inputstreamimageinputstreamspi.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

/*
 * @(#)InputStreamImageInputStreamSpi.java	1.20 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.imageio.spi;

import java.io.File;
import java.io.InputStream;
import java.io.IOException;
import java.util.Locale;
import javax.imageio.spi.ImageInputStreamSpi;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.FileCacheImageInputStream;
import javax.imageio.stream.MemoryCacheImageInputStream;

public class InputStreamImageInputStreamSpi extends ImageInputStreamSpi {

    private static final String vendorName = "Sun Microsystems, Inc.";

    private static final String version = "1.0";

    private static final Class inputClass = InputStream.class;

    public InputStreamImageInputStreamSpi() {
        super(vendorName, version, inputClass);
    }

    public String getDescription(Locale locale) {
        return "Service provider that instantiates a FileCacheImageInputStream or MemoryCacheImageInputStream from an InputStream";
    }

    public boolean canUseCacheFile() {
        return true;
    }

    public boolean needsCacheFile() {
        return false;
    }

    public ImageInputStream createInputStreamInstance(Object input,
                                                      boolean useCache,
                                                      File cacheDir)
        throws IOException {
        if (input instanceof InputStream) {
            InputStream is = (InputStream)input;

            if (useCache) {
                return new FileCacheImageInputStream(is, cacheDir);
            } else {
                return new MemoryCacheImageInputStream(is);
            }
        } else {
            throw new IllegalArgumentException();
        }
    }
}