javax.imageio.spi: abstract public class: ImageInputStreamSpi

javax.imageio.spi
abstract public class: ImageInputStreamSpi [javadoc | source]

java.lang.Object
   javax.imageio.spi.IIOServiceProvider
      javax.imageio.spi.ImageInputStreamSpi

All Implemented Interfaces:
RegisterableService

The service provider interface (SPI) for ImageInputStreams. For more information on service provider interfaces, see the class comment for the IIORegistry class.

This interface allows arbitrary objects to be "wrapped" by instances of ImageInputStream. For example, a particular ImageInputStreamSpi might allow a generic InputStream to be used as an input source; another might take input from a URL.

By treating the creation of ImageInputStreams as a pluggable service, it becomes possible to handle future input sources without changing the API. Also, high-performance implementations of ImageInputStream (for example, native implementations for a particular platform) can be installed and used transparently by applications.

Also see:

IIORegistry

javax.imageio.stream.ImageInputStream

Field Summary
protected Class	inputClass	A `Class` object indicating the legal object type for use by the `createInputStreamInstance` method.

Fields inherited from javax.imageio.spi.IIOServiceProvider:
vendorName, version

Constructor:

Constructor:
protected ImageInputStreamSpi() { } Constructs a blank `ImageInputStreamSpi`. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods.
public ImageInputStreamSpi(String vendorName, String version, Class inputClass) { super(vendorName, version); this.inputClass = inputClass; } Constructs an `ImageInputStreamSpi` with a given set of values. Parameters: `vendorName` - the vendor name. `version` - a version identifier. `inputClass` - a `Class` object indicating the legal object type for use by the `createInputStreamInstance` method. Throws: `IllegalArgumentException` - if `vendorName` is `null`. `IllegalArgumentException` - if `version` is `null`. exception: `IllegalArgumentException` - if `vendorName` is `null`. exception: `IllegalArgumentException` - if `version` is `null`.

 protected ImageInputStreamSpi() {

}

Constructs a blank ImageInputStreamSpi. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods.

 public ImageInputStreamSpi(String vendorName,
    String version,
    Class inputClass) {
        super(vendorName, version);
        this.inputClass = inputClass;
}

ImageInputStreamSpi

Parameters:

vendorName - the vendor name.

version - a version identifier.

inputClass - a Class object indicating the legal object type for use by the createInputStreamInstance method.

Throws:

IllegalArgumentException - if vendorName is null.

IllegalArgumentException - if version is null.

exception: IllegalArgumentException - if vendorName is null.

exception: IllegalArgumentException - if version is null.

Method from javax.imageio.spi.ImageInputStreamSpi Summary:
canUseCacheFile, createInputStreamInstance, createInputStreamInstance, getInputClass, needsCacheFile

Methods from javax.imageio.spi.IIOServiceProvider:
getDescription, getVendorName, getVersion, onDeregistration, onRegistration

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from javax.imageio.spi.ImageInputStreamSpi Detail:
public boolean canUseCacheFile() { return false; } Returns `true` if the `ImageInputStream` implementation associated with this service provider can optionally make use of a cache file for improved performance and/or memory footrprint. If `false`, the value of the `useCache` argument to `createInputStreamInstance` will be ignored. The default implementation returns `false`.
public ImageInputStream createInputStreamInstance(Object input) throws IOException { return createInputStreamInstance(input, true, null); } Returns an instance of the `ImageInputStream` implementation associated with this service provider. A cache file will be created in the system-dependent default temporary-file directory, if needed.
abstract public ImageInputStream createInputStreamInstance(Object input, boolean useCache, File cacheDir) throws IOException Returns an instance of the `ImageInputStream` implementation associated with this service provider. If the use of a cache file is optional, the `useCache` parameter will be consulted. Where a cache is required, or not applicable, the value of `useCache` will be ignored.
public Class getInputClass() { return inputClass; } Returns a `Class` object representing the class or interface type that must be implemented by an input source in order to be "wrapped" in an `ImageInputStream` via the `createInputStreamInstance` method. Typical return values might include `InputStream.class` or `URL.class`, but any class may be used.
public boolean needsCacheFile() { return false; } Returns `true` if the `ImageInputStream` implementation associated with this service provider requires the use of a cache `File`. If `true`, the value of the `useCache` argument to `createInputStreamInstance` will be ignored. The default implementation returns `false`.

Method from javax.imageio.spi.ImageInputStreamSpi Detail:

 public boolean canUseCacheFile() {
        return false;
}

true

ImageInputStream

false

useCache

createInputStreamInstance

The default implementation returns false.

 public ImageInputStream createInputStreamInstance(Object input) throws IOException {
        return createInputStreamInstance(input, true, null);
}

ImageInputStream

 abstract public ImageInputStream createInputStreamInstance(Object input,
    boolean useCache,
    File cacheDir) throws IOExceptionReturns an instance of the ImageInputStream
implementation associated with this service provider. If the
use of a cache file is optional, the useCache
parameter will be consulted. Where a cache is required, or
not applicable, the value of useCache will be ignored.

 public Class getInputClass() {
        return inputClass;
}

Class

ImageInputStream

createInputStreamInstance

Typical return values might include InputStream.class or URL.class, but any class may be used.

 public boolean needsCacheFile() {
        return false;
}

true

ImageInputStream

File

true

useCache

createInputStreamInstance

The default implementation returns false.