http://hibernate.org: The core O/RM functionality as provided by Hibernate (Hibernate.org) 
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 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, 2013, Red Hat Inc. or third-party contributors as
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 * for more details.
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 * You should have received a copy of the GNU Lesser General Public License
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 */
package org.hibernate.engine.query.spi;

import org.hibernate.QueryException;
import org.hibernate.hql.internal.classic.ParserHelper;
import org.hibernate.internal.util.StringHelper;


The single available method parse is responsible for parsing a query string and recognizing tokens in relation to parameters (either named, JPA-style, or ordinal) and providing callbacks about such recognitions. 
Author:Steve Ebersole
/**
 * The single available method {@link #parse} is responsible for parsing a
 * query string and recognizing tokens in relation to parameters (either
 * named, JPA-style, or ordinal) and providing callbacks about such
 * recognitions.
 *
 * @author Steve Ebersole
 */
public class ParameterParser {
	
Maybe better named a Journaler.  Essentially provides a callback contract for things that recognize parameters

/**
	 * Maybe better named a Journaler.  Essentially provides a callback contract for things that recognize parameters
	 */
	public static interface Recognizer {
		
Called when an output parameter is recognized

Params:
  • position – The position within the query
/**
		 * Called when an output parameter is recognized
		 *
		 * @param position The position within the query
		 */
		public void outParameter(int position);

		
Called when an ordinal parameter is recognized

Params:
  • position – The position within the query
/**
		 * Called when an ordinal parameter is recognized
		 *
		 * @param position The position within the query
		 */
		public void ordinalParameter(int position);

		
Called when a named parameter is recognized

Params:
  • name – The recognized parameter name
  • position – The position within the query
/**
		 * Called when a named parameter is recognized
		 *
		 * @param name The recognized parameter name
		 * @param position The position within the query
		 */
		public void namedParameter(String name, int position);

		
Called when a JPA-style named parameter is recognized

Params:
  • name – The name of the JPA-style parameter
  • position – The position within the query
/**
		 * Called when a JPA-style named parameter is recognized
		 *
		 * @param name The name of the JPA-style parameter
		 * @param position The position within the query
		 */
		public void jpaPositionalParameter(String name, int position);

		
Called when a character that is not a parameter (or part of a parameter dfinition) is recognized.

Params:
  • character – The recognized character
/**
		 * Called when a character that is not a parameter (or part of a parameter dfinition) is recognized.
		 *
		 * @param character The recognized character
		 */
		public void other(char character);
	}

	
Direct instantiation of ParameterParser disallowed.

/**
	 * Direct instantiation of ParameterParser disallowed.
	 */
	private ParameterParser() {
	}

	
Performs the actual parsing and tokenizing of the query string making appropriate
callbacks to the given recognizer upon recognition of the various tokens.


Note that currently, this only knows how to deal with a single output
parameter (for callable statements).  If we later add support for
multiple output params, this, obviously, needs to change.

Params:
  • sqlString – The string to be parsed/tokenized.
  • recognizer – The thing which handles recognition events.
Throws:
/**
	 * Performs the actual parsing and tokenizing of the query string making appropriate
	 * callbacks to the given recognizer upon recognition of the various tokens.
	 * <p/>
	 * Note that currently, this only knows how to deal with a single output
	 * parameter (for callable statements).  If we later add support for
	 * multiple output params, this, obviously, needs to change.
	 *
	 * @param sqlString The string to be parsed/tokenized.
	 * @param recognizer The thing which handles recognition events.
	 * @throws QueryException Indicates unexpected parameter conditions.
	 */
	public static void parse(String sqlString, Recognizer recognizer) throws QueryException {
		final boolean hasMainOutputParameter = startsWithEscapeCallTemplate( sqlString );
		boolean foundMainOutputParam = false;

		final int stringLength = sqlString.length();
		boolean inQuote = false;
		for ( int indx = 0; indx < stringLength; indx++ ) {
			final char c = sqlString.charAt( indx );
			if ( inQuote ) {
				if ( '\'' == c ) {
					inQuote = false;
				}
				recognizer.other( c );
			}
			else if ( '\'' == c ) {
				inQuote = true;
				recognizer.other( c );
			}
			else if ( '\\' == c ) {
				// skip sending the backslash and instead send then next character, treating is as a literal
				recognizer.other( sqlString.charAt( ++indx ) );
			}
			else {
				if ( c == ':' ) {
					// named parameter
					final int right = StringHelper.firstIndexOfChar( sqlString, ParserHelper.HQL_SEPARATORS_BITSET, indx + 1 );
					final int chopLocation = right < 0 ? sqlString.length() : right;
					final String param = sqlString.substring( indx + 1, chopLocation );
					if ( StringHelper.isEmpty( param ) ) {
						throw new QueryException(
								"Space is not allowed after parameter prefix ':' [" + sqlString + "]"
						);
					}
					recognizer.namedParameter( param, indx );
					indx = chopLocation - 1;
				}
				else if ( c == '?' ) {
					// could be either an ordinal or JPA-positional parameter
					if ( indx < stringLength - 1 && Character.isDigit( sqlString.charAt( indx + 1 ) ) ) {
						// a peek ahead showed this as an JPA-positional parameter
						final int right = StringHelper.firstIndexOfChar( sqlString, ParserHelper.HQL_SEPARATORS, indx + 1 );
						final int chopLocation = right < 0 ? sqlString.length() : right;
						final String param = sqlString.substring( indx + 1, chopLocation );
						// make sure this "name" is an integral
						try {
							Integer.valueOf( param );
						}
						catch( NumberFormatException e ) {
							throw new QueryException( "JPA-style positional param was not an integral ordinal" );
						}
						recognizer.jpaPositionalParameter( param, indx );
						indx = chopLocation - 1;
					}
					else {
						if ( hasMainOutputParameter && !foundMainOutputParam ) {
							foundMainOutputParam = true;
							recognizer.outParameter( indx );
						}
						else {
							recognizer.ordinalParameter( indx );
						}
					}
				}
				else {
					recognizer.other( c );
				}
			}
		}
	}

	
Exposed as public solely for use from tests

Params:
  • sqlString – The SQL string to check
Returns:true/false
/**
	 * Exposed as public solely for use from tests
	 *
	 * @param sqlString The SQL string to check
	 *
	 * @return true/false
	 */
	public static boolean startsWithEscapeCallTemplate(String sqlString) {
		if ( ! ( sqlString.startsWith( "{" ) && sqlString.endsWith( "}" ) ) ) {
			return false;
		}

		final int chopLocation = sqlString.indexOf( "call" );
		if ( chopLocation <= 0 ) {
			return false;
		}

		final String checkString = sqlString.substring( 1, chopLocation + 4 );
		final String fixture = "?=call";
		int fixturePosition = 0;
		boolean matches = true;
		final int max = checkString.length();
		for ( int i = 0; i < max; i++ ) {
			final char c = Character.toLowerCase( checkString.charAt( i ) );
			if ( Character.isWhitespace( c ) ) {
				continue;
			}
			if ( c == fixture.charAt( fixturePosition ) ) {
				fixturePosition++;
				continue;
			}
			matches = false;
			break;
		}

		return matches;
	}

}