AqpFuzzyModifierNode.java

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

import org.apache.lucene.queryparser.flexible.messages.MessageImpl;
import org.apache.lucene.queryparser.flexible.aqp.processors.AqpFuzzyModifierProcessor;
import org.apache.lucene.queryparser.flexible.core.QueryNodeError;
import org.apache.lucene.queryparser.flexible.core.messages.QueryParserMessages;
import org.apache.lucene.queryparser.flexible.core.nodes.ModifierQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNodeImpl;
import org.apache.lucene.queryparser.flexible.core.parser.EscapeQuerySyntax;

/**
 *  {@link AqpFuzzyModifierNode} is consumed by the {@link AqpFuzzyModifierProcessor}
 *  which will decide what is the appropriate operation for '~' operator. E.g.
 *  
 *  <pre>
 *  
 *    "foo bar"~5  == slop query node
 *    "foo"~5      == fuzzy search for 'foo' 
 *  </pre>
 */
public class AqpFuzzyModifierNode extends QueryNodeImpl implements QueryNode {

  private static final long serialVersionUID = -3059874057254791689L;
  private Float fuzzy;

  public AqpFuzzyModifierNode(QueryNode query, Float fuzzy) {
    if (query == null) {
      throw new QueryNodeError(new MessageImpl(
          QueryParserMessages.PARAMETER_VALUE_NOT_SUPPORTED, "query", "null"));
    }

    allocate();
    setLeaf(false);
    add(query);
    this.fuzzy = fuzzy;
  }

  public CharSequence toQueryString(EscapeQuerySyntax escapeSyntaxParser) {
    if (getChild() == null)
      return "";

    String leftParenthensis = "";
    String rightParenthensis = "";

    if (getChild() != null && getChild() instanceof ModifierQueryNode) {
      leftParenthensis = "(";
      rightParenthensis = ")";
    }

    return leftParenthensis + getChild().toQueryString(escapeSyntaxParser)
        + rightParenthensis + "~" + this.fuzzy.toString();

  }

  public String toString() {
    return "<fuzzy value='" + this.fuzzy.toString() + "'>" + "\n"
        + getChild().toString() + "\n</fuzzy>";
  }

  public QueryNode getChild() {
    return getChildren().get(0);
  }

  public Float getFuzzyValue() {
    return fuzzy;
  }

}