Package org.eclipse.core.runtime.content

Interface IContentDescriber

All Known Subinterfaces:

ITextContentDescriber

All Known Implementing Classes:

BinarySignatureDescriber, org.eclipse.core.internal.content.TextContentDescriber, XMLContentDescriber, XMLRootElementContentDescriber, XMLRootElementContentDescriber2

public interface IContentDescriber

Content describers know how to retrieve metadata from contents.

Note: It is expected that content describer implementations be declared in a package that is exempt from plug-in activation (using the Eclipse-AutoStart bundle manifest header). Since all describers are instantiated when the content type framework is initialized, failure in complying with this requirement causes premature activation, which must be avoided. Future implementations of the framework might refuse to instantiate describers if doing so would trigger activation of the corresponding plug-in.

Describers for text-based content types should implement ITextContentDescriber instead.

Clients may implement this interface.

Since:

3.0

See Also:

• IContentDescription

Field Summary

Fields

Modifier and Type	Field	Description
static final int	INDETERMINATE	Description result constant, indicating that it was not possible to determine whether the contents were valid for the intended content type.
static final int	INVALID	Description result constant, indicating the contents are invalid for the intended content type.
static final int	VALID	Description result constant, indicating the contents are valid for the intended content type.

Method Summary

Modifier and Type	Method	Description
int	describe(InputStream contents, IContentDescription description)	Tries to fill a description for the given contents.
QualifiedName[]	getSupportedOptions()	Returns the properties supported by this describer.

Field Details

INDETERMINATE

static final int INDETERMINATE

Description result constant, indicating that it was not possible to determine whether the contents were valid for the intended content type.

See Also:

• describe(java.io.InputStream, org.eclipse.core.runtime.content.IContentDescription)
• Constant Field Values

INVALID

static final int INVALID

Description result constant, indicating the contents are invalid for the intended content type.

See Also:

• describe(java.io.InputStream, org.eclipse.core.runtime.content.IContentDescription)
• Constant Field Values

VALID

static final int VALID

Description result constant, indicating the contents are valid for the intended content type.

See Also:

• describe(java.io.InputStream, org.eclipse.core.runtime.content.IContentDescription)
• Constant Field Values

Method Details

describe

int describe(InputStream contents,
 IContentDescription description)
      throws IOException

Tries to fill a description for the given contents. Returns an int indicating whether the given stream of bytes represents a valid sample for its corresponding content type. If no content description is provided, this method should perform content type validation.

The input stream must be kept open, and any IOExceptions while reading the stream should flow to the caller.

Parameters:

contents - the contents to be examined

description - a description to be filled in, or null if only content type validation is to be performed

Returns:

one of the following:

• VALID
• INVALID
• INDETERMINATE

Throws:

IOException - if an I/O error occurs

See Also:

• IContentDescription
• VALID
• INVALID
• INDETERMINATE

getSupportedOptions

QualifiedName[] getSupportedOptions()

Returns the properties supported by this describer.

Returns:

the supported properties

See Also:

• describe(java.io.InputStream, org.eclipse.core.runtime.content.IContentDescription)