comparator against the current most relevant document.

  Parameters:
    `compIDX` - The comparator index of the specified comparator.
    `doc` - The specified document.
  Returns:
    -1 if the specified document wasn't competitive against the current most relevant document, 1 if the specified document was competitive against the current most relevant document. Otherwise 0.
  Throws:
    `IOException` - If I/O related errors occur

### updateDocHead

    protected abstract void updateDocHead(int doc)
                                   throws IOException

  Updates the current most relevant document with the specified document.

  Parameters:
    `doc` - The specified document
  Throws:
    `IOException` - If I/O related errors occur

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