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Cayenne Object Persistence Framework
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 *   Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
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 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
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package org.apache.cayenne.access;

import java.sql.Connection;
import java.sql.PreparedStatement;

import org.apache.log4j.Level;
import org.apache.cayenne.dba.DbAdapter;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.EntityInheritanceTree;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.query.Query;

/**
 * Defines API for translation Cayenne queries to JDBC PreparedStatements.
 * 
 * For more information see Cayenne User Guide.  
 * 
 * 
 * @author Andrei Adamchik
 */
public abstract class QueryTranslator {

    /** Query being translated. */
    protected Query query;

    /**
     * JDBC database connection needed to create PreparedStatement. Prior to 1.2 this
     * property was called "con".
     */
    protected Connection connection;

    /**
     * Used mainly for name resolution.
     * 
     * @deprecated Since 1.2 entityResolver property is used.
     */
    protected QueryEngine engine;

    /** Adapter helping to do SQL literal conversions, etc. */
    protected DbAdapter adapter;

    /**
     * Provides access to Cayenne mapping info.
     * 
     * @since 1.2
     */
    protected EntityResolver entityResolver;

    /**
     * Creates PreparedStatement. logLevel parameter is supplied to allow
     * control of logging of produced SQL.
     */
    public abstract PreparedStatement createStatement() throws Exception;

    /**
     * @deprecated since 1.2
     */
    public final PreparedStatement createStatement(Level logLevel) throws Exception {
        return createStatement();
    }

    /** Returns query object being processed. */
    public Query getQuery() {
        return query;
    }

    public void setQuery(Query query) {
        this.query = query;
    }

    /**
     * Returns Connection object used by this translator.
     * 
     * @since 1.2
     */
    public Connection getConnection() {
        return connection;
    }

    /**
     * @since 1.2
     */
    public void setConnection(Connection connection) {
        this.connection = connection;
    }

    /**
     * @deprecated Since 1.2 use getConnection().
     */
    public Connection getCon() {
        return getConnection();
    }

    /**
     * @deprecated since 1.2 use setConnection().
     */
    public void setCon(Connection con) {
        setConnection(con);
    }

    /**
     * Returns QueryEngine used by this translator.
     * 
     * @deprecated Since 1.2 use "getEntityResolver()"
     */
    public QueryEngine getEngine() {
        return engine;
    }

    /**
     * @deprecated Since 1.2 use "setEntityResolver()"
     */
    public void setEngine(QueryEngine engine) {
        this.engine = engine;
    }

    public DbAdapter getAdapter() {
        return adapter;
    }

    public void setAdapter(DbAdapter adapter) {
        this.adapter = adapter;
    }

    /**
     * Returns an EntityInheritanceTree for the root entity.
     * 
     * @since 1.1
     */
    public EntityInheritanceTree getRootInheritanceTree() {
        return getEntityResolver().lookupInheritanceTree(getRootEntity());
    }

    public ObjEntity getRootEntity() {
        return query.getMetaData(getEntityResolver()).getObjEntity();
    }

    public DbEntity getRootDbEntity() {
        return query.getMetaData(getEntityResolver()).getDbEntity();
    }

    /**
     * @since 1.2
     */
    public EntityResolver getEntityResolver() {
        return entityResolver;
    }

    /**
     * @since 1.2
     */
    public void setEntityResolver(EntityResolver entityResolver) {
        this.entityResolver = entityResolver;
    }
}