File	Doc	Category	Size	Date	Package
IIOMetadata.java	API Doc	Java SE 5 API	35209	Fri Aug 26 14:57:30 BST 2005	javax.imageio.metadata

IIOMetadata

• java.lang.Object

Fields Summary
protected boolean	standardFormatSupported A boolean indicating whether the concrete subclass supports the standard metadata format, set via the constructor.
protected String	nativeMetadataFormatName The name of the native metadata format for this object, initialized to null and set via the constructor.
protected String	nativeMetadataFormatClassName The name of the class implementing IIOMetadataFormat and representing the native metadata format, initialized to null and set via the constructor.
protected String[]	extraMetadataFormatNames An array of names of formats, other than the standard and native formats, that are supported by this plug-in, initialized to null and set via the constructor.
protected String[]	extraMetadataFormatClassNames An array of names of classes implementing IIOMetadataFormat and representing the metadata formats, other than the standard and native formats, that are supported by this plug-in, initialized to null and set via the constructor.
protected IIOMetadataController	defaultController An IIOMetadataController that is suggested for use as the controller for this IIOMetadata object. It may be retrieved via getDefaultController. To install the default controller, call setController(getDefaultController()). This instance variable should be set by subclasses that choose to provide their own default controller, usually a GUI, for setting parameters.
protected IIOMetadataController	controller The IIOMetadataController that will be used to provide settings for this IIOMetadata object when the activateController method is called. This value overrides any default controller, even when null.

Constructors Summary
protected IIOMetadata() Constructs an empty IIOMetadata object. The subclass is responsible for suppying values for all protected instance variables that will allow any non-overridden default implemtations of methods to satisfy their contracts. For example, extraMetadataFormatNames should not have length 0.
protected IIOMetadata(boolean standardMetadataFormatSupported, String nativeMetadataFormatName, String nativeMetadataFormatClassName, String[] extraMetadataFormatNames, String[] extraMetadataFormatClassNames) Constructs an IIOMetadata object with the given format names and format class names, as well as a boolean indicating whether the standard format is supported. This constructor does not attempt to check the class names for validity. Invalid class names may cause exceptions in subsequent calls to getMetadataFormat. param standardMetadataFormatSupported true if this object can return or accept a DOM tree using the standard metadata format. param nativeMetadataFormatName the name of the native metadata format, as a String, or null if there is no native format. param nativeMetadataFormatClassName the name of the class of the native metadata format, or null if there is no native format. param extraMetadataFormatNames an array of Strings indicating additional formats supported by this object, or null if there are none. param extraMetadataFormatClassNames an array of Strings indicating the class names of any additional formats supported by this object, or null if there are none. exception IllegalArgumentException if extraMetadataFormatNames has length 0. exception IllegalArgumentException if extraMetadataFormatNames and extraMetadataFormatClassNames are neither both null, nor of the same length. this.standardFormatSupported = standardMetadataFormatSupported; this.nativeMetadataFormatName = nativeMetadataFormatName; this.nativeMetadataFormatClassName = nativeMetadataFormatClassName; if (extraMetadataFormatNames != null) { if (extraMetadataFormatNames.length == 0) { throw new IllegalArgumentException ("extraMetadataFormatNames.length == 0!"); } if (extraMetadataFormatClassNames == null) { throw new IllegalArgumentException ("extraMetadataFormatNames != null && extraMetadataFormatClassNames == null!"); } if (extraMetadataFormatClassNames.length != extraMetadataFormatNames.length) { throw new IllegalArgumentException ("extraMetadataFormatClassNames.length != extraMetadataFormatNames.length!"); } this.extraMetadataFormatNames = (String[]) extraMetadataFormatNames.clone(); this.extraMetadataFormatClassNames = (String[]) extraMetadataFormatClassNames.clone(); } else { if (extraMetadataFormatClassNames != null) { throw new IllegalArgumentException ("extraMetadataFormatNames == null && extraMetadataFormatClassNames != null!"); } }

Methods Summary
public boolean	activateController() Activates the installed IIOMetadataController for this IIOMetadata object and returns the resulting value. When this method returns true, all values for this IIOMetadata object will be ready for the next write operation. If false is returned, no settings in this object will have been disturbed (i.e., the user canceled the operation). Ordinarily, the controller will be a GUI providing a user interface for a subclass of IIOMetadata for a particular plug-in. Controllers need not be GUIs, however. The default implementation calls getController and the calls activate on the returned object if hasController returns true. return true if the controller completed normally. exception IllegalStateException if there is no controller currently installed. see IIOMetadataController see #setController(IIOMetadataController) see #getController see #getDefaultController see #hasController if (!hasController()) { throw new IllegalStateException("hasController() == false!"); } return getController().activate(this);
private void	append(javax.imageio.metadata.IIOMetadataNode root, javax.imageio.metadata.IIOMetadataNode node) Appends a new node to an existing node, if the new node is non-null. if (node != null) { root.appendChild(node); }
public abstract org.w3c.dom.Node	getAsTree(java.lang.String formatName) Returns an XML DOM Node object that represents the root of a tree of metadata contained within this object according to the conventions defined by a given metadata format. The names of the available metadata formats may be queried using the getMetadataFormatNames method. param formatName the desired metadata format. return an XML DOM Node object forming the root of a tree. exception IllegalArgumentException if formatName is null or is not one of the names returned by getMetadataFormatNames. see #getMetadataFormatNames see #setFromTree see #mergeTree
public javax.imageio.metadata.IIOMetadataController	getController() Returns whatever IIOMetadataController is currently installed. This could be the default if there is one, null, or the argument of the most recent call to setController. The default implementation returns the value of the controller instance variable. return the currently installed IIOMetadataController, or null. see IIOMetadataController see #setController see #getDefaultController see #hasController see #activateController() return controller;
public javax.imageio.metadata.IIOMetadataController	getDefaultController() Returns the default IIOMetadataController, if there is one, regardless of the currently installed controller. If there is no default controller, returns null. The default implementation returns the value of the defaultController instance variable. return the default IIOMetadataController, or null. see IIOMetadataController see #setController(IIOMetadataController) see #getController see #hasController see #activateController() return defaultController;
public java.lang.String[]	getExtraMetadataFormatNames() Returns an array of Strings containing the names of additional metadata formats, other than the native and standard formats, recognized by this plug-in's getAsTree, setFromTree, and mergeTree methods. If there are no such additional formats, null is returned. The default implementation returns a clone of the extraMetadataFormatNames instance variable. return an array of Strings with length at least 1, or null. see #getAsTree see #setFromTree see #mergeTree see #getNativeMetadataFormatName see #getMetadataFormatNames if (extraMetadataFormatNames == null) { return null; } return (String[])extraMetadataFormatNames.clone();
public javax.imageio.metadata.IIOMetadataFormat	getMetadataFormat(java.lang.String formatName) Returns an IIOMetadataFormat object describing the given metadata format, or null if no description is available. The supplied name must be one of those returned by getMetadataFormatNames (i.e., either the native format name, the standard format name, or one of those returned by getExtraMetadataFormatNames). The default implementation checks the name against the global standard metadata format name, and returns that format if it is supported. Otherwise, it checks against the native format names followed by any additional format names. If a match is found, it retrieves the name of the IIOMetadataFormat class from nativeMetadataFormatClassName or extraMetadataFormatClassNames as appropriate, and constructs an instance of that class using its getInstance method. param formatName the desired metadata format. return an IIOMetadataFormat object. exception IllegalArgumentException if formatName is null or is not one of the names recognized by the plug-in. exception IllegalStateException if the class corresponding to the format name cannot be loaded. if (formatName == null) { throw new IllegalArgumentException("formatName == null!"); } if (standardFormatSupported && formatName.equals (IIOMetadataFormatImpl.standardMetadataFormatName)) { return IIOMetadataFormatImpl.getStandardFormatInstance(); } String formatClassName = null; if (formatName.equals(nativeMetadataFormatName)) { formatClassName = nativeMetadataFormatClassName; } else if (extraMetadataFormatNames != null) { for (int i = 0; i < extraMetadataFormatNames.length; i++) { if (formatName.equals(extraMetadataFormatNames[i])) { formatClassName = extraMetadataFormatClassNames[i]; break; // out of for } } } if (formatClassName == null) { throw new IllegalArgumentException("Unsupported format name"); } try { Class cls = null; final Object o = this; // firstly we try to use classloader used for loading // the IIOMetadata implemantation for this plugin. ClassLoader loader = (ClassLoader) java.security.AccessController.doPrivileged( new java.security.PrivilegedAction() { public Object run() { return o.getClass().getClassLoader(); } }); try { cls = Class.forName(formatClassName, true, loader); } catch (ClassNotFoundException e) { // we failed to load IIOMetadataFormat class by // using IIOMetadata classloader.Next try is to // use thread context classloader. loader = (ClassLoader) java.security.AccessController.doPrivileged( new java.security.PrivilegedAction() { public Object run() { return Thread.currentThread().getContextClassLoader(); } }); try { cls = Class.forName(formatClassName, true, loader); } catch (ClassNotFoundException e1) { // finally we try to use system classloader in case // if we failed to load IIOMetadataFormat implementation // class above. cls = Class.forName(formatClassName, true, ClassLoader.getSystemClassLoader()); } } Method meth = cls.getMethod("getInstance", null); return (IIOMetadataFormat) meth.invoke(null, null); } catch (Exception e) { RuntimeException ex = new IllegalStateException ("Can't obtain format"); ex.initCause(e); throw ex; }
public java.lang.String[]	getMetadataFormatNames() Returns an array of Strings containing the names of all metadata formats, including the native and standard formats, recognized by this plug-in's getAsTree, setFromTree, and mergeTree methods. If there are no such formats, null is returned. The default implementation calls getNativeMetadataFormatName, isStandardMetadataFormatSupported, and getExtraMetadataFormatNames and returns the combined results. return an array of Strings. see #getNativeMetadataFormatName see #isStandardMetadataFormatSupported see #getExtraMetadataFormatNames String nativeName = getNativeMetadataFormatName(); String standardName = isStandardMetadataFormatSupported() ? IIOMetadataFormatImpl.standardMetadataFormatName : null; String[] extraNames = getExtraMetadataFormatNames(); int numFormats = 0; if (nativeName != null) { ++numFormats; } if (standardName != null) { ++numFormats; } if (extraNames != null) { numFormats += extraNames.length; } if (numFormats == 0) { return null; } String[] formats = new String[numFormats]; int index = 0; if (nativeName != null) { formats[index++] = nativeName; } if (standardName != null) { formats[index++] = standardName; } if (extraNames != null) { for (int i = 0; i < extraNames.length; i++) { formats[index++] = extraNames[i]; } } return formats;
public java.lang.String	getNativeMetadataFormatName() Returns the name of the "native" metadata format for this plug-in, which typically allows for lossless encoding and transmission of the metadata stored in the format handled by this plug-in. If no such format is supported, nullwill be returned. The structure and contents of the "native" metadata format are defined by the plug-in that created this IIOMetadata object. Plug-ins for simple formats will usually create a dummy node for the root, and then a series of child nodes representing individual tags, chunks, or keyword/value pairs. A plug-in may choose whether or not to document its native format. The default implementation returns the value of the nativeMetadataFormatName instance variable. return the name of the native format, or null. see #getExtraMetadataFormatNames see #getMetadataFormatNames return nativeMetadataFormatName;
protected javax.imageio.metadata.IIOMetadataNode	getStandardChromaNode() Returns an IIOMetadataNode representing the chroma information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardCompressionNode() Returns an IIOMetadataNode representing the compression information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardDataNode() Returns an IIOMetadataNode representing the data format information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardDimensionNode() Returns an IIOMetadataNode representing the dimension information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardDocumentNode() Returns an IIOMetadataNode representing the document information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardTextNode() Returns an IIOMetadataNode representing the textual information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardTileNode() Returns an IIOMetadataNode representing the tiling information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. see #getStandardTree return null;
protected javax.imageio.metadata.IIOMetadataNode	getStandardTransparencyNode() Returns an IIOMetadataNode representing the transparency information of the standard javax_imageio_1.0 metadata format, or null if no such information is available. This method is intended to be called by the utility routine getStandardTree. The default implementation returns null. Subclasses should override this method to produce an appropriate subtree if they wish to support the standard metadata format. return an IIOMetadataNode, or null. return null;
protected final javax.imageio.metadata.IIOMetadataNode	getStandardTree() A utility method to return a tree of IIOMetadataNodes representing the metadata contained within this object according to the conventions of the standard javax_imageio_1.0 metadata format. This method calls the various getStandard*Node methods to supply each of the subtrees rooted at the children of the root node. If any of those methods returns null, the corresponding subtree will be omitted. If all of them return null, a tree consisting of a single root node will be returned. return an IIOMetadataNode representing the root of a metadata tree in the javax_imageio_1.0 format. see #getStandardChromaNode see #getStandardCompressionNode see #getStandardDataNode see #getStandardDimensionNode see #getStandardDocumentNode see #getStandardTextNode see #getStandardTileNode see #getStandardTransparencyNode IIOMetadataNode root = new IIOMetadataNode (IIOMetadataFormatImpl.standardMetadataFormatName); append(root, getStandardChromaNode()); append(root, getStandardCompressionNode()); append(root, getStandardDataNode()); append(root, getStandardDimensionNode()); append(root, getStandardDocumentNode()); append(root, getStandardTextNode()); append(root, getStandardTileNode()); append(root, getStandardTransparencyNode()); return root;
public boolean	hasController() Returns true if there is a controller installed for this IIOMetadata object. The default implementation returns true if the getController method returns a non-null value. return true if a controller is installed. see IIOMetadataController see #setController(IIOMetadataController) see #getController see #getDefaultController see #activateController() return (getController() != null);
public abstract boolean	isReadOnly() Returns true if this object does not support the mergeTree, setFromTree, and reset methods. return true if this IIOMetadata object cannot be modified.
public boolean	isStandardMetadataFormatSupported() Returns true if the standard metadata format is supported by getMetadataFormat, getAsTree, setFromTree, and mergeTree. The default implementation returns the value of the standardFormatSupported instance variable. return true if the standard metadata format is supported. see #getAsTree see #setFromTree see #mergeTree see #getMetadataFormat return standardFormatSupported;
public abstract void	mergeTree(java.lang.String formatName, org.w3c.dom.Node root) Alters the internal state of this IIOMetadata object from a tree of XML DOM Nodes whose syntax is defined by the given metadata format. The previous state is altered only as necessary to accomodate the nodes that are present in the given tree. If the tree structure or contents are invalid, an IIOInvalidTreeException will be thrown. As the semantics of how a tree or subtree may be merged with another tree are completely format-specific, plug-in authors may implement this method in whatever manner is most appropriate for the format, including simply replacing all existing state with the contents of the given tree. param formatName the desired metadata format. param root an XML DOM Node object forming the root of a tree. exception IllegalStateException if this object is read-only. exception IllegalArgumentException if formatName is null or is not one of the names returned by getMetadataFormatNames. exception IllegalArgumentException if root is null. exception IIOInvalidTreeException if the tree cannot be parsed successfully using the rules of the given format. see #getMetadataFormatNames see #getAsTree see #setFromTree
public abstract void	reset() Resets all the data stored in this object to default values, usually to the state this object was in immediately after construction, though the precise semantics are plug-in specific. Note that there are many possible default values, depending on how the object was created. exception IllegalStateException if this object is read-only. see javax.imageio.ImageReader#getStreamMetadata see javax.imageio.ImageReader#getImageMetadata see javax.imageio.ImageWriter#getDefaultStreamMetadata see javax.imageio.ImageWriter#getDefaultImageMetadata
public void	setController(javax.imageio.metadata.IIOMetadataController controller) Sets the IIOMetadataController to be used to provide settings for this IIOMetadata object when the activateController method is called, overriding any default controller. If the argument is null, no controller will be used, including any default. To restore the default, use setController(getDefaultController()). The default implementation sets the controller instance variable to the supplied value. param controller An appropriate IIOMetadataController, or null. see IIOMetadataController see #getController see #getDefaultController see #hasController see #activateController() this.controller = controller;
public void	setFromTree(java.lang.String formatName, org.w3c.dom.Node root) Sets the internal state of this IIOMetadata object from a tree of XML DOM Nodes whose syntax is defined by the given metadata format. The previous state is discarded. If the tree's structure or contents are invalid, an IIOInvalidTreeException will be thrown. The default implementation calls reset followed by mergeTree(formatName, root). param formatName the desired metadata format. param root an XML DOM Node object forming the root of a tree. exception IllegalStateException if this object is read-only. exception IllegalArgumentException if formatName is null or is not one of the names returned by getMetadataFormatNames. exception IllegalArgumentException if root is null. exception IIOInvalidTreeException if the tree cannot be parsed successfully using the rules of the given format. see #getMetadataFormatNames see #getAsTree see #mergeTree reset(); mergeTree(formatName, root);