NamedDataSource.java

package org.simplejavamail.converter.internal.mimemessage;

import javax.activation.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import static org.simplejavamail.internal.util.MiscUtil.valueNullOrEmpty;

/**
 * Allows given datasource to be renamed (from {@link javax.activation.DataHandler} perspective).
 *
 * @author Lukas Kosina
 */
class NamedDataSource implements DataSource {

	/**
	 * Original data source used for attachment.
	 */
	private final DataSource dataSource;

	/**
	 * The new name (optional), which will be applied as email attachment.
	 */
	private final String name;

	/**
	 * Used for wrapping data source in parameter. Method {@link NamedDataSource#getName()} will
	 * not use the original name, but it will use the name in the parameter instead (if provided).
	 *
	 * @param dataSource wrapped data source
	 * @param name       new name of data source
	 */
	public NamedDataSource(final String name, final DataSource dataSource) {
		this.dataSource = dataSource;
		this.name = name;
	}

	/**
	 * @return {@link DataSource#getInputStream()}
	 */
	@Override
	public InputStream getInputStream()
			throws IOException {
		return dataSource.getInputStream();
	}

	/**
	 * @return {@link DataSource#getOutputStream()}
	 */
	@Override
	public OutputStream getOutputStream()
			throws IOException {
		return dataSource.getOutputStream();
	}

	/**
	 * @return {@link DataSource#getContentType()}
	 */
	@Override
	public String getContentType() {
		return dataSource.getContentType();
	}

	/**
	 * {@link #name} if provided, {@link DataSource#getName()} of the original datasource otherwise.
	 *
	 * @return name of data source
	 */
	@Override
	public String getName() {
		return !valueNullOrEmpty(name) ? name : dataSource.getName();
	}
}