AqpSyntaxParserAbstract.java

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

import org.antlr.runtime.TokenStream;
import org.apache.lucene.queryparser.flexible.core.QueryNodeParseException;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;

/**
 *  All ANTLR parsers should subclass {@link AqpSyntaxParser} and 
 *  provide two methods:
 *  
 *  {@link AqpSyntaxParser}{@link #getTokenStream(CharSequence)}
 *  {@link AqpSyntaxParser}{@link #parseTokenStream(TokenStream, CharSequence, CharSequence)}
 *  
 *  Optionally, the new class can also override
 *  
 *  {@link AqpSyntaxParser}{@link #initializeGrammar(String)}
 *  
 *  The default implementation is using reflection and is able
 *  to instantiate any grammar provided that the top parse rule
 *  is called <b>mainQ</b> and that the grammar is producing 
 *  AST tree.
 *
 */
public abstract class AqpSyntaxParserAbstract implements AqpSyntaxParser {

	/**
	 * Parse the query and return the {@link QueryNode}. ANTLR will 
	 * do the parsing and we return AST.
	 */
  public QueryNode parse(CharSequence query, CharSequence field)
      throws QueryNodeParseException {
    TokenStream tokens = getTokenStream(query);
    return parseTokenStream(tokens, query, field);
  }
}