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package com.j256.ormlite.stmt.mapped;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.j256.ormlite.db.DatabaseType;
import com.j256.ormlite.field.FieldType;
import com.j256.ormlite.stmt.SelectArg;
import com.j256.ormlite.stmt.QueryBuilder.InternalQueryBuilder;
import com.j256.ormlite.support.JdbcTemplate;
import com.j256.ormlite.table.TableInfo;

/**
 * Mapped statement for querying for an object by its ID.
 * 
 * @author graywatson
 */
public class MappedQueryForId extends BaseMappedQuery {

	private final String label;

	protected MappedQueryForId(TableInfo tableInfo, String statement, List argFieldTypeList,
			List resultFieldTypeList, String label) {
		super(tableInfo, statement, argFieldTypeList, resultFieldTypeList);
		this.label = label;
	}

	/**
	 * Query for an object in the database which matches the obj argument.
	 */
	public T execute(JdbcTemplate template, Object obj) throws SQLException {
		Object[] args = new Object[] { getId(obj) };
		// @SuppressWarnings("unchecked")
		Object result = template.queryForOne(statement, args, new int[] { idField.getJdbcTypeVal() }, this);
		if (result == JdbcTemplate.MORE_THAN_ONE) {
			logger.error("{} using '{}' and {} args, got >1 results", label, statement, args.length);
			logArgs(args);
			throw new SQLException(label + " got more than 1 result: " + statement);
		}
		logger.debug("{} using '{}' and {} args, got 1 result", label, statement, args.length);
		logArgs(args);
		@SuppressWarnings("unchecked")
		T castResult = (T) result;
		postProcessResult(obj, castResult);
		return castResult;
	}

	/**
	 * Return the ID from the object passed to execute.
	 */
	protected ID getId(Object obj) throws SQLException {
		@SuppressWarnings("unchecked")
		ID id = (ID) obj;
		return id;
	}

	/**
	 * Post process the result returned by the execute method.
	 */
	protected void postProcessResult(Object obj, T result) throws SQLException {
		// noop
	}

	public static  MappedQueryForId build(DatabaseType databaseType, TableInfo tableInfo)
			throws SQLException {
		List argFieldTypeList = new ArrayList();
		List resultFieldTypeList = new ArrayList();
		String statement = buildStatement(databaseType, tableInfo, argFieldTypeList, resultFieldTypeList);
		if (statement == null) {
			return null;
		} else {
			return new MappedQueryForId(tableInfo, statement, argFieldTypeList, resultFieldTypeList,
					"query-for-id");
		}
	}

	protected static  String buildStatement(DatabaseType databaseType, TableInfo tableInfo,
			List argFieldTypeList, List resultFieldTypeList) throws SQLException {
		FieldType idField = tableInfo.getIdField();
		if (idField == null) {
			return null;
		}
		InternalQueryBuilder qb = new InternalQueryBuilder(databaseType, tableInfo);
		// this selectArg is ignored here because we pass in the id as a fixed argument
		SelectArg idSelectArg = new SelectArg();
		qb.where().eq(idField.getDbColumnName(), idSelectArg);
		List selectArgList = new ArrayList();
		return qb.buildSelectString(argFieldTypeList, resultFieldTypeList, selectArgList);
	}

	private void logArgs(Object[] args) {
		if (args.length > 0) {
			// need to do the (Object) cast to force args to be a single object
			logger.trace("{} arguments: {}", label, (Object) args);
		}
	}
}