org.apache.tomcat.util.http

Class MimeHeaders

public class MimeHeaders extends Object

Memory-efficient repository for Mime Headers. When the object is recycled, it will keep the allocated headers[] and all the MimeHeaderField - no GC is generated. For input headers it is possible to use the MessageByte for Fileds - so no GC will be generated. The only garbage is generated when using the String for header names/values - this can't be avoided when the servlet calls header methods, but is easy to avoid inside tomcat. The goal is to use _only_ MessageByte-based Fields, and reduce to 0 the memory overhead of tomcat. TODO: XXX one-buffer parsing - for http ( other protocols don't need that ) XXX remove unused methods XXX External enumerations, with 0 GC. XXX use HeaderName ID

Author: dac@eng.sun.com James Todd [gonzo@eng.sun.com] Costin Manolache kevin seguin

Field Summary
static intDEFAULT_HEADER_SIZE
Initial size - should be == average number of headers per request XXX make it configurable ( fine-tuning of web-apps )
Constructor Summary
MimeHeaders()
Creates a new MimeHeaders object using a default buffer size.
Method Summary
MessageBytesaddValue(String name)
Create a new named header , return the MessageBytes container for the new value
MessageBytesaddValue(byte[] b, int startN, int len)
Create a new named header using un-translated byte[].
MessageBytesaddValue(char[] c, int startN, int len)
Create a new named header using translated char[].
voidclear()
Clears all header fields.
intfindHeader(String name, int starting)
Find the index of a header with the given name.
StringgetHeader(String name)
MessageBytesgetName(int n)
Returns the Nth header name, or null if there is no such header.
MessageBytesgetUniqueValue(String name)
Finds and returns a unique header field with the given name.
MessageBytesgetValue(int n)
Returns the Nth header value, or null if there is no such header.
MessageBytesgetValue(String name)
Finds and returns a header field with the given name.
Enumerationnames()
Returns an enumeration of strings representing the header field names.
voidrecycle()
Clears all header fields.
voidremoveHeader(String name)
Removes a header field with the specified name.
MessageBytessetValue(String name)
Allow "set" operations - return a MessageBytes container for the header value ( existing header or new if this .
intsize()
Returns the current number of header fields.
StringtoString()
EXPENSIVE!
Enumerationvalues(String name)

Field Detail

DEFAULT_HEADER_SIZE

public static final int DEFAULT_HEADER_SIZE
Initial size - should be == average number of headers per request XXX make it configurable ( fine-tuning of web-apps )

Constructor Detail

MimeHeaders

public MimeHeaders()
Creates a new MimeHeaders object using a default buffer size.

Method Detail

addValue

public MessageBytes addValue(String name)
Create a new named header , return the MessageBytes container for the new value

addValue

public MessageBytes addValue(byte[] b, int startN, int len)
Create a new named header using un-translated byte[]. The conversion to chars can be delayed until encoding is known.

addValue

public MessageBytes addValue(char[] c, int startN, int len)
Create a new named header using translated char[].

clear

public void clear()
Clears all header fields.

findHeader

public int findHeader(String name, int starting)
Find the index of a header with the given name.

getHeader

public String getHeader(String name)

getName

public MessageBytes getName(int n)
Returns the Nth header name, or null if there is no such header. This may be used to iterate through all header fields.

getUniqueValue

public MessageBytes getUniqueValue(String name)
Finds and returns a unique header field with the given name. If no such field exists, null is returned. If the specified header field is not unique then an IllegalArgumentException is thrown.

getValue

public MessageBytes getValue(int n)
Returns the Nth header value, or null if there is no such header. This may be used to iterate through all header fields.

getValue

public MessageBytes getValue(String name)
Finds and returns a header field with the given name. If no such field exists, null is returned. If more than one such field is in the header, an arbitrary one is returned.

names

public Enumeration names()
Returns an enumeration of strings representing the header field names. Field names may appear multiple times in this enumeration, indicating that multiple fields with that name exist in this header.

recycle

public void recycle()
Clears all header fields.

removeHeader

public void removeHeader(String name)
Removes a header field with the specified name. Does nothing if such a field could not be found.

Parameters: name the name of the header field to be removed

setValue

public MessageBytes setValue(String name)
Allow "set" operations - return a MessageBytes container for the header value ( existing header or new if this .

size

public int size()
Returns the current number of header fields.

toString

public String toString()
EXPENSIVE!!! only for debugging.

values

public Enumeration values(String name)
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