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/*
 * Copyright 2000,2005 wingS development team.
 *
 * This file is part of wingS (http://wingsframework.org).
 *
 * wingS is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * Please see COPYING for the complete licence.
 */
package org.wings.template;

import java.io.IOException;
import java.io.InputStream;

/**
 * A StreamDataSource implements a DataSource
 * as a wrapper around a Stream.
 *
 * @author Joachim Karrer
 */
public class StreamTemplateSource implements TemplateSource {
    /**
     * enable debug output
     */
    private static final boolean DEBUG = true;

    /**
     * the InputStream from which we are reading data.
     */
    private transient InputStream iStream;

    /**
     * the last time the InputStream was updated.
     */
    private long modificationTime;

    /**
     * generates a new StreamDataSource with the given Stream
     *
     * @param iStream the InputStream from which the template is read.
     */
    public StreamTemplateSource(InputStream iStream) {
        setInputStream(iStream);
    }

    /**
     * sets the InputStream and the modificationTime
     *
     * @param iStream the InputStream from which the template is read.
     */
    public void setInputStream(InputStream iStream) {
        if (iStream == null) {
            throw new IllegalArgumentException("stream is null, this is invalid!!");
        }
        this.iStream = iStream;
        setModificationTime();
    }

    /**
     * sets the modificationTime to the currentTimeMillis
     */
    public void setModificationTime() {
        modificationTime = System.currentTimeMillis();
    }

    /**
     * returns the canonical name of the inputStream (uaaaah!)
     *
     * @return always null, because stream is always to be parsed
     */
    @Override
    public String getCanonicalName() {
        return null;
    }

    /**
     * Returns the time the content of this stream
     * was last modified.
     * The return value is used to decide whether to reparse a
     * Source or not. Reparsing is done if the value returned
     * here differs from the value returned at the last processing
     * time.
     * Attention: Modificationtime is only updated if a new stream is set!
     *
     * @return long a modification time
     */
    @Override
    public long lastModified() {
        return modificationTime;
    }

    /**
     * Gets an InputStream of the File.
     *
     * @return the actually set InputStream
     */
    @Override
    public InputStream getInputStream() throws IOException {
        iStream.reset();
        return iStream;
    }
}