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package org.scijava.io.handle;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Date;

import org.scijava.io.location.FileLocation;
import org.scijava.plugin.Plugin;

/**
 * {@link DataHandle} for a {@link FileLocation}.
 * 
 * @author Curtis Rueden
 */
@Plugin(type = DataHandle.class)
public class FileHandle extends AbstractDataHandle {

	// -- Fields --

	/** The {@link RandomAccessFile} backing this file handle. */
	private RandomAccessFile raf;

	/** The mode of the {@link RandomAccessFile}. */
	private String mode = "rw";

	/** True iff the {@link #close()} has already been called. */
	private boolean closed;

	// -- FileHandle methods --

	/** Gets the random access file object backing this FileHandle. */
	public RandomAccessFile getRandomAccessFile() throws IOException {
		return raf();
	}

	public String getMode() {
		return mode;
	}

	public void setMode(final String mode) {
		if (raf != null) {
			throw new IllegalStateException("File already initialized");
		}
		this.mode = mode;
	}

	// -- DataHandle methods --

	@Override
	public boolean isReadable() {
		return getMode().contains("r");
	}

	@Override
	public boolean isWritable() {
		return getMode().contains("w");
	}

	@Override
	public boolean exists() {
		return get().getFile().exists();
	}

	@Override
	public Date lastModified() {
		final long lastModified = get().getFile().lastModified();
		return lastModified == 0 ? null : new Date(lastModified);
	}

	@Override
	public long offset() throws IOException {
		return raf().getFilePointer();
	}

	@Override
	public long length() throws IOException {
		return exists() ? raf().length() : -1;
	}

	@Override
	public void setLength(final long length) throws IOException {
		raf().setLength(length);
	}

	@Override
	public int read() throws IOException {
		return raf().read();
	}

	@Override
	public int read(final byte[] b) throws IOException {
		return raf().read(b);
	}

	@Override
	public int read(final byte[] b, final int off, final int len)
		throws IOException
	{
		return raf().read(b, off, len);
	}

	@Override
	public void seek(final long pos) throws IOException {
		raf().seek(pos);
	}

	// -- DataInput methods --

	@Override
	public boolean readBoolean() throws IOException {
		return raf().readBoolean();
	}

	@Override
	public byte readByte() throws IOException {
		return raf().readByte();
	}

	@Override
	public char readChar() throws IOException {
		return raf().readChar();
	}

	@Override
	public double readDouble() throws IOException {
		return raf().readDouble();
	}

	@Override
	public float readFloat() throws IOException {
		return raf().readFloat();
	}

	@Override
	public void readFully(final byte[] b) throws IOException {
		raf().readFully(b);
	}

	@Override
	public void readFully(final byte[] b, final int off, final int len)
		throws IOException
	{
		raf().readFully(b, off, len);
	}

	@Override
	public int readInt() throws IOException {
		return raf().readInt();
	}

	@Override
	public String readLine() throws IOException {
		return raf().readLine();
	}

	@Override
	public long readLong() throws IOException {
		return raf().readLong();
	}

	@Override
	public short readShort() throws IOException {
		return raf().readShort();
	}

	@Override
	public int readUnsignedByte() throws IOException {
		return raf().readUnsignedByte();
	}

	@Override
	public int readUnsignedShort() throws IOException {
		return raf().readUnsignedShort();
	}

	@Override
	public String readUTF() throws IOException {
		return raf().readUTF();
	}

	@Override
	public int skipBytes(final int n) throws IOException {
		return raf().skipBytes(n);
	}

	// -- DataOutput methods --

	@Override
	public void write(final byte[] b) throws IOException {
		raf().write(b);
	}

	@Override
	public void write(final byte[] b, final int off, final int len)
		throws IOException
	{
		raf().write(b, off, len);
	}

	@Override
	public void write(final int b) throws IOException {
		raf().write(b);
	}

	@Override
	public void writeBoolean(final boolean v) throws IOException {
		raf().writeBoolean(v);
	}

	@Override
	public void writeByte(final int v) throws IOException {
		raf().writeByte(v);
	}

	@Override
	public void writeBytes(final String s) throws IOException {
		raf().writeBytes(s);
	}

	@Override
	public void writeChar(final int v) throws IOException {
		raf().writeChar(v);
	}

	@Override
	public void writeChars(final String s) throws IOException {
		raf().writeChars(s);
	}

	@Override
	public void writeDouble(final double v) throws IOException {
		raf().writeDouble(v);
	}

	@Override
	public void writeFloat(final float v) throws IOException {
		raf().writeFloat(v);
	}

	@Override
	public void writeInt(final int v) throws IOException {
		raf().writeInt(v);
	}

	@Override
	public void writeLong(final long v) throws IOException {
		raf().writeLong(v);
	}

	@Override
	public void writeShort(final int v) throws IOException {
		raf().writeShort(v);
	}

	@Override
	public void writeUTF(final String str) throws IOException {
		raf().writeUTF(str);
	}

	// -- Closeable methods --

	@Override
	public synchronized void close() throws IOException {
		if (raf != null) raf().close();
		closed = true;
	}

	// -- Typed methods --

	@Override
	public Class getType() {
		return FileLocation.class;
	}

	// -- Helper methods --

	private RandomAccessFile raf() throws IOException {
		if (raf == null) initRAF();
		return raf;
	}

	private synchronized void initRAF() throws IOException {
		if (closed) throw new IOException("Handle already closed");
		if (raf != null) return;
		raf = new RandomAccessFile(get().getFile(), getMode());
	}
}