public DocumentType getDocumentType() {
        return documentType;
    }
<p>A field update holds a list of value updates that will be applied atomically to a field in a document.</p>
<p>To create a field update that contains only a single value update, use the static factory methods provided by this
class.</p> <p>Example:</p>
<pre>
FieldUpdate clearFieldUpdate = FieldUpdate.createClearField(field);
</pre>
<p>It is also possible to create a field update that holds more than one value update.</p>
<p>Example:</p>
<pre>
FieldUpdate fieldUpdate = FieldUpdate.create(field);
ValueUpdate incrementValue = ValueUpdate.createIncrement("foo", 130d);
ValueUpdate addValue = ValueUpdate.createAdd("bar", 100);
fieldUpdate.addValueUpdate(incrementValue);
fieldUpdate.addValueUpdate(addValue);</pre>
<p>Note that the addValueUpdate() method returns a reference to itself to support chaining, so the last two
lines could be written as one:</p>
<pre>
fieldUpdate.addValueUpdate(incrementValue).addValueUpdate(addValue);
</pre>
<p>Note also that the second example above is equivalent to:</p>
<pre>
FieldUpdate fieldUpdate = FieldUpdate.createIncrement(field, "foo", 130d);
ValueUpdate addValue = ValueUpdate.createAdd("bar", 100);
fieldUpdate.addValueUpdate(addValue);
</pre>
<p>Note that even though updates take fields as arguments, those fields are not necessarily a field of a document
type - any name/value pair which existing in an updatable structure can be addressed by creating the Fields as
needed. For example:
<pre>
FieldUpdate field = FieldUpdate.createIncrement(new Field("myattribute",DataType.INT),130);
</pre>

@author Einar M R Rosenvinge
@see com.yahoo.document.update.ValueUpdate
@see com.yahoo.document.DocumentUpdate
document/src/main/java/com/yahoo/document/update/FieldUpdate.java