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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.sql;
import java.util.HashSet;
import java.util.Set;

/**
 * An Oracle-style (theta) join
 *
 * @author Jon Lipsky, Gavin King
 */
public class OracleJoinFragment extends JoinFragment {

	private StringBuilder afterFrom = new StringBuilder();
	private StringBuilder afterWhere = new StringBuilder();

	public void addJoin(String tableName, String alias, String[] fkColumns, String[] pkColumns, JoinType joinType) {

		addCrossJoin( tableName, alias );

		for ( int j = 0; j < fkColumns.length; j++ ) {
			setHasThetaJoins( true );
			afterWhere.append( " and " )
					.append( fkColumns[j] );
			if ( joinType == JoinType.RIGHT_OUTER_JOIN || joinType == JoinType.FULL_JOIN ) afterWhere.append( "(+)" );
			afterWhere.append( '=' )
					.append( alias )
					.append( '.' )
					.append( pkColumns[j] );
			if ( joinType == JoinType.LEFT_OUTER_JOIN || joinType == JoinType.FULL_JOIN ) afterWhere.append( "(+)" );
		}

	}

	public String toFromFragmentString() {
		return afterFrom.toString();
	}

	public String toWhereFragmentString() {
		return afterWhere.toString();
	}

	public void addJoins(String fromFragment, String whereFragment) {
		afterFrom.append( fromFragment );
		afterWhere.append( whereFragment );
	}

	public JoinFragment copy() {
		OracleJoinFragment copy = new OracleJoinFragment();
		copy.afterFrom = new StringBuilder( afterFrom.toString() );
		copy.afterWhere = new StringBuilder( afterWhere.toString() );
		return copy;
	}

	public void addCondition(String alias, String[] columns, String condition) {
		for ( int i = 0; i < columns.length; i++ ) {
			afterWhere.append( " and " )
					.append( alias )
					.append( '.' )
					.append( columns[i] )
					.append( condition );
		}
	}

	public void addCrossJoin(String tableName, String alias) {
		afterFrom.append( ", " )
				.append( tableName )
				.append( ' ' )
				.append( alias );
	}

	public void addCondition(String alias, String[] fkColumns, String[] pkColumns) {
		throw new UnsupportedOperationException();
	}

	public boolean addCondition(String condition) {
		return addCondition( afterWhere, condition );
	}

	public void addFromFragmentString(String fromFragmentString) {
		afterFrom.append( fromFragmentString );
	}

	public void addJoin(String tableName, String alias, String[] fkColumns, String[] pkColumns, JoinType joinType, String on) {
		//arbitrary on clause ignored!!
		addJoin( tableName, alias, fkColumns, pkColumns, joinType );
		if ( joinType == JoinType.INNER_JOIN ) {
			addCondition( on );
		}
		else if ( joinType == JoinType.LEFT_OUTER_JOIN ) {
			addLeftOuterJoinCondition( on );
		}
		else {
			throw new UnsupportedOperationException( "join type not supported by OracleJoinFragment (use Oracle9iDialect/Oracle10gDialect)" );
		}
	}

	/**
	 * This method is a bit of a hack, and assumes
	 * that the column on the "right" side of the
	 * join appears on the "left" side of the
	 * operator, which is extremely wierd if this
	 * was a normal join condition, but is natural
	 * for a filter.
	 */
	private void addLeftOuterJoinCondition(String on) {
		StringBuilder buf = new StringBuilder( on );
		for ( int i = 0; i < buf.length(); i++ ) {
			char character = buf.charAt( i );
			final boolean isInsertPoint = OPERATORS.contains( Character.valueOf( character ) )
					|| ( character == ' ' && buf.length() > i + 3 && "is ".equals( buf.substring( i + 1, i + 4 ) ) );
			if ( isInsertPoint ) {
				buf.insert( i, "(+)" );
				i += 3;
			}
		}
		addCondition( buf.toString() );
	}

	private static final Set OPERATORS = new HashSet();

	static {
		OPERATORS.add( Character.valueOf( '=' ) );
		OPERATORS.add( Character.valueOf( '<' ) );
		OPERATORS.add( Character.valueOf( '>' ) );
	}
}