Class MimeHeaders
StringMap
class and
provides added methods that are of help when manipulating MIME headers.
By creating an instance of this class, the user can conveniently read,
write, and modify MIME headers.- Version:
- 2.4
- Author:
- Colin Stevens (colin.stevens@sun.com)
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionCreates a new, emptyMimeHeaders
object.Creates a newMimeHeaders
object and then initializes it by reading MIME headers from the specified input stream. -
Method Summary
Modifier and TypeMethodDescriptionvoid
Adds a mapping for the given case-insensitive key to the specified value in thisMimeHeaders
object.void
copyTo
(MimeHeaders other) Copies the contents of thisMimeHeaders
object,adding
all the other's keys and values to the other.void
print
(OutputStream out) Writes thisMimeHeaders
object to the given output stream.void
print
(PrintStream out) Writes thisMimeHeaders
object to the given output stream.void
Maps the given case-insensitive key to the specified value in thisMimeHeaders
object, replacing the old value.void
putIfNotPresent
(String key, String value) Maps the given case-insensitive key to the specified value if the key does not already exist in thisMimeHeaders
object.void
read
(HttpInputStream in) Reads MIME headers from the specified input stream.void
read
(HttpInputStream in, boolean shouldReplace) Reads MIME headers from the specified input stream.
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Field Details
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MAX_LINE
public static final int MAX_LINE- See Also:
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MAX_LINES
public static final int MAX_LINES- See Also:
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Constructor Details
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MimeHeaders
public MimeHeaders()Creates a new, emptyMimeHeaders
object. -
MimeHeaders
Creates a newMimeHeaders
object and then initializes it by reading MIME headers from the specified input stream.- Parameters:
in
- The input stream to read.- Throws:
IOException
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Method Details
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read
Reads MIME headers from the specified input stream. This method reads up to and consumes the blank line that marks the end of the MIME headers. It also stops reading if it reaches the end of the input stream.The MIME headers read from the input stream are stored in this
MimeHeaders
object. All headers read are added to the existing headers; the new headers do not replace the existing ones. The order of the headers in this object will reflect the order of the headers from the input stream, but space characters surrounding the keys and values are not preserved.In a set of MIME headers, the given key may appear multiple times (that is, on multiple lines, not necessarily consecutively). In that case, that key will appear multiple times in this
MimeHeaders
object also. The HTTP spec says that if a given key appears multiple times in a set of MIME headers, the values can be concatenated together with commas between them. However, in practice, it appears that some browsers and HTTP servers get confused when encountering such collapsed MIME headers, for instance, the Yahoo mail reader program.MIME headers also support the idea of continuation lines, where a key (and optionally its value) is followed on subsequent line(s) by another value without a key. The HTTP spec says that in this case the values can be concatenated together with space characters between them. In practice, joining continuation lines together does not seem to confuse any browsers or HTTP servers. This method joins continuation lines together by putting the space-equivalent characters "\r\n\t" between the values so it can be easily parsed with
StringTokenizer
and also easily written to an output stream in a format that actually preserves its formatting as a continuation line.- Parameters:
in
- The input stream to read from.- Throws:
IOException
- if the input stream throws an IOException while being read.
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read
Reads MIME headers from the specified input stream. Same as (@link #read(HttpInputStream in)), only existing keys may be replaced or augmented.- Parameters:
in
- The input stream to read from.shouldReplace
- If true, existing keys are replaced instead of augmented.- Throws:
IOException
- if the input stream throws an IOException while being read.- See Also:
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print
Writes thisMimeHeaders
object to the given output stream. This method doesnot
write a blank line after the headers are written.- Parameters:
out
- The output stream.
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print
Writes thisMimeHeaders
object to the given output stream. This method doesnot
write a blank line after the headers are written.- Parameters:
out
- The output stream.
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putIfNotPresent
Maps the given case-insensitive key to the specified value if the key does not already exist in thisMimeHeaders
object.Often, when dealing with MIME headers, the user will want to set a header only if that header is not already set.
- Parameters:
key
- The new key. May not benull
.value
- The new value. May benull
.
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put
Maps the given case-insensitive key to the specified value in thisMimeHeaders
object, replacing the old value.This is convenience method that automatically converts the integer value to a string before calling the underlying
put
method.- Parameters:
key
- The new key. May not benull
.value
- The new value.
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add
Adds a mapping for the given case-insensitive key to the specified value in thisMimeHeaders
object. It leaves any existing key-value mapping alone.This is convenience method that automatically converts the integer value to a string before calling the underlying
add
method.- Parameters:
key
- The new key. May not benull
.value
- The new value.
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copyTo
Copies the contents of thisMimeHeaders
object,adding
all the other's keys and values to the other.- Parameters:
other
- TheMimeHeaders
object to copy to.
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