Class X5455_ExtendedTimestamp
- java.lang.Object
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- org.apache.commons.compress.archivers.zip.X5455_ExtendedTimestamp
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
,ZipExtraField
public class X5455_ExtendedTimestamp extends java.lang.Object implements ZipExtraField, java.lang.Cloneable, java.io.Serializable
An extra field that stores additional file and directory timestamp data for zip entries. Each zip entry can include up to three timestamps (modify, access, create*). The timestamps are stored as 32 bit signed integers representing seconds since UNIX epoch (Jan 1st, 1970, UTC). This field improves on zip's default timestamp granularity, since it allows one to store additional timestamps, and, in addition, the timestamps are stored using per-second granularity (zip's default behavior can only store timestamps to the nearest even second).
Unfortunately, 32 (signed) bits can only store dates up to the year 2037, and so this extra field will eventually be obsolete. Enjoy it while it lasts!
- modifyTime: most recent time of file/directory modification (or file/dir creation if the entry has not been modified since it was created).
- accessTime: most recent time file/directory was opened (e.g., read from disk). Many people disable their operating systems from updating this value using the NOATIME mount option to optimize disk behavior, and thus it's not always reliable. In those cases it's always equal to modifyTime.
- *createTime: modern linux file systems (e.g., ext2 and newer) do not appear to store a value like this, and so it's usually omitted altogether in the zip extra field. Perhaps other unix systems track this.
We're using the field definition given in Info-Zip's source archive: zip-3.0.tar.gz/proginfo/extrafld.txt
Value Size Description ----- ---- ----------- 0x5455 Short tag for this extra block type ("UT") TSize Short total data size for this block Flags Byte info bits (ModTime) Long time of last modification (UTC/GMT) (AcTime) Long time of last access (UTC/GMT) (CrTime) Long time of original creation (UTC/GMT) Central-header version: Value Size Description ----- ---- ----------- 0x5455 Short tag for this extra block type ("UT") TSize Short total data size for this block Flags Byte info bits (refers to local header!) (ModTime) Long time of last modification (UTC/GMT)
- Since:
- 1.5
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static byte
ACCESS_TIME_BIT
The bit set inside the flags by when the lasr access time is present in this extra field.static byte
CREATE_TIME_BIT
The bit set inside the flags by when the original creation time is present in this extra field.static byte
MODIFY_TIME_BIT
The bit set inside the flags by when the last modification time is present in this extra field.-
Fields inherited from interface org.apache.commons.compress.archivers.zip.ZipExtraField
EXTRAFIELD_HEADER_SIZE
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Constructor Summary
Constructors Constructor Description X5455_ExtendedTimestamp()
Constructor for X5455_ExtendedTimestamp.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
clone()
boolean
equals(java.lang.Object o)
java.util.Date
getAccessJavaTime()
Returns the access time as a java.util.Date of this zip entry, or null if no such timestamp exists in the zip entry.ZipLong
getAccessTime()
Returns the access time (seconds since epoch) of this zip entry as a ZipLong object, or null if no such timestamp exists in the zip entry.byte[]
getCentralDirectoryData()
The actual data to put into central directory data - without Header-ID or length specifier.ZipShort
getCentralDirectoryLength()
Length of the extra field in the local file data - without Header-ID or length specifier.java.util.Date
getCreateJavaTime()
Returns the create time as a a java.util.Date of this zip entry, or null if no such timestamp exists in the zip entry.ZipLong
getCreateTime()
Returns the create time (seconds since epoch) of this zip entry as a ZipLong object, or null if no such timestamp exists in the zip entry.byte
getFlags()
Gets flags byte.ZipShort
getHeaderId()
The Header-ID.byte[]
getLocalFileDataData()
The actual data to put into local file data - without Header-ID or length specifier.ZipShort
getLocalFileDataLength()
Length of the extra field in the local file data - without Header-ID or length specifier.java.util.Date
getModifyJavaTime()
Returns the modify time as a java.util.Date of this zip entry, or null if no such timestamp exists in the zip entry.ZipLong
getModifyTime()
Returns the modify time (seconds since epoch) of this zip entry as a ZipLong object, or null if no such timestamp exists in the zip entry.int
hashCode()
boolean
isBit0_modifyTimePresent()
Returns whether bit0 of the flags byte is set or not, which should correspond to the presence or absence of a modify timestamp in this particular zip entry.boolean
isBit1_accessTimePresent()
Returns whether bit1 of the flags byte is set or not, which should correspond to the presence or absence of a "last access" timestamp in this particular zip entry.boolean
isBit2_createTimePresent()
Returns whether bit2 of the flags byte is set or not, which should correspond to the presence or absence of a create timestamp in this particular zip entry.void
parseFromCentralDirectoryData(byte[] buffer, int offset, int length)
Doesn't do anything special since this class always uses the same parsing logic for both central directory and local file data.void
parseFromLocalFileData(byte[] data, int offset, int length)
Populate data from this array as if it was in local file data.void
setAccessJavaTime(java.util.Date d)
Sets the access time as a java.util.Date of this zip entry.void
setAccessTime(ZipLong l)
Sets the access time (seconds since epoch) of this zip entry using a ZipLong objectvoid
setCreateJavaTime(java.util.Date d)
Sets the create time as a java.util.Date of this zip entry.void
setCreateTime(ZipLong l)
Sets the create time (seconds since epoch) of this zip entry using a ZipLong objectvoid
setFlags(byte flags)
Sets flags byte.void
setModifyJavaTime(java.util.Date d)
Sets the modify time as a java.util.Date of this zip entry.void
setModifyTime(ZipLong l)
Sets the modify time (seconds since epoch) of this zip entry using a ZipLong object.java.lang.String
toString()
Returns a String representation of this class useful for debugging purposes.
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Field Detail
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MODIFY_TIME_BIT
public static final byte MODIFY_TIME_BIT
The bit set inside the flags by when the last modification time is present in this extra field.- See Also:
- Constant Field Values
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ACCESS_TIME_BIT
public static final byte ACCESS_TIME_BIT
The bit set inside the flags by when the lasr access time is present in this extra field.- See Also:
- Constant Field Values
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CREATE_TIME_BIT
public static final byte CREATE_TIME_BIT
The bit set inside the flags by when the original creation time is present in this extra field.- See Also:
- Constant Field Values
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Method Detail
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getHeaderId
public ZipShort getHeaderId()
The Header-ID.- Specified by:
getHeaderId
in interfaceZipExtraField
- Returns:
- the value for the header id for this extrafield
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getLocalFileDataLength
public ZipShort getLocalFileDataLength()
Length of the extra field in the local file data - without Header-ID or length specifier.- Specified by:
getLocalFileDataLength
in interfaceZipExtraField
- Returns:
- a
ZipShort
for the length of the data of this extra field
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getCentralDirectoryLength
public ZipShort getCentralDirectoryLength()
Length of the extra field in the local file data - without Header-ID or length specifier.For X5455 the central length is often smaller than the local length, because central cannot contain access or create timestamps.
- Specified by:
getCentralDirectoryLength
in interfaceZipExtraField
- Returns:
- a
ZipShort
for the length of the data of this extra field
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getLocalFileDataData
public byte[] getLocalFileDataData()
The actual data to put into local file data - without Header-ID or length specifier.- Specified by:
getLocalFileDataData
in interfaceZipExtraField
- Returns:
- get the data
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getCentralDirectoryData
public byte[] getCentralDirectoryData()
The actual data to put into central directory data - without Header-ID or length specifier.- Specified by:
getCentralDirectoryData
in interfaceZipExtraField
- Returns:
- the central directory data
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parseFromLocalFileData
public void parseFromLocalFileData(byte[] data, int offset, int length) throws java.util.zip.ZipException
Populate data from this array as if it was in local file data.- Specified by:
parseFromLocalFileData
in interfaceZipExtraField
- Parameters:
data
- an array of bytesoffset
- the start offsetlength
- the number of bytes in the array from offset- Throws:
java.util.zip.ZipException
- on error
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parseFromCentralDirectoryData
public void parseFromCentralDirectoryData(byte[] buffer, int offset, int length) throws java.util.zip.ZipException
Doesn't do anything special since this class always uses the same parsing logic for both central directory and local file data.- Specified by:
parseFromCentralDirectoryData
in interfaceZipExtraField
- Parameters:
buffer
- the buffer to read data fromoffset
- offset into buffer to read datalength
- the length of data- Throws:
java.util.zip.ZipException
- on error
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setFlags
public void setFlags(byte flags)
Sets flags byte. The flags byte tells us which of the three datestamp fields are present in the data:bit0 - modify time bit1 - access time bit2 - create time
Only first 3 bits of flags are used according to the latest version of the spec (December 2012).- Parameters:
flags
- flags byte indicating which of the three datestamp fields are present.
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getFlags
public byte getFlags()
Gets flags byte. The flags byte tells us which of the three datestamp fields are present in the data:bit0 - modify time bit1 - access time bit2 - create time
Only first 3 bits of flags are used according to the latest version of the spec (December 2012).- Returns:
- flags byte indicating which of the three datestamp fields are present.
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isBit0_modifyTimePresent
public boolean isBit0_modifyTimePresent()
Returns whether bit0 of the flags byte is set or not, which should correspond to the presence or absence of a modify timestamp in this particular zip entry.- Returns:
- true if bit0 of the flags byte is set.
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isBit1_accessTimePresent
public boolean isBit1_accessTimePresent()
Returns whether bit1 of the flags byte is set or not, which should correspond to the presence or absence of a "last access" timestamp in this particular zip entry.- Returns:
- true if bit1 of the flags byte is set.
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isBit2_createTimePresent
public boolean isBit2_createTimePresent()
Returns whether bit2 of the flags byte is set or not, which should correspond to the presence or absence of a create timestamp in this particular zip entry.- Returns:
- true if bit2 of the flags byte is set.
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getModifyTime
public ZipLong getModifyTime()
Returns the modify time (seconds since epoch) of this zip entry as a ZipLong object, or null if no such timestamp exists in the zip entry.- Returns:
- modify time (seconds since epoch) or null.
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getAccessTime
public ZipLong getAccessTime()
Returns the access time (seconds since epoch) of this zip entry as a ZipLong object, or null if no such timestamp exists in the zip entry.- Returns:
- access time (seconds since epoch) or null.
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getCreateTime
public ZipLong getCreateTime()
Returns the create time (seconds since epoch) of this zip entry as a ZipLong object, or null if no such timestamp exists in the zip entry.
Note: modern linux file systems (e.g., ext2) do not appear to store a "create time" value, and so it's usually omitted altogether in the zip extra field. Perhaps other unix systems track this.
- Returns:
- create time (seconds since epoch) or null.
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getModifyJavaTime
public java.util.Date getModifyJavaTime()
Returns the modify time as a java.util.Date of this zip entry, or null if no such timestamp exists in the zip entry. The milliseconds are always zeroed out, since the underlying data offers only per-second precision.- Returns:
- modify time as java.util.Date or null.
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getAccessJavaTime
public java.util.Date getAccessJavaTime()
Returns the access time as a java.util.Date of this zip entry, or null if no such timestamp exists in the zip entry. The milliseconds are always zeroed out, since the underlying data offers only per-second precision.- Returns:
- access time as java.util.Date or null.
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getCreateJavaTime
public java.util.Date getCreateJavaTime()
Returns the create time as a a java.util.Date of this zip entry, or null if no such timestamp exists in the zip entry. The milliseconds are always zeroed out, since the underlying data offers only per-second precision.
Note: modern linux file systems (e.g., ext2) do not appear to store a "create time" value, and so it's usually omitted altogether in the zip extra field. Perhaps other unix systems track this.
- Returns:
- create time as java.util.Date or null.
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setModifyTime
public void setModifyTime(ZipLong l)
Sets the modify time (seconds since epoch) of this zip entry using a ZipLong object.
Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the flags is also set.
- Parameters:
l
- ZipLong of the modify time (seconds per epoch)
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setAccessTime
public void setAccessTime(ZipLong l)
Sets the access time (seconds since epoch) of this zip entry using a ZipLong object
Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the flags is also set.
- Parameters:
l
- ZipLong of the access time (seconds per epoch)
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setCreateTime
public void setCreateTime(ZipLong l)
Sets the create time (seconds since epoch) of this zip entry using a ZipLong object
Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the flags is also set.
- Parameters:
l
- ZipLong of the create time (seconds per epoch)
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setModifyJavaTime
public void setModifyJavaTime(java.util.Date d)
Sets the modify time as a java.util.Date of this zip entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the flags is also set.
- Parameters:
d
- modify time as java.util.Date
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setAccessJavaTime
public void setAccessJavaTime(java.util.Date d)
Sets the access time as a java.util.Date of this zip entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the flags is also set.
- Parameters:
d
- access time as java.util.Date
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setCreateJavaTime
public void setCreateJavaTime(java.util.Date d)
Sets the create time as a java.util.Date of this zip entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the flags is also set.
- Parameters:
d
- create time as java.util.Date
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toString
public java.lang.String toString()
Returns a String representation of this class useful for debugging purposes.- Overrides:
toString
in classjava.lang.Object
- Returns:
- A String representation of this class useful for debugging purposes.
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clone
public java.lang.Object clone() throws java.lang.CloneNotSupportedException
- Throws:
java.lang.CloneNotSupportedException
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equals
public boolean equals(java.lang.Object o)
- Overrides:
equals
in classjava.lang.Object
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hashCode
public int hashCode()
- Overrides:
hashCode
in classjava.lang.Object
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