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5 ebruchez 1 
/**
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 *  Copyright (C) 2004 Orbeon, Inc.
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 *
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 *  This program is free software; you can redistribute it and/or modify it under the terms of the
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 *  GNU Lesser General Public License as published by the Free Software Foundation; either version
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 *  2.1 of the License, or (at your option) any later version.
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 *
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 *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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 *  See the GNU Lesser General Public License for more details.
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 *
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 *  The full text of the license is available at http://www.gnu.org/copyleft/lesser.html
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 */
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package org.orbeon.oxf.util;
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import org.orbeon.oxf.common.OXFException;
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import java.io.IOException;
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import java.io.Reader;
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import java.util.Iterator;
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public class SequenceReader extends Reader {
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    private Iterator iterator;
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    private Reader reader;
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    public SequenceReader(Iterator iterator) {
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        this.iterator = iterator;
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        try {
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            nextReader();
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        } catch (IOException ex) {
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            throw new OXFException("Invalid state");
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        }
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    }
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    public int read() throws IOException {
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        if (reader == null)
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            return -1;
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        int c = reader.read();
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        if (c == -1) {
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            nextReader();
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            return read();
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        }
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        return c;
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    }
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    public int read(char b[], int off, int len) throws IOException {
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        if (reader == null) {
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            return -1;
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        } else if (b == null) {
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            throw new NullPointerException();
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        } else if ((off < 0) || (off > b.length) || (len < 0) ||
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                ((off + len) > b.length) || ((off + len) < 0)) {
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            throw new IndexOutOfBoundsException();
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        } else if (len == 0) {
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            return 0;
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        }
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        int n = reader.read(b, off, len);
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        if (n <= 0) {
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            nextReader();
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            return read(b, off, len);
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        }
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        return n;
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    }
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    public void close() throws IOException {
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        do {
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            nextReader();
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        } while (reader != null);
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    }
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    void nextReader() throws IOException {
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        if (reader != null)
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            reader.close();
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        if (iterator.hasNext()) {
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            reader = (Reader) iterator.next();
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            if (reader == null)
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                throw new OXFException("Null reader passed to " + getClass().getName());
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        } else
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            reader = null;
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    }
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}