Package uk.ac.starlink.array
Class NDArrayFactory
- java.lang.Object
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- uk.ac.starlink.array.NDArrayFactory
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public class NDArrayFactory extends java.lang.Object
Manufactures NDArray objects from URLs. Methods are available to construct a readable NDArray from a URL pointing to an existing array resource, or to construct a new NDArray with a location given by a URL.This factory delegates the actual NDArray creation to external ArrayBuilder objects; the URL is passed to each one in turn until one can make an NDArray object from it, which object is returned to the caller.
By default, if the corresponding classes are present, the following ArrayBuilders are installed:
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uk.ac.starlink.hds.HDSArrayBuilder
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uk.ac.starlink.fits.FitsArrayBuilder
- Author:
- Mark Taylor (Starlink)
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Constructor Summary
Constructors Constructor Description NDArrayFactory()
Constructs an NDArrayFactory with a default list of builders.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.util.List
getBuilders()
Gets the list of builders which actually do the URL->NDArray construction.NDArray
makeNDArray(java.lang.String location, AccessMode mode)
Constructs a readable NDArray from a location representing an existing resource.NDArray
makeNDArray(java.net.URL url, AccessMode mode)
Constructs a readable NDArray from a URL representing an exisiting resource.NDArray
makeNewNDArray(java.lang.String location, NDArray template)
Constructs a new NDArray to which data can be written given a location and another template NDArray.NDArray
makeNewNDArray(java.lang.String location, NDShape shape, Type type, BadHandler bh)
Constructs a new NDArray to which data can be written given a location and the array characteristics.NDArray
makeNewNDArray(java.net.URL url, NDArray template)
Constructs a new NDArray to which data can be written given a URL and another template NDArray.NDArray
makeNewNDArray(java.net.URL url, NDShape shape, Type type, BadHandler bh)
Constructs a new NDArray to which data can be written given a URL and the array characteristics.void
setBuilders(ArrayBuilder[] builders)
Sets the list of builders which actually do the URL->NDArray construction Builders earlier in the list are given a chance to handle a URL before ones later in the list.
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Method Detail
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getBuilders
public java.util.List getBuilders()
Gets the list of builders which actually do the URL->NDArray construction. Builders earlier in the list are given a chance to handle a URL before ones later in the list. This list may be modified to change the behaviour of the NDArrayFactory.- Returns:
- a mutable List of
ArrayBuilder
objects used for turning URLs into NDArrays
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setBuilders
public void setBuilders(ArrayBuilder[] builders)
Sets the list of builders which actually do the URL->NDArray construction Builders earlier in the list are given a chance to handle a URL before ones later in the list.- Parameters:
builders
- an array of ArrayBuilder objects used for turning URLs into NDArrays
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makeNDArray
public NDArray makeNDArray(java.net.URL url, AccessMode mode) throws java.io.IOException
Constructs a readable NDArray from a URL representing an exisiting resource. A null result will be returned if none of the available builders understands the URL; an IOException will result if one of the builders is willing to handle the URL but fails to find an array resource at it.- Parameters:
url
- a URL pointing to a resource holding array datamode
- the mode with which it should be accessed- Returns:
- a readable NDArray object view of the data at url, or null if one could not be found
- Throws:
java.io.IOException
- if there is any I/O error
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makeNewNDArray
public NDArray makeNewNDArray(java.net.URL url, NDShape shape, Type type, BadHandler bh) throws java.io.IOException
Constructs a new NDArray to which data can be written given a URL and the array characteristics. A null result will be returned if none of the available builders understands the URL; an IOException will result if one of the builders is willing to handle the URL but fails to make an array resource at it.The bh parameter indicates a requested bad value handling scheme, but does not guarantee that it will be used, since not all storage formats are capable of storing bad values in arbitrary ways. According to the resource type, bad value handling will be provided on a best-efforts basis. If bh is null, the implementation will choose a bad value handling policy of its own.
- Parameters:
url
- a URL pointing to a writable resource. This may be a suitablefile:
-protocol URL or one with some other protocol which can provide an output-capable connectionshape
- the shape of the new arraytype
- a Type object indicating the type of data in the arraybh
- the requested bad value handling policy - see above.- Returns:
- a new writable NDArray object with the given URL, or null if none could be constructed because none of the handlers recognised the URL
- Throws:
java.io.IOException
- if an I/O error occursjava.lang.IllegalArgumentException
- if the type of bh does not match type
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makeNewNDArray
public NDArray makeNewNDArray(java.net.URL url, NDArray template) throws java.io.IOException
Constructs a new NDArray to which data can be written given a URL and another template NDArray. This convenience method simply callsmakeNewNDArray(URL,NDShape,Type,BadHandler)
with the shape, type and bh parameters copied from the template NDArray.- Parameters:
url
- a URL pointing to a writable resource. This may be a suitablefile:
-protocol URL or one with some other protocol which can provide an output-capable connectiontemplate
- an NDArray whose characteristics are to be copied when the new one is created- Returns:
- a new writable NDArray object with the given URL
- Throws:
java.io.IOException
- if an I/O error occurs
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makeNDArray
public NDArray makeNDArray(java.lang.String location, AccessMode mode) throws java.io.IOException
Constructs a readable NDArray from a location representing an existing resource. This convenience method just turns the location into a URL and callsmakeNDArray(URL,AccessMode)
.- Parameters:
location
- the location of the resource. If it cannot be parsed as a URL, it will be treated as a filenamemode
- the mode with which it should be accessed- Returns:
- a readable NDArray object view of the data at location, or null if one could not be found
- Throws:
java.io.IOException
- if there is any I/O error
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makeNewNDArray
public NDArray makeNewNDArray(java.lang.String location, NDShape shape, Type type, BadHandler bh) throws java.io.IOException
Constructs a new NDArray to which data can be written given a location and the array characteristics. This convenience method just turns the location into a URL and callsmakeNewNDArray(URL,NDShape,Type,BadHandler)
- Parameters:
location
- the location of the resource. If it cannot be parsed as a URL, it will be treated as a filenameshape
- the shape of the new arraytype
- a Type object indicating the type of data in the arraybh
- requested bad value handling policy- Returns:
- a new writable NDArray object at the given location, or null if none could be constructed because none of the handlers recognised the URL
- Throws:
java.io.IOException
- if an I/O error occurs
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makeNewNDArray
public NDArray makeNewNDArray(java.lang.String location, NDArray template) throws java.io.IOException
Constructs a new NDArray to which data can be written given a location and another template NDArray. This convenience method just turns the location into a URL and callsmakeNewNDArray(URL,NDArray)
.- Parameters:
location
- the location of the resource. If it cannot be parsed as a URL, it will be treated as a filenametemplate
- an NDArray whose characteristics are to be copied when the new one is created- Returns:
- a new writable NDArray object at the given location
- Throws:
java.io.IOException
- if an I/O error occurs
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