[[percolate]]
== Percolate API

The percolator allows to register queries against an index, and then
send `percolate` requests which include a doc, and getting back the
queries that match on that doc out of the set of registered queries.

Read the main {ref}/search-percolate.html[percolate]
documentation before reading this guide.

[source,java]
--------------------------------------------------
//This is the query we're registering in the percolator
QueryBuilder qb = termQuery("content", "amazing");

//Index the query = register it in the percolator
client.prepareIndex("_percolator", "myIndexName", "myDesignatedQueryName")
    .setSource(jsonBuilder()
        .startObject()
            .field("query", qb) // Register the query
        .endObject())
    .setRefresh(true) // Needed when the query shall be available immediately
    .execute().actionGet();
--------------------------------------------------

This indexes the above term query under the name
*myDesignatedQueryName*.

In order to check a document against the registered queries, use this
code:

[source,java]
--------------------------------------------------
//Build a document to check against the percolator
XContentBuilder docBuilder = XContentFactory.jsonBuilder().startObject();
docBuilder.field("doc").startObject(); //This is needed to designate the document
docBuilder.field("content", "This is amazing!");
docBuilder.endObject(); //End of the doc field
docBuilder.endObject(); //End of the JSON root object
//Percolate
PercolateResponse response = 
    client.preparePercolate("myIndexName", "myDocumentType").setSource(docBuilder).execute().actionGet();
//Iterate over the results
for(String result : response) {
    //Handle the result which is the name of
    //the query in the percolator
}
--------------------------------------------------