/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, 2013, Red Hat Inc. 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 Inc.
 *
 * 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 org.hibernate.AssertionFailure;

An ANSI-style join.
Author:
Gavin King/**
 * An ANSI-style join.
 *
 * @author Gavin King
 */
public class ANSIJoinFragment extends JoinFragment {
	private StringBuilder buffer = new StringBuilder();
	private StringBuilder conditions = new StringBuilder();

	
Adds a join, represented by the given information, to the fragment.
Params:
tableName – The name of the table being joined.
alias – The alias applied to the table being joined.
fkColumns – The columns (from the table being joined) used to define the join-restriction (the ON)
pkColumns – The columns (from the table being joined to) used to define the join-restriction (the ON)
joinType – The type of join to produce (INNER, etc)./**
	 * Adds a join, represented by the given information, to the fragment.
	 *
	 * @param tableName The name of the table being joined.
	 * @param alias The alias applied to the table being joined.
	 * @param fkColumns The columns (from the table being joined) used to define the join-restriction (the ON)
	 * @param pkColumns The columns (from the table being joined to) used to define the join-restriction (the ON)
	 * @param joinType The type of join to produce (INNER, etc).
	 */
	public void addJoin(String tableName, String alias, String[] fkColumns, String[] pkColumns, JoinType joinType) {
		addJoin( tableName, alias, fkColumns, pkColumns, joinType, null );
	}

	
Adds a join, represented by the given information, to the fragment.
Params:
rhsTableName – The name of the table being joined (the RHS table).
rhsAlias – The alias applied to the table being joined (the alias for the RHS table).
lhsColumns – The columns (from the table being joined) used to define the join-restriction (the ON).  These
are the LHS columns, and are expected to be qualified.
rhsColumns – The columns (from the table being joined to) used to define the join-restriction (the ON).  These
are the RHS columns and are expected to *not* be qualified.
joinType – The type of join to produce (INNER, etc).
on – Any extra join restrictions/**
	 * Adds a join, represented by the given information, to the fragment.
	 *
	 * @param rhsTableName The name of the table being joined (the RHS table).
	 * @param rhsAlias The alias applied to the table being joined (the alias for the RHS table).
	 * @param lhsColumns The columns (from the table being joined) used to define the join-restriction (the ON).  These
	 * are the LHS columns, and are expected to be qualified.
	 * @param rhsColumns The columns (from the table being joined to) used to define the join-restriction (the ON).  These
	 * are the RHS columns and are expected to *not* be qualified.
	 * @param joinType The type of join to produce (INNER, etc).
	 * @param on Any extra join restrictions
	 */
	public void addJoin(
			String rhsTableName,
			String rhsAlias,
			String[] lhsColumns,
			String[] rhsColumns,
			JoinType joinType,
			String on) {
		final String joinString;
		switch (joinType) {
			case INNER_JOIN:
				joinString = " inner join ";
				break;
			case LEFT_OUTER_JOIN:
				joinString = " left outer join ";
				break;
			case RIGHT_OUTER_JOIN:
				joinString = " right outer join ";
				break;
			case FULL_JOIN:
				joinString = " full outer join ";
				break;
			default:
				throw new AssertionFailure("undefined join type");
		}

		this.buffer.append(joinString)
			.append(rhsTableName)
			.append(' ')
			.append(rhsAlias)
			.append(" on ");


		for ( int j=0; j<lhsColumns.length; j++) {
			this.buffer.append( lhsColumns[j] )
				.append('=')
				.append(rhsAlias)
				.append('.')
				.append( rhsColumns[j] );
			if ( j < lhsColumns.length-1 ) {
				this.buffer.append( " and " );
			}
		}

		addCondition( buffer, on );

	}

	@Override
	public String toFromFragmentString() {
		return this.buffer.toString();
	}

	@Override
	public String toWhereFragmentString() {
		return this.conditions.toString();
	}

	@Override
	public void addJoins(String fromFragment, String whereFragment) {
		this.buffer.append( fromFragment );
		//where fragment must be empty!
	}

	@Override
	public JoinFragment copy() {
		final ANSIJoinFragment copy = new ANSIJoinFragment();
		copy.buffer = new StringBuilder( this.buffer.toString() );
		return copy;
	}

	
Adds a condition to the join fragment. For each given column a predicate is built in the form: [alias.[column] = [condition] 
Params:
alias – The alias to apply to column(s)
columns – The columns to apply restriction
condition – The restriction condition/**
	 * Adds a condition to the join fragment.  For each given column a predicate is built in the form:
	 * {@code [alias.[column] = [condition]}
	 *
	 * @param alias The alias to apply to column(s)
	 * @param columns The columns to apply restriction
	 * @param condition The restriction condition
	 */
	public void addCondition(String alias, String[] columns, String condition) {
		for ( String column : columns ) {
			this.conditions.append( " and " )
					.append( alias )
					.append( '.' )
					.append( column )
					.append( condition );
		}
	}

	@Override
	public void addCrossJoin(String tableName, String alias) {
		this.buffer.append(", ")
			.append(tableName)
			.append(' ')
			.append(alias);
	}

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

	}

	@Override
	public boolean addCondition(String condition) {
		return addCondition(conditions, condition);
	}

	
Adds an externally built join fragment.
Params:
fromFragmentString – The join fragment string/**
	 * Adds an externally built join fragment.
	 *
	 * @param fromFragmentString The join fragment string
	 */
	public void addFromFragmentString(String fromFragmentString) {
		this.buffer.append(fromFragmentString);
	}

}