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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * JBoss, Home of Professional Open Source
 *
 * Copyright 2013 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.xnio.conduits;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import org.xnio.channels.StreamSinkChannel;

/**
 * A stream source conduit which limits the length of input.
 *
 * @author David M. Lloyd
 */
public final class FixedLengthStreamSourceConduit extends AbstractStreamSourceConduit implements StreamSourceConduit {
    private long remaining;

    /**
     * Construct a new instance.
     *
     * @param next the conduit to limit
     * @param remaining the number of bytes to limit to
     */
    public FixedLengthStreamSourceConduit(final StreamSourceConduit next, final long remaining) {
        super(next);
        this.remaining = remaining;
    }

    public long transferTo(final long position, final long count, final FileChannel target) throws IOException {
        long length = this.remaining;
        if (length > 0) {
            final long res = next.transferTo(position, Math.min(count, length), target);
            if (res > 0L) {
                this.remaining = length - res;
            }
            return res;
        } else {
            return 0;
        }
    }

    public long transferTo(final long count, final ByteBuffer throughBuffer, final StreamSinkChannel target) throws IOException {
        long length = this.remaining;
        if (length > 0) {
            final long res = next.transferTo(Math.min(count, length), throughBuffer, target);
            if (res > 0L) {
                this.remaining = length - res;
            }
            return res;
        } else {
            return -1L;
        }
    }

    public int read(final ByteBuffer dst) throws IOException {
        final int limit = dst.limit();
        final int pos = dst.position();
        final int res;
        final long length = this.remaining;
        if (length == 0L) {
            return -1;
        }
        if (limit - pos > length) {
            dst.limit(pos + (int) length);
            try {
                res = next.read(dst);
            } finally {
                dst.limit(limit);
            }
        } else {
            res = next.read(dst);
        }
        if (res > 0L) {
            this.remaining = length - res;
        }
        return res;
    }

    public long read(final ByteBuffer[] dsts, final int offs, final int len) throws IOException {
        if (len == 0) {
            return 0L;
        } else if (len == 1) {
            return read(dsts[offs]);
        }
        final long length = this.remaining;
        if (length == 0L) {
            return -1L;
        }
        long res;
        int lim;
        // The total amount of buffer space discovered so far.
        long t = 0L;
        for (int i = 0; i < length; i ++) {
            final ByteBuffer buffer = dsts[i + offs];
            // Grow the discovered buffer space by the remaining size of the current buffer.
            // We want to capture the limit so we calculate "remaining" ourselves.
            t += (lim = buffer.limit()) - buffer.position();
            if (t > length) {
                // only read up to this point, and trim the last buffer by the number of extra bytes
                buffer.limit(lim - (int) (t - length));
                try {
                    res = next.read(dsts, offs, i + 1);
                    if (res > 0L) {
                        this.remaining = length - res;
                    }
                    return res;
                } finally {
                    // restore the original limit
                    buffer.limit(lim);
                }
            }
        }
        // the total buffer space is less than the remaining count.
        res = t == 0L ? 0L : next.read(dsts, offs, len);
        if (res > 0L) {
            this.remaining = length - res;
        }
        return res;
    }

    /**
     * Get the number of bytes which remain available to read.
     *
     * @return the number of bytes which remain available to read
     */
    public long getRemaining() {
        return remaining;
    }
}