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 * SciJava Common shared library for SciJava software.
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 * Institute of Molecular Cell Biology and Genetics, University of
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 *    this list of conditions and the following disclaimer.
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 *    this list of conditions and the following disclaimer in the documentation
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package org.scijava.download;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;

import org.scijava.io.handle.AbstractDataHandle;
import org.scijava.io.handle.DataHandle;
import org.scijava.io.location.Location;

/**
 * {@link DataHandle} plugin for writing to multiple {@link DataHandle}s.
 * 
 * @author Curtis Rueden
 */
public class MultiWriteHandle extends AbstractDataHandle {

	private final List> handles;

	public MultiWriteHandle(final DataHandle... handles) {
		this.handles = new ArrayList<>(Arrays.asList(handles));
	}

	// -- DataHandle methods --

	@Override
	public boolean isReadable() {
		return false;
	}

	@Override
	public boolean isWritable() {
		boolean writable = true;
		// NB: Somewhat arbitrarily, we are writable iff all our constituents are.
		for (final DataHandle h : handles)
			writable &= h.isWritable();
		return writable;
	}

	@Override
	public boolean exists() throws IOException {
		boolean exists = true;
		// NB: Somewhat arbitrarily, we exist iff any of our constituents exist.
		for (final DataHandle h : handles)
			exists |= h.isWritable();
		return exists;
	}

	@Override
	public Date lastModified() throws IOException {
		for (final DataHandle h : handles) {
			final Date lastModified = h.lastModified();
			if (lastModified != null) return lastModified;
		}
		return null;
	}

	@Override
	public String checksum() throws IOException {
		for (final DataHandle h : handles) {
			final String checksum = h.checksum();
			if (checksum != null) return checksum;
		}
		return null;
	}

	@Override
	public long offset() throws IOException {
		return handles.get(0).offset();
	}

	@Override
	public void seek(long pos) throws IOException {
		// TODO: parallelStream().forEach() for performance.
		for (final DataHandle h : handles)
			h.seek(pos);
	}

	@Override
	public long length() throws IOException {
		return handles.get(0).length();
	}

	@Override
	public void setLength(long length) throws IOException {
		for (final DataHandle h : handles)
			h.setLength(length);
	}

	@Override
	public int read(byte[] b, int off, int len) throws IOException {
		throw new UnsupportedOperationException();
	}

	@Override
	public Class getType() {
		return null;
	}

	@Override
	public byte readByte() throws IOException {
		throw new UnsupportedOperationException();
	}

	@Override
	public void write(final int b) throws IOException {
		// TODO: parallelStream().forEach() for performance.
		for (final DataHandle h : handles)
			h.write(b);
	}

	@Override
	public void write(byte[] b, int off, int len) throws IOException {
		// TODO: parallelStream().forEach() for performance.
		for (final DataHandle h : handles)
			h.write(b, off, len);
	}

	@Override
	public void close() throws IOException {
		// TODO: parallelStream().forEach() for performance.
		for (final DataHandle h : handles)
			h.close();
	}
}