InputStreamContent.java

/*
 * InputStreamContent
 */
package gov.usgs.earthquake.product;

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

import gov.usgs.util.StreamUtils;

/**
 * Content within an InputStream.
 */
public class InputStreamContent extends AbstractContent {

    /** The actual content. */
    private InputStream content;

    /**
     * Create a new InputStream content.
     *
     * @param content
     *            the content.
     */
    public InputStreamContent(final InputStream content) {
        this.content = content;
    }

    /**
     * Create an InputStreamContent from another Content.
     *
     * @param content
     *            the content to duplicate.
     * @throws IOException
     *            if IO error occurs
     */
    public InputStreamContent(final Content content) throws IOException {
        super(content);
        this.content = content.getInputStream();
    }

    /**
     * @return InputStream to content.
     */
    public InputStream getInputStream() throws IOException {
        return content;
    }

    /**
     * InputStream can only be read once.
     *
     * <p>If sha256 is null, read and convert to in memory stream.
     */
    public String getSha256() throws Exception {
        String sha256 = super.getSha256(false);
        if (sha256 == null) {
            // convert stream into byte array to read multiple times
            final byte[] contentBytes;
            try (final InputStream in = getInputStream()) {
                contentBytes = StreamUtils.readStream(in);
            }
            // generate sha256 from byte stream
            this.content = new ByteArrayInputStream(contentBytes);
            sha256 = super.getSha256();
            // set byte stream for next reader
            this.content = new ByteArrayInputStream(contentBytes);
        }
        return sha256;
    }

    /**
     * Free any resources associated with this content.
     */
    public void close() {
        StreamUtils.closeStream(content);
        content = null;
    }
}