Package org.esa.snap.core.gpf

Class OperatorSpi

java.lang.Object
org.esa.snap.core.gpf.OperatorSpi
Direct Known Subclasses:
BandMathsOp.Spi, GraphOp.Spi, ImportVectorOp.Spi, MergeOp.Spi, MosaicOp.Spi, PassThroughOp.Spi, ProductSetReaderOp.Spi, QuantizationOp.Spi, RasterToVectorOp.Spi, ReadOp.Spi, ReprojectionOp.Spi, ResamplingOp.Spi, SubsetOp.Spi, ToolAdapterOpSpi, WriteOp.Spi, WriteRGBOp.Spi
public abstract class OperatorSpi extends Object

The OperatorSpi class is the service provider interface (SPI) for Operators. Therefore this abstract class is intended to be derived by clients.

The SPI is both a descriptor for the operator type and a factory for new Operator instances.

An SPI is required for your operator if you want to make it accessible via an alias name in the various GPF.create methods or within GPF Graph XML code.

SPI are registered either pragmatically using the OperatorSpiRegistry or automatically via standard Java services lookup mechanism. For the services approach, place a file META-INF/services/org.esa.snap.core.gpf.OperatorSpi in the JAR file containing your operators and associated SPIs. For each SPI to be automatically registered, place a text line in the file containing the SPI's fully qualified class name.

Since:
4.1

  • Constructor Details

    • OperatorSpi

      protected OperatorSpi(OperatorDescriptor operatorDescriptor)
      Constructs an operator SPI for the given operator descriptor.
      Parameters:
      operatorDescriptor - The operator descriptor.
      Since:
      BEAM 5

    • OperatorSpi

      protected OperatorSpi(URL operatorDescriptorUrl)
      Constructs an operator SPI for the given URL pointing to a valid operator descriptor XML document.
      Parameters:
      operatorDescriptorUrl - The operator descriptor URL.
      Since:
      BEAM 5

    • OperatorSpi

      protected OperatorSpi(Class<? extends Operator> operatorClass)
      Constructs an operator SPI for the given operator class. The alias name and other metadata will be taken from the operator annotation OperatorMetadata. If no such exists, the alias name will be the operator's class name without the package path. All other metadata will be set to the empty string.
      Parameters:
      operatorClass - The operator class.

    • OperatorSpi

      @Deprecated protected OperatorSpi(Class<? extends Operator> operatorClass, String operatorAlias)
      Deprecated.
      since BEAM 5, no replacement.
      Constructs an operator SPI for the given class name and alias name.
      Parameters:
      operatorClass - The operator class.
      operatorAlias - The alias name for the operator.

  • Method Details

    • createOperator

      public Operator createOperator() throws OperatorException

      Creates an operator instance with no arguments. The default implementation calls the default constructor. If no such is defined in the operator, an exception is thrown.

      This method may be overridden by clients in order to provide a no-argument instance of their operator. Implementors should call operator.setSpi(this) in order to set the operator's SPI.

      Returns:
      the operator instance
      Throws:
      OperatorException - if the instance could not be created

    • createOperator

      public Operator createOperator(Map<String,Object> parameters, Map<String,Product> sourceProducts) throws OperatorException

      Creates an operator instance for the given source products and processing parameters.

      This method may be overridden by clients in order to process the passed parameters and source products and optionally construct the operator in a specific way. Implementors should call operator.setSpi(this) in order to set the operator's SPI.

      Parameters:
      parameters - the processing parameters.
      sourceProducts - the source products.
      Returns:
      the operator instance.
      Throws:
      OperatorException - if the operator could not be created.

    • createOperator

      public Operator createOperator(Map<String,Object> parameters, Map<String,Product> sourceProducts, RenderingHints renderingHints) throws OperatorException

      Creates an operator instance for the given source products and processing parameters.

      This method may be overridden by clients in order to process the passed parameters and source products and optionally construct the operator in a specific way. Implementors should call operator.setSpi(this) in order to set the operator's SPI.

      Parameters:
      parameters - the processing parameters.
      sourceProducts - the source products.
      renderingHints - the rendering hints, may be null.
      Returns:
      the operator instance.
      Throws:
      OperatorException - if the operator could not be created.

    • getOperatorClass

      public final Class<? extends Operator> getOperatorClass()
      Gets the operator implementation class. The operator class must be public and provide a public zero-argument constructor.

      Shorthand for getOperatorDescriptor().getOperatorClass().

      Returns:
      The operator implementation class.

    • getOperatorAlias

      public final String getOperatorAlias()
      The alias name under which the operator can be accessed.

      Shorthand for getOperatorDescriptor().getAlias().

      Returns:
      The alias name of the (@link Operator), or null if not declared.

    • getModuleMetadata

      public ModuleMetadata getModuleMetadata()
      The metadata information of the module which holds the operator provided by this SPI.
      Returns:
      the module metadata

    • getOperatorDescriptor

      public OperatorDescriptor getOperatorDescriptor()
      Returns:
      The operator descriptor.
      Since:
      BEAM 5

    • getOperatorAlias

      public static String getOperatorAlias(Class<? extends Operator> operatorClass)
      Gets the alias name of the operator given by it's class. The method returns the 'alias' element of the operator's OperatorMetadata, if any. Otherwise it returns the class' simple name (without package path).
      Parameters:
      operatorClass - The operator class.
      Returns:
      An operator alias name.