queryselect.java

一个Java持久层类库

//$Id: QuerySelect.java 6999 2005-06-03 02:04:13Z oneovthafew $
package org.hibernate.sql;

import java.util.HashSet;
import java.util.Iterator;

import org.hibernate.dialect.Dialect;

/**
 * A translated HQL query
 * @author Gavin King
 */
public class QuerySelect {
	private Dialect dialect;
	private JoinFragment joins;
	private StringBuffer select = new StringBuffer();
	private StringBuffer where = new StringBuffer();
	private StringBuffer groupBy = new StringBuffer();
	private StringBuffer orderBy = new StringBuffer();
	private StringBuffer having = new StringBuffer();
	private String comment;
	private boolean distinct=false;

	private static final HashSet DONT_SPACE_TOKENS = new HashSet();
	static {
		//dontSpace.add("'");
		DONT_SPACE_TOKENS.add(".");
		DONT_SPACE_TOKENS.add("+");
		DONT_SPACE_TOKENS.add("-");
		DONT_SPACE_TOKENS.add("/");
		DONT_SPACE_TOKENS.add("*");
		DONT_SPACE_TOKENS.add("<");
		DONT_SPACE_TOKENS.add(">");
		DONT_SPACE_TOKENS.add("=");
		DONT_SPACE_TOKENS.add("#");
		DONT_SPACE_TOKENS.add("~");
		DONT_SPACE_TOKENS.add("|");
		DONT_SPACE_TOKENS.add("&");
		DONT_SPACE_TOKENS.add("<=");
		DONT_SPACE_TOKENS.add(">=");
		DONT_SPACE_TOKENS.add("=>");
		DONT_SPACE_TOKENS.add("=<");
		DONT_SPACE_TOKENS.add("!=");
		DONT_SPACE_TOKENS.add("<>");
		DONT_SPACE_TOKENS.add("!#");
		DONT_SPACE_TOKENS.add("!~");
		DONT_SPACE_TOKENS.add("!<");
		DONT_SPACE_TOKENS.add("!>");
		DONT_SPACE_TOKENS.add("("); //for MySQL
		DONT_SPACE_TOKENS.add(")");
	}

	public QuerySelect(Dialect dialect) {
		this.dialect = dialect;
		joins = new QueryJoinFragment(dialect, false);
	}

	public JoinFragment getJoinFragment() {
		return joins;
	}

	public void addSelectFragmentString(String fragment) {
		if ( fragment.length()>0 && fragment.charAt(0)==',' ) fragment = fragment.substring(1);
		fragment = fragment.trim();
		if ( fragment.length()>0 ) {
			if ( select.length()>0 ) select.append(", ");
			select.append(fragment);
		}
	}

	public void addSelectColumn(String columnName, String alias) {
		addSelectFragmentString(columnName + ' ' + alias);
	}

	public void setDistinct(boolean distinct) {
		this.distinct = distinct;
	}

	public void setWhereTokens(Iterator tokens) {
		//if ( conjunctiveWhere.length()>0 ) conjunctiveWhere.append(" and ");
		appendTokens(where, tokens);
	}

	public void prependWhereConditions(String conditions) {
		if (where.length() > 0) {
			where.insert(0, conditions + " and ");
		}
		else {
			where.append(conditions);
		}
	}

	public void setGroupByTokens(Iterator tokens) {
		//if ( groupBy.length()>0 ) groupBy.append(" and ");
		appendTokens(groupBy, tokens);
	}

	public void setOrderByTokens(Iterator tokens) {
		//if ( orderBy.length()>0 ) orderBy.append(" and ");
		appendTokens(orderBy, tokens);
	}

	public void setHavingTokens(Iterator tokens) {
		//if ( having.length()>0 ) having.append(" and ");
		appendTokens(having, tokens);
	}

	public void addOrderBy(String orderByString) {
		if ( orderBy.length() > 0 ) orderBy.append(", ");
		orderBy.append(orderByString);
	}

	public String toQueryString() {
		StringBuffer buf = new StringBuffer(50);
		if (comment!=null) buf.append("/* ").append(comment).append(" */ ");
		buf.append("select ");
		if (distinct) buf.append("distinct ");
		String from = joins.toFromFragmentString();
		if ( from.startsWith(",") ) {
			from = from.substring(1);
		}
		else if ( from.startsWith(" inner join") ){
			from = from.substring(11);
		}

		buf.append( select.toString() )
			.append(" from")
			.append(from);

		String outerJoinsAfterWhere = joins.toWhereFragmentString().trim();
		String whereConditions = where.toString().trim();
		boolean hasOuterJoinsAfterWhere = outerJoinsAfterWhere.length() > 0;
		boolean hasWhereConditions = whereConditions.length() > 0;
		if (hasOuterJoinsAfterWhere || hasWhereConditions) {
			buf.append(" where ");
			if (hasOuterJoinsAfterWhere) {
				buf.append( outerJoinsAfterWhere.substring(4) );
			}
			if (hasWhereConditions) {
				if (hasOuterJoinsAfterWhere) {
					buf.append(" and (");
				}
				buf.append(whereConditions);
				if (hasOuterJoinsAfterWhere) {
					buf.append(")");
				}
			}
		}

		if ( groupBy.length() > 0 ) buf.append(" group by ").append( groupBy.toString() );
		if ( having.length() > 0 ) buf.append(" having ").append( having.toString() );
		if ( orderBy.length() > 0 ) buf.append(" order by ").append( orderBy.toString() );

		return dialect.transformSelectString( buf.toString() );
	}

	private static void appendTokens(StringBuffer buf, Iterator iter) {
		boolean lastSpaceable=true;
		boolean lastQuoted=false;
		while ( iter.hasNext() ) {
			String token = (String) iter.next();
			boolean spaceable = !DONT_SPACE_TOKENS.contains(token);
			boolean quoted = token.startsWith("'");
			if (spaceable && lastSpaceable) {
				if ( !quoted || !lastQuoted ) buf.append(' ');
			}
			lastSpaceable = spaceable;
			buf.append(token);
			lastQuoted = token.endsWith("'");
		}
	}

	public void setComment(String comment) {
		this.comment = comment;
	}

	public QuerySelect copy() {
		QuerySelect copy = new QuerySelect(dialect);
		copy.joins = this.joins.copy();
		copy.select.append( this.select.toString() );
		copy.where.append( this.where.toString() );
		copy.groupBy.append( this.groupBy.toString() );
		copy.orderBy.append( this.orderBy.toString() );
		copy.having.append( this.having.toString() );
		copy.comment = this.comment;
		copy.distinct = this.distinct;
		return copy;
	}

}