AbstractContentReader (Alfresco 5.0.3 Public API)

org.alfresco.repo.content

Class AbstractContentReader

org.alfresco.repo.content.AbstractContentReader

All Implemented Interfaces:

Direct Known Subclasses:

public abstract class AbstractContentReader

Implements all the convenience methods of the interface. The only methods that need to be implemented, i.e. provide low-level content access are:

createReader() to read content from the repository
getDirectReadableChannel() to provide direct storage access

Constructor Summary
protected	AbstractContentReader(String contentUrl)

Method Summary
void	addListener(ContentStreamListener listener) Adds the listener after checking that the output stream isn't already in use.
protected void	channelOpened() Derived classes can call this method to ensure that necessary trace logging is performed when the IO Channel is opened.
static boolean	compareContentReaders(ContentReader left, ContentReader right) Does a comparison of the binaries associated with two readers.
protected abstract ContentReader	createReader() A factory method for subclasses to implement that will ensure the proper implementation of the ContentReader.getReader() method.
protected void	finalize()
protected FileChannel	getCallbackFileChannel(FileChannel directChannel, List<ContentStreamListener> listeners) Generate a callback instance of the FileChannel.
void	getContent(File file) Gets content from the repository direct to file
void	getContent(OutputStream os) Copies the input stream to the given `OutputStream`
ContentData	getContentData() Get the data representation of the content being accessed.
InputStream	getContentInputStream() Get a stream to read from the underlying channel
String	getContentString() Makes use of the encoding, if available, to convert bytes to a string.
String	getContentString(int length) Gets content from the repository direct to `String`, but limiting the string size to a given number of characters.
String	getContentUrl() Retrieve the URL that this accessor references
protected abstract ReadableByteChannel	getDirectReadableChannel() Provides low-level access to read content from the repository.
String	getEncoding() Get the encoding of the content being accessed
FileChannel	getFileChannel() Provides read-only, random-access to the underlying content.
TransformationOptionLimits	getLimits()
Locale	getLocale() Get the locale of the content being accessed
String	getMimetype() Get the content mimetype
ReadableByteChannel	getReadableChannel() Provides low-level access to the underlying content.
ContentReader	getReader() Performs checks and copies required reader attributes
TransformerDebug	getTransformerDebug()
boolean	getUseBufferedInputStream()
boolean	isChannelOpen() Gets the open/close state of the underlying IO Channel.
boolean	isClosed() An automatically created listener sets the flag
protected void	setContentUrl(String contentUrl) Allow derived implementations to set the Content URL.
void	setEncoding(String encoding) Set the `String` encoding for this accessor
void	setLimits(TransformationOptionLimits limits)
void	setLocale(Locale locale) Set the `Locale` for this accessor
void	setMimetype(String mimetype) Set the mimetype that must be used for accessing the content.
void	setTransformerDebug(TransformerDebug transformerDebug)
void	setUseBufferedInputStream(boolean useBufferedInputStream)
String	toString()

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.alfresco.service.cmr.repository.ContentAccessor

getSize

Methods inherited from interface org.alfresco.service.cmr.repository.ContentReader

exists, getLastModified

AbstractContentReader

protected AbstractContentReader(String contentUrl)

contentUrl - the content URL - this should be relative to the root of the store and not absolute: to enable moving of the stores

public void setLimits(TransformationOptionLimits limits)

public TransformationOptionLimits getLimits()

public void setTransformerDebug(TransformerDebug transformerDebug)

public TransformerDebug getTransformerDebug()

setUseBufferedInputStream

public void setUseBufferedInputStream(boolean useBufferedInputStream)

getUseBufferedInputStream

public boolean getUseBufferedInputStream()

public void addListener(ContentStreamListener listener)

Adds the listener after checking that the output stream isn't already in use.

listener - a listener that will be called for output stream event notification

protected abstract ContentReader createReader()
throws ContentIOException

A factory method for subclasses to implement that will ensure the proper implementation of the ContentReader.getReader() method.

Only the instance need be constructed. The required mimetype, encoding, etc will be copied across by this class.

Returns a reader onto the location referenced by this instance. The instance must always be a new instance.

public final ContentReader getReader()
throws ContentIOException

Performs checks and copies required reader attributes

Returns a reader onto the underlying content

public final boolean isClosed()

An automatically created listener sets the flag

isClosed in interface ContentReader

Return true if the content input stream has been used and closed otherwise false.

public boolean isChannelOpen()

Description copied from interface: ContentAccessor

Gets the open/close state of the underlying IO Channel.

Returns true if the underlying IO Channel is open

getDirectReadableChannel

protected abstract ReadableByteChannel getDirectReadableChannel()
throws ContentIOException

Provides low-level access to read content from the repository.

This is the only of the content reading methods that needs to be implemented by derived classes. All other content access methods make use of this in their underlying implementations.

Returns a channel from which content can be read

ContentIOException - if the channel could not be opened or the underlying content has disappeared

public final ReadableByteChannel getReadableChannel()
throws ContentIOException

Description copied from interface: ContentReader

Provides low-level access to the underlying content.

Once the stream is provided to a client it should remain active (subject to any timeouts) until closed by the client.

Returns a stream that can be read at will, but must be closed when completed

getDirectReadableChannel(), getCallbackReadableChannel(ReadableByteChannel, List)

public FileChannel getFileChannel()
throws ContentIOException

Provides read-only, random-access to the underlying content. In general, this method should be considered more expensive than the sequential-access method, ContentReader.getReadableChannel().

Returns a random-access channel onto the content

getContentInputStream

public InputStream getContentInputStream()
throws ContentIOException

Description copied from interface: ContentReader

Get a stream to read from the underlying channel

Returns an input stream onto the underlying channel

public final void getContent(OutputStream os)
throws ContentIOException

Copies the input stream to the given OutputStream

os - the stream to which to write the content

public final void getContent(File file)
throws ContentIOException

Description copied from interface: ContentReader

Gets content from the repository direct to file

All resources will be closed automatically.

file - the file to write the content to - it will be overwritten

public final String getContentString(int length)
throws ContentIOException

Description copied from interface: ContentReader

Gets content from the repository direct to String, but limiting the string size to a given number of characters.

If the encoding is known then it will be used otherwise the default system byte[] to String conversion will be used.

All resources will be closed automatically.

length - the maximum number of characters to retrieve

Returns a truncated String representation of the content

public final String getContentString()
throws ContentIOException

Makes use of the encoding, if available, to convert bytes to a string.

All the content is streamed into memory. So, like the interface said, be careful with this method.

Returns a String representation of the content

compareContentReaders

public static boolean compareContentReaders(ContentReader left,
ContentReader right)
throws ContentIOException

Does a comparison of the binaries associated with two readers. Several shortcuts are assumed to be valid:
- if the readers are the same instance, then the binaries are the same
- if the size field is different, then the binaries are different
Otherwise the binaries are compared.

Returns true if the underlying binaries are the same

protected void finalize()
throws Throwable

finalize in class Object

public String toString()

toString in class Object

public ContentData getContentData()

Description copied from interface: ContentAccessor

Get the data representation of the content being accessed.

The content mimetype must be set before this method is called as the content data requires a mimetype whenever the content URL is specified.

Returns the content data

protected final void channelOpened()

Derived classes can call this method to ensure that necessary trace logging is performed when the IO Channel is opened.

public String getContentUrl()

Description copied from interface: ContentAccessor

Retrieve the URL that this accessor references

protected void setContentUrl(String contentUrl)

Allow derived implementations to set the Content URL. This allows for implementations where the URL is not known when the accessor is first constructed.

contentUrl - the new content URL

public String getMimetype()

Description copied from interface: ContentAccessor

Get the content mimetype

Returns a content mimetype

public void setMimetype(String mimetype)

Description copied from interface: ContentAccessor

Set the mimetype that must be used for accessing the content.

When dealing with a ContentWriter, you may wish to use ContentWriter.guessMimetype(String) to have this set for you based on the filename and contents.

mimetype - the underlying content's mimetype - null if unknown

public String getEncoding()

Description copied from interface: ContentAccessor

Get the encoding of the content being accessed

Returns the content encoding - null if unknown

public void setEncoding(String encoding)

Description copied from interface: ContentAccessor

Set the String encoding for this accessor

When dealing with a ContentWriter, you may wish to use ContentWriter.guessMimetype(String) to have this set for you based on the contents.

encoding - the underlying content's encoding - null if unknown

public Locale getLocale()

Description copied from interface: ContentAccessor

Get the locale of the content being accessed

Returns the content locale or null if unkown

public void setLocale(Locale locale)

Description copied from interface: ContentAccessor

Set the Locale for this accessor

locale - the content's locale, if known.

getCallbackFileChannel

protected FileChannel getCallbackFileChannel(FileChannel directChannel,
List<ContentStreamListener> listeners)
throws ContentIOException

Generate a callback instance of the FileChannel.

directChannel - the delegate that to perform the actual operations

listeners - the listeners to call

Returns a new channel that functions just like the original, except that it issues callbacks to the listeners

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