Interface ContentReader
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- All Superinterfaces:
ContentAccessor
- All Known Subinterfaces:
FileContentReader
@AlfrescoPublicApi public interface ContentReader extends ContentAccessor
Represents a handle to read specific content. Content may only be accessed once per instance.Implementations of this interface might be
Serializable
but client code could should check suitability before attempting to serialize it.Implementations that are able to provide inter-VM streaming, such as accessing WebDAV, would be
Serializable
. An accessor that has to access a local file on the server could not provide inter-VM streaming unless it specifically makes remote calls and opens sockets, etc.- Author:
- Derek Hulley
- See Also:
ContentWriter
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
exists()
Check if theunderlying content
is present.void
getContent(java.io.File file)
Gets content from the repository direct to filevoid
getContent(java.io.OutputStream os)
Gets content from the repository.java.io.InputStream
getContentInputStream()
Get a stream to read from the underlying channeljava.lang.String
getContentString()
Gets content from the repository direct toString
.java.lang.String
getContentString(int length)
Gets content from the repository direct toString
, but limiting the string size to a given number of characters.java.nio.channels.FileChannel
getFileChannel()
Provides read-only, random-access to the underlying content.long
getLastModified()
Gets the time of the last modification of the underlying content.java.nio.channels.ReadableByteChannel
getReadableChannel()
Provides low-level access to the underlying content.ContentReader
getReader()
Convenience method to get another reader onto the underlying content.boolean
isClosed()
Convenience method to find out if this reader has been closed.-
Methods inherited from interface org.alfresco.service.cmr.repository.ContentAccessor
addListener, getContentData, getContentUrl, getEncoding, getLocale, getMimetype, getSize, isChannelOpen, setEncoding, setLocale, setMimetype
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Method Detail
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getReader
ContentReader getReader() throws ContentIOException
Convenience method to get another reader onto the underlying content.- Returns:
- Returns a reader onto the underlying content
- Throws:
ContentIOException
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exists
boolean exists()
Check if theunderlying content
is present.- Returns:
- Returns true if there is content at the URL refered to by this reader
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getLastModified
long getLastModified()
Gets the time of the last modification of the underlying content.- Returns:
- Returns the last modification time using the standard long
time, or
0L
if the content doesn'texist
. - See Also:
System.currentTimeMillis()
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isClosed
boolean isClosed()
Convenience method to find out if this reader has been closed. Once closed, the content can no longer be read. This method could be used to wait for a particular read operation to complete, for example.- Returns:
- Return true if the content input stream has been used and closed otherwise false.
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getReadableChannel
java.nio.channels.ReadableByteChannel getReadableChannel() throws ContentIOException
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:
- Returns a stream that can be read at will, but must be closed when completed
- Throws:
ContentIOException
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getFileChannel
java.nio.channels.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,getReadableChannel()
.- Returns:
- Returns a random-access channel onto the content
- Throws:
ContentIOException
- See Also:
getReadableChannel()
,RandomAccessFile.getChannel()
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getContentInputStream
java.io.InputStream getContentInputStream() throws ContentIOException
Get a stream to read from the underlying channel- Returns:
- Returns an input stream onto the underlying channel
- Throws:
ContentIOException
- See Also:
getReadableChannel()
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getContent
void getContent(java.io.OutputStream os) throws ContentIOException
Gets content from the repository.All resources will be closed automatically.
Care must be taken that the bytes read from the stream are properly decoded according to the
encoding
property.- Parameters:
os
- the stream to which to write the content- Throws:
ContentIOException
- See Also:
getReadableChannel()
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getContent
void getContent(java.io.File file) throws ContentIOException
Gets content from the repository direct to fileAll resources will be closed automatically.
- Parameters:
file
- the file to write the content to - it will be overwritten- Throws:
ContentIOException
- See Also:
getContentInputStream()
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getContentString
java.lang.String getContentString() throws ContentIOException
Gets content from the repository direct toString
.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.
WARNING: This should only be used when the size of the content is known in advance.
- Returns:
- Returns a String representation of the content
- Throws:
ContentIOException
- See Also:
getContentString(int)
,getContentInputStream()
,String(byte[])
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getContentString
java.lang.String getContentString(int length) throws ContentIOException
Gets content from the repository direct toString
, 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.
- Parameters:
length
- the maximum number of characters to retrieve- Returns:
- Returns a truncated String representation of the content
- Throws:
ContentIOException
java.lang.IllegalArgumentException
- if the length is < 0 or >Integer.MAX_VALUE
- See Also:
getContentString()
,getContentInputStream()
,String(byte[])
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