org.eobjects.analyzer.beans.api.OutputColumns Maven / Gradle / Ivy
/**
* eobjects.org AnalyzerBeans
* Copyright (C) 2010 eobjects.org
*
* 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.eobjects.analyzer.beans.api;
import java.io.Serializable;
import java.util.Arrays;
/**
* Represents the output columns yielded by a Transformer given a certain
* configuration.
*
* By default the output columns of a transformer will have the type specified
* by the generic argument (E) in {@link Transformer}. The column type can
* however be overridden using the output columns, by setting specific column
* types per column index using the {@link #setColumnType(int, Class)} method.
*/
public final class OutputColumns implements Serializable {
private static final long serialVersionUID = 1L;
/**
* Factory/convenience method for retrieving a single output column
* instance.
*
* @return a single output column instance.
*/
public static OutputColumns singleOutputColumn() {
return new OutputColumns(1);
}
private final String[] columnNames;
private final Class[] columnTypes;
/**
* Constructs an OutputColumns object with a variable amount of anonymous
* columns.
*
* @param columns
* the amount of columns.
*/
public OutputColumns(int columns) {
if (columns < 1) {
throw new IllegalArgumentException("columns must be 1 or higher");
}
columnNames = new String[columns];
columnTypes = new Class[columns];
}
/**
* Constructs an OutputColumns object with named columns.
*
* @param columnNames
* the names of the output columns.
*/
public OutputColumns(String[] columnNames) {
this(columnNames, null);
}
/**
* Constructs an OutputColumns object with named columns.
*
* @param firstColumnName
* the first column name
* @param additionalColumnNames
* the additional column names (varargs)
*/
public OutputColumns(String firstColumnName, String... additionalColumnNames) {
int length = additionalColumnNames.length + 1;
columnNames = new String[length];
columnNames[0] = firstColumnName;
for (int i = 0; i < additionalColumnNames.length; i++) {
columnNames[i + 1] = additionalColumnNames[i];
}
columnTypes = new Class[length];
}
/**
* Constructs an OutputColumns object with named columns.
*
* @param columnNames
* the names of the output columns.
* @param columnTypes
* the types of the output columns.
*/
public OutputColumns(String[] columnNames, Class[] columnTypes) {
if (columnNames == null) {
throw new IllegalArgumentException("Arguments cannot be null");
}
if (columnNames.length < 1) {
throw new IllegalArgumentException("Column names length must be 1 or greater");
}
if (columnTypes == null) {
columnTypes = new Class[columnNames.length];
}
if (columnNames.length != columnTypes.length) {
throw new IllegalArgumentException("Column names and column types must have equal length");
}
this.columnNames = columnNames.clone();
this.columnTypes = columnTypes.clone();
}
/**
* Gets the column type (if specified) by index
*
* @param index
* the index of the column
* @return the type (if specified) of the column
*/
public Class getColumnType(int index) {
return columnTypes[index];
}
/**
* Sets the type of a column.
*
* @param index
* the index of a column
* @param type
* the column type
*/
public void setColumnType(int index, Class type) {
columnTypes[index] = type;
}
/**
* Gets the column name of a column by index
*
* @param index
* the index of the column
* @return the name of the column
*/
public String getColumnName(int index) {
return columnNames[index];
}
/**
* Sets the name of a column.
*
* @param index
* the index of a column
* @param name
* the column name
*/
public void setColumnName(int index, String name) {
columnNames[index] = name;
}
/**
* Gets the amount of columns in this OutputColumns object
*
* @return an integer representing the amount of columns available
*/
public int getColumnCount() {
return columnNames.length;
}
@Override
public String toString() {
return "OutputColumns" + Arrays.toString(columnNames);
}
}