org.tentackle.sql.metadata.ColumnMetaData Maven / Gradle / Ivy
/*
* Tentackle - http://www.tentackle.org.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.tentackle.sql.metadata;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Objects;
import org.tentackle.common.BasicStringHelper;
import org.tentackle.sql.Backend;
import org.tentackle.sql.SqlType;
/**
* Meta data for a column
*
* @author harald
*/
public class ColumnMetaData {
// properties the backend may not support
private static final String SUPPORTS_AUTOINCREMENT = "supportsAutoIncrement";
private static final String SUPPORTS_GENERATED = "supportsGenerated";
private final TableMetaData tableMetaData; // the table this column belongs to
private String columnName; // the column columnName
private String comment; // the comment
private int type; // the type code from java.sql.Types
private String typeName; // backend-specific type columnName
private int size; // the size / length (for ex. in VARCHAR)
private int scale; // the scale (for ex. DECIMAL)
private String defaultValue; // column default, null = none
private boolean nullable; // true if column may contain nulls
private boolean generated; // true if column is generated by the backend
private boolean autoIncrement; // true if column is autoincremented by the backend
/**
* Creates column meta data.
*
* @param tableMetaData the table meta data this column belongs to
*/
public ColumnMetaData(TableMetaData tableMetaData) {
this.tableMetaData = tableMetaData;
}
/**
* Gets the table meta data.
*
* @return the table this column belongs to
*/
public TableMetaData getTableMetaData() {
return tableMetaData;
}
/**
* Sets up the column from the database meta data result.
*
* @param resultSet the column result set
* @throws SQLException the processing the result set failed
*/
public void setupColumnFromMetaData(ResultSet resultSet) throws SQLException {
columnName = BasicStringHelper.toLower(resultSet.getString("COLUMN_NAME"));
comment = resultSet.getString("REMARKS");
size = resultSet.getInt("COLUMN_SIZE");
scale = resultSet.getShort("DECIMAL_DIGITS");
nullable = resultSet.getInt("NULLABLE") == DatabaseMetaData.columnNullable;
type = resultSet.getInt("DATA_TYPE");
typeName = resultSet.getString("TYPE_NAME");
defaultValue = resultSet.getString("COLUMN_DEF");
// optional features
if (isSupported(SUPPORTS_GENERATED)) {
try {
autoIncrement = Objects.equals("YES", resultSet.getString("IS_AUTOINCREMENT"));
}
catch (SQLException sqx) {
setSupported(SUPPORTS_GENERATED, false);
}
}
if (isSupported(SUPPORTS_GENERATED)) {
try {
generated = Objects.equals("YES", resultSet.getString("IS_GENERATEDCOLUMN"));
}
catch (SQLException sqx) {
setSupported(SUPPORTS_GENERATED, false);
}
}
validate();
}
/**
* Gets the columnName of the column.
*
* @return the columnName (always in lowercase)
*/
public String getColumnName() {
return columnName;
}
/**
* Sets the column name.
*
* @param columnName the column name
*/
public void setColumnName(String columnName) {
this.columnName = columnName;
}
/**
* Gets the comment.
*
* @return the comment, null if none
*/
public String getComment() {
return comment;
}
/**
* Sets the comment.
*
* @param comment the comment
*/
public void setComment(String comment) {
this.comment = comment;
}
/**
* Gets the column's type.
*
* @return the type
* @see java.sql.Types
*/
public int getType() {
return type;
}
/**
* Sets the type.
*
* @param type the type
*/
public void setType(int type) {
this.type = type;
}
/**
* Gets the backend-specific type columnName.
*
* @return the type columnName
*/
public String getTypeName() {
return typeName;
}
/**
* Sets the type name.
*
* @param typeName the type name
*/
public void setTypeName(String typeName) {
this.typeName = typeName;
}
/**
* Gets the column's size.
*
* @return the size
*/
public int getSize() {
return size;
}
/**
* Sets the size.
*
* @param size the size
*/
public void setSize(int size) {
this.size = size;
}
/**
* Gets the numeric scale.
*
* @return the scale
*/
public int getScale() {
return scale;
}
/**
* Sets the scale.
*
* @param scale the scale
*/
public void setScale(int scale) {
this.scale = scale;
}
/**
* Gets the column's default.
*
* @return the default value
*/
public String getDefaultValue() {
return defaultValue;
}
/**
* Sets the default value.
*
* @param defaultValue the default value
*/
public void setDefaultValue(String defaultValue) {
this.defaultValue = defaultValue;
}
/**
* Returns whether column is nullable.
*
* @return true if nullable
*/
public boolean isNullable() {
return nullable;
}
/**
* Sets whether column is nullable.
*
* @param nullable true if nullable
*/
public void setNullable(boolean nullable) {
this.nullable = nullable;
}
/**
* Returns whether column is generated by the backend.
*
* @return true if generated
*/
public boolean isGenerated() {
return generated;
}
/**
* Sets whether column is generated by the backend.
*
* @param generated if generated
*/
public void setGenerated(boolean generated) {
this.generated = generated;
}
/**
* Returns whether column is auto-incremented by the backend.
*
* @return true if autoincremented
*/
public boolean isAutoIncrement() {
return autoIncrement;
}
/**
* Sets whether column is auto-incremented by the backend.
*
* @param autoIncrement true if autoincremented
*/
public void setAutoIncrement(boolean autoIncrement) {
this.autoIncrement = autoIncrement;
}
/**
* Checks whether colunm's type matches given SqlType according to the backend.
*
* @param sqlType the sqltype
* @return true if matches
*/
public boolean matchesSqlType(SqlType sqlType) {
Backend backend = tableMetaData.getModelMetaData().getBackend();
SqlType[] possibleSqlTypes = backend.jdbcTypeToSqlType(type, size, scale);
for (SqlType possibleType: possibleSqlTypes) {
if (sqlType == possibleType) {
return true;
}
}
return false;
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder(columnName);
buf.append(" ");
buf.append(MetaDataHelper.jdbcTypeToString(type));
if (size > 0) {
buf.append("(");
buf.append(size);
if (scale > 0) {
buf.append(",");
buf.append(scale);
}
buf.append(")");
}
if (!nullable) {
buf.append(" NOT NULL");
}
if (defaultValue != null) {
buf.append(" DEFAULT ");
buf.append(defaultValue);
}
if (autoIncrement) {
buf.append(" AUTOINCREMENT");
}
buf.append(" -- ");
buf.append(typeName);
if (generated) {
buf.append(", GENERATED");
}
return buf.toString();
}
/**
* Validates and postprocesses the column data.
*/
public void validate() {
if (comment != null && comment.isEmpty()) {
comment = null;
}
if (defaultValue != null && defaultValue.isEmpty()) {
defaultValue = null;
}
}
/**
* Returns whether a feature is supported by the backend.
*
* @param property the feature
* @return true if supported or not known whether supported or not, false if known to be not supported
*/
private boolean isSupported(String property) {
String val = tableMetaData.getModelMetaData().getProperties().getProperty(property);
return val == null ? true : Boolean.valueOf(val);
}
/**
* Sets whether a feature is supported by the backend.
* @param property the feature
* @param supported true if supported, false if not supported
*/
private void setSupported(String property, boolean supported) {
tableMetaData.getModelMetaData().getProperties().setProperty(property, Boolean.toString(supported));
}
}
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