Package uk.ac.starlink.datanode.nodes

Class FITSDataNode

  • All Implemented Interfaces:
    DataNode
    Direct Known Subclasses:
    FITSFileDataNode, FITSStreamDataNode
    public abstract class FITSDataNode
extends DefaultDataNode
    Abstract DataNode class for representing FITS objects. Subclasses are provided for FITS objects on disk or in a stream.
    Author:
    Mark Taylor (Starlink)

    • Constructor Detail

      • FITSDataNode

        public FITSDataNode​(uk.ac.starlink.util.DataSource datsrc)
             throws NoSuchDataException
        Constructs a FITSDataNode from a data source.
        Parameters:
        datsrc - the source of the data
        Throws:
        NoSuchDataException

    • Method Detail

      • getName

        public java.lang.String getName()
        Description copied from interface: DataNode
        Gets the name of this object. This is an intrinsic property of the object.
        Specified by:
        getName in interface DataNode
        Overrides:
        getName in class DefaultDataNode
        Returns:
        the name of the object

      • getDescription

        public java.lang.String getDescription()
        Description copied from interface: DataNode
        Gets a concise description of this object. The form of the description will depend on the type of node, but it might detail the shape or type of data represented, or otherwise give some information additional to the name. It should not include the return value of the getName method, since they may be presented together. It should be on one line, and preferably no longer than around 70 characters. The null value may be returned if there is nothing to say.
        Specified by:
        getDescription in interface DataNode
        Overrides:
        getDescription in class DefaultDataNode
        Returns:
        a short string describing this object

      • allowsChildren

        public boolean allowsChildren()
        Description copied from class: DefaultDataNode
        The DefaultDataNode implementation of this method returns false.
        Specified by:
        allowsChildren in interface DataNode
        Overrides:
        allowsChildren in class DefaultDataNode
        Returns:
        true if the node is of a type which can have child nodes, false otherwise

      • getArrayData

        protected abstract FITSDataNode.ArrayDataMaker getArrayData​(long start,
                                                            long size)
        Returns an ArrayDataMaker encapsulating the same input stream as the on one which this FITSDataNode is based, but starting at a given offset start into the stream and size bytes long.
        Parameters:
        start - the offset into this FITSDataNode's stream at which the returned source's streams should start
        size - the number of bytes contained by the returned source's stream

      • getChildIterator

        public java.util.Iterator getChildIterator()
        Description copied from class: DefaultDataNode
        The DefaultDataNode implementation of this method throws UnsupportedOperationException (DefaultDataNode.allowsChildren() is false).
        Specified by:
        getChildIterator in interface DataNode
        Overrides:
        getChildIterator in class DefaultDataNode
        Returns:
        an Iterator over the children. Each object iterated over should be a DataNode. Behaviour is undefined if this method is called on an object for which allowsChildren returns false.

      • getNodeType

        public java.lang.String getNodeType()
        Description copied from interface: DataNode
        Returns a short sentence indicating what kind of node this is. The return value should be just a few words. As a rough guideline it should indicate what the implementing class is.
        Specified by:
        getNodeType in interface DataNode
        Overrides:
        getNodeType in class DefaultDataNode
        Returns:
        a short description of the type of this DataNode

      • getDataInput

        protected nom.tam.util.ArrayDataInput getDataInput()
                                            throws java.io.IOException
        Returns an ArrayDataInput object containing the data from this FITS object.
        Throws:
        java.io.IOException

      • isMagic

        public static boolean isMagic​(byte[] buffer)
        Indicates whether a buffer of bytes looks like the start of a FITS file.
        Parameters:
        buffer - the first few bytes of a potential stream
        Returns:
        true if buffer matches the FITS file magic number