juneau-rest/juneau-rest-server/src/main/java/org/apache/juneau/rest/util/FinishablePrintWriter.java

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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.rest.util;

import java.io.*;

import org.apache.juneau.encoders.*;

/**
 * A wrapped {@link PrintWriter} with an added <c>finish()</c> method.
 */
public class FinishablePrintWriter extends PrintWriter implements Finishable {

	final Finishable f;

	/**
	 * Constructor.
	 *
	 * @param out The wrapped output stream.
	 * @param characterEncoding The character encoding of the output stream.
	 * @param autoFlush Automatically flush after every println.
	 * @throws IOException Thrown by underlying stream.
	 */
	public FinishablePrintWriter(OutputStream out, String characterEncoding, boolean autoFlush) throws IOException {
		super(new OutputStreamWriter(out, characterEncoding), autoFlush);
		f = (out instanceof Finishable ? (Finishable)out : null);
	}

	/**
	 * Calls {@link Finishable#finish()} on the underlying output stream.
	 *
	 * <p>
	 * A no-op if the underlying output stream does not implement the {@link Finishable} interface.
	 */
	@Override /* Finishable */
	public void finish() throws IOException {
		if (f != null)
			f.finish();
	}
}