Column.java

/*
Copyright (c) 2013 James Ahlborn

Licensed 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

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package com.healthmarketscience.jackcess;

import java.io.IOException;
import java.sql.SQLException;
import java.util.Map;

import com.healthmarketscience.jackcess.complex.ComplexColumnInfo;
import com.healthmarketscience.jackcess.complex.ComplexValue;
import com.healthmarketscience.jackcess.util.ColumnValidator;

/**
 * Access database column definition.  A {@link Table} has a list of Column
 * instances describing the table schema.
 * <p>
 * A Column instance is not thread-safe (see {@link Database} for more
 * thread-safety details).
 *
 * @author James Ahlborn
 * @usage _general_class_
 */
public interface Column 
{
  /**
   * Meaningless placeholder object for inserting values in an autonumber
   * column.  it is not required that this value be used (any passed in value
   * is ignored), but using this placeholder may make code more obvious.
   * @usage _general_field_
   */
  public static final Object AUTO_NUMBER = "<AUTO_NUMBER>";
  
  /**
   * Meaningless placeholder object for updating rows which indicates that a
   * given column should keep its existing value.
   * @usage _general_field_
   */
  public static final Object KEEP_VALUE = "<KEEP_VALUE>";
  
  /**
   * @usage _general_method_
   */
  public Table getTable();

  /**
   * @usage _general_method_
   */
  public Database getDatabase();

  /**
   * @usage _general_method_
   */
  public String getName();

  /**
   * @usage _advanced_method_
   */
  public boolean isVariableLength();

  /**
   * @usage _general_method_
   */
  public boolean isAutoNumber();

  /**
   * @usage _advanced_method_
   */
  public int getColumnIndex();

  /**
   * @usage _general_method_
   */
  public DataType getType();

  /**
   * @usage _general_method_
   */
  public int getSQLType() throws SQLException;

  /**
   * @usage _general_method_
   */
  public boolean isCompressedUnicode();

  /**
   * @usage _general_method_
   */
  public byte getPrecision();

  /**
   * @usage _general_method_
   */
  public byte getScale();

  /**
   * @usage _general_method_
   */
  public short getLength();

  /**
   * @usage _general_method_
   */
  public short getLengthInUnits();

  /**
   * Whether or not this column is "append only" (its history is tracked by a
   * separate version history column).
   * @usage _general_method_
   */
  public boolean isAppendOnly();

  /**
   * Returns whether or not this is a hyperlink column (only possible for
   * columns of type MEMO).
   * @usage _general_method_
   */
  public boolean isHyperlink();

  /**
   * Returns whether or not this is a calculated column.  Note that jackess
   * <b>won't interpret the calculation expression</b> (but the field can be
   * written directly).
   * @usage _general_method_
   */
  public boolean isCalculated();

  /**
   * Returns extended functionality for "complex" columns.
   * @usage _general_method_
   */
  public ComplexColumnInfo<? extends ComplexValue> getComplexInfo();

  /**
   * @return the properties for this column
   * @usage _general_method_
   */
  public PropertyMap getProperties() throws IOException;
  
  /**
   * Returns the column which tracks the version history for an "append only"
   * column.
   * @usage _intermediate_method_
   */
  public Column getVersionHistoryColumn();

  /**
   * Gets currently configured ColumnValidator (always non-{@code null}).
   * @usage _intermediate_method_
   */
  public ColumnValidator getColumnValidator();
  
  /**
   * Sets a new ColumnValidator.  If {@code null}, resets to the value
   * returned from the Database's ColumnValidatorFactory (if the factory
   * returns {@code null}, then the default is used).  Autonumber columns
   * cannot have a validator instance other than the default.
   * @throws IllegalArgumentException if an attempt is made to set a
   *         non-{@code null} ColumnValidator instance on an autonumber column
   * @usage _intermediate_method_
   */
  public void setColumnValidator(ColumnValidator newValidator);
  
  public Object setRowValue(Object[] rowArray, Object value);
  
  public Object setRowValue(Map<String,Object> rowMap, Object value);
  
  public Object getRowValue(Object[] rowArray);
  
  public Object getRowValue(Map<String,?> rowMap);
}