AqpFIELDProcessor.java

package org.apache.lucene.queryparser.flexible.aqp.processors;

import java.util.List;

import org.apache.lucene.queryparser.flexible.core.QueryNodeException;
import org.apache.lucene.queryparser.flexible.core.nodes.FieldableNode;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
import org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessor;
import org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessorImpl;
import org.apache.lucene.queryparser.flexible.standard.parser.EscapeQuerySyntaxImpl;
import org.apache.lucene.queryparser.flexible.aqp.nodes.AqpANTLRNode;
import org.apache.lucene.queryparser.flexible.aqp.util.AqpUtils;

/**
 * This processor applies the user-submitted value to all {@link FieldableNode}
 * nodes which are below it. The FIELD node itself will be discarded.
 * 
 * <p>
 * 
 * If the FIELD has only one child, the child will be returned
 * 
 * @see FieldableNode
 * @see AqpQNORMALProcessor and similar
 * 
 */
public class AqpFIELDProcessor extends QueryNodeProcessorImpl implements
    QueryNodeProcessor {

  @Override
  protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
    if (node instanceof AqpANTLRNode
        && ((AqpANTLRNode) node).getTokenLabel().equals("FIELD")) {
      if (node.getChildren().size() == 1) {
        return node.getChildren().get(0);
      }

      String field = getFieldValue(node);
      node = node.getChildren().get(node.getChildren().size() - 1);
      if (field != null) {
        AqpUtils.applyFieldToAllChildren(EscapeQuerySyntaxImpl.discardEscapeChar(field)
            .toString(), node);
      }
    }
    return node;
  }

  @Override
  protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
    return node;
  }

  @Override
  protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
      throws QueryNodeException {
    return children;
  }

  private String getFieldValue(QueryNode fieldNode) throws QueryNodeException {

    if (fieldNode != null && fieldNode.getChildren() != null) {
      return ((AqpANTLRNode) fieldNode.getChildren().get(0)).getTokenInput();
    }
    return null;
  }


}