Bz2 Java Reference Documentation

CkBz2

Current Version: 11.5.0

Requires Chilkat Bundle License

Chilkat.Bz2 provides BZip2 compression and decompression for files, memory buffers, and BinData. It can create standard .bz2 file images, decompress .bz2 content back to its original bytes, and support abortable long-running operations.

For an extended overview, see Bz2 Class Overview

Object Creation

CkBz2 obj = new CkBz2();

Properties

AbortCurrent

boolean get_AbortCurrent();
void put_AbortCurrent(boolean newVal);

Introduced in version 9.5.0.58

Set this property to true to request cancellation of the compression or decompression operation currently executing on this object. Long-running operations check the request periodically; an operation that finishes quickly may complete before the request is observed.

A synchronous call can be cancelled by setting this property from another thread. After cancellation is processed, Chilkat resets the property to false. If no operation is running, a previously set value is cleared when the next method begins.

Cancellation is cooperative: Setting this property requests an abort; it does not guarantee immediate termination. Check the method's return value and LastErrorText to determine the final outcome.

DebugLogFilePath

void get_DebugLogFilePath(CkString str);
String debugLogFilePath();
void put_DebugLogFilePath(String newVal);

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

A timeout property set to 0, indicating an infinite timeout.
A hang occurring within an event callback in the application code.
An internal bug in the Chilkat code causing the hang.

More Information and Examples

(Android™) Example showing how to use DebugLogFilePath.(Java) Example showing how to use DebugLogFilePath.

HeartbeatMs

int get_HeartbeatMs();
void put_HeartbeatMs(int newVal);

Specifies the interval, in milliseconds, between AbortCheck event callbacks during supported long-running compression and decompression operations. The default is 0, which disables AbortCheck callbacks.

Set a positive value, such as 200, when the application needs periodic opportunities to request cancellation. The interval is approximate; callbacks occur only while an operation is at a point where progress events can be delivered.

Cancellation workflow: In an AbortCheck handler, set the callback's abort value to request termination. A synchronous method may also be cancelled from another thread by setting AbortCurrent to true.

More Information and Examples

Event Callback Examples

LastErrorHtml

void get_LastErrorHtml(CkString str);
String lastErrorHtml();

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

LastErrorText

void get_LastErrorText(CkString str);
String lastErrorText();

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

LastErrorXml

void get_LastErrorXml(CkString str);
String lastErrorXml();

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

LastMethodSuccess

boolean get_LastMethodSuccess();
void put_LastMethodSuccess(boolean newVal);

Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

VerboseLogging

boolean get_VerboseLogging();
void put_VerboseLogging(boolean newVal);

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version

void get_Version(CkString str);
String version();

Version of the component/library, such as "10.1.0"

More Information and Examples

(Android™) How to get the Chilkat version at runtime.(Java) How to get the Chilkat version at runtime.

Methods

CompressBd

boolean CompressBd(CkBinData bd);

Introduced in version 11.0.0

Compresses the current contents of bd in place. On success, the BinData no longer contains the original bytes; it contains the complete standard BZip2 stream that may be saved with a .bz2 extension.

In-place transformation: Preserve a copy of the original data if it is still needed after this call. A BZip2 stream contains a stream header, one or more compressed blocks with integrity checks, and an end-of-stream marker. It does not contain archive filenames or directory entries.

Returns true for success, false for failure.

CompressBdAsync ^{(Android™) (Java)}

CkTask CompressBdAsync(CkBinData bd);

Introduced in version 11.0.0

Creates an asynchronous task to call the CompressBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressFile

boolean CompressFile(String inFilename, String toPath);

Reads the file at inFilename and writes its compressed bytes as a standard BZip2 stream to the file at toPath. The output is conventionally given a .bz2 extension.

Both arguments must identify files, not directories. They may be absolute or relative paths, for example data/report.txt and data/report.txt.bz2.

BZip2 is a compressor, not an archive format: A .bz2 file represents one compressed byte stream. It does not store the original filename, directory path, timestamps, permissions, or multiple archive entries. Formats such as .tar.bz2 first combine files in a TAR archive and then compress that TAR stream with BZip2.

Returns true for success, false for failure.

More Information and Examples

(Android™) bz2 Compress File (Java) bz2 Compress File

CompressFileAsync ^{(Android™) (Java)}

CkTask CompressFileAsync(String inFilename, String toPath);

Creates an asynchronous task to call the CompressFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

LoadTaskCaller

boolean LoadTaskCaller(CkTask task);

Introduced in version 9.5.0.80

Loads this Bz2 object with the caller state associated with the asynchronous operation represented by task.

Advanced async infrastructure: This method is used to recover the original caller object associated with a completed task. It is not normally needed by application code. Pass a Task created by a compatible Bz2 asynchronous method; an unrelated task cannot be loaded.

Returns true for success, false for failure.

UncompressBd

boolean UncompressBd(CkBinData bd);

Introduced in version 11.0.0

Decompresses the BZip2 stream currently contained in bd in place. On success, the BinData is replaced with the original uncompressed bytes.

Input requirement: bd must contain a complete, valid BZip2 stream, such as the bytes of a .bz2 file or the output of CompressBd. This method operates on binary data and does not perform character-set conversion.

Returns true for success, false for failure.

UncompressBdAsync ^{(Android™) (Java)}

CkTask UncompressBdAsync(CkBinData bd);

Introduced in version 11.0.0

Creates an asynchronous task to call the UncompressBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressFile

boolean UncompressFile(String inFilename, String toPath);

Reads the BZip2 stream from the file at inFilename, decompresses it, and writes the original uncompressed bytes to the file at toPath.

Both arguments must identify files, not directories. Chilkat does not derive the destination name from the .bz2 filename because the BZip2 stream does not contain the original filename.

Terminology: This method decompresses BZip2 data; it does not “unzip” a ZIP archive. A .bz2 file normally contains a single compressed byte stream rather than a collection of named files.

Returns true for success, false for failure.

UncompressFileAsync ^{(Android™) (Java)}

CkTask UncompressFileAsync(String inFilename, String toPath);

Creates an asynchronous task to call the UncompressFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

Events

Chilkat supports event callbacks in Java (including Android) starting in version 9.5.0.52. To implement an event callback, your application would define and implement a class that derives from CkBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkBaseProgress base class.

For example:

// Install an event callback handler to get progress events.
MyBaseProgress bzProgress = new MyBaseProgress();
http.put_EventCallbackObject(bzProgress);

MyBaseProgress example:

import com.chilkatsoft.CkBaseProgress;
import com.chilkatsoft.CkTask;

public class MyBaseProgress extends CkBaseProgress 
{	
  public boolean AbortCheck()
  {
    System.out.println("AbortCheck");
    // Return true to abort, false to allow the method to continue.
    return false;
  }
  	
  // pctDone is a value from 0 to 100
  // (it is actually value from 0 to the PercentDoneScale property setting)
  public boolean PercentDone(int pctDone)
  {
    System.out.println(pctDone);
    // Return true to abort, false to allow the method to continue.
    // Note: A PercentDone event is the equivalent of an AbortCheck.  
    // When PercentDone events are frequently firing, AbortCheck events are suppressed.
    // AbortCheck events will fire when the time between PercentDone events is longer 
    // than the HeartbeatMs property setting.
    return false;
  }
  
  public void ProgressInfo(String name, String value)
  {
    System.out.println(name + ": " + value);
  }
  
  public void TaskCompleted(CkTask task)
  {
     System.out.println("task completed!");
  }
  
}

AbortCheck

public boolean AbortCheck();

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second. Return true to abort; return false to continue (not abort)

More Information and Examples

Chilkat Event Callback Examples

PercentDone

public boolean PercentDone(int pctDone);

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

Return true to abort; return false to continue (not abort)

More Information and Examples

Chilkat Event Callback Examples

ProgressInfo

public void ProgressInfo(String name, String value);

This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

Note: Some Chilkat methods don't fire any ProgressInfo events.

More Information and Examples

Chilkat Event Callback Examples

TaskCompleted

public void TaskCompleted(CkTask task);

Called from the background thread when an asynchronous task completes.

Deprecated

CompressFileToMem Deprecated

boolean CompressFileToMem(String inFilename, CkByteData outData);

Reads the file at inFilename, compresses it with BZip2, and returns the complete .bz2 byte stream in memory.

Returns true for success, false for failure.

CompressFileToMemAsync Deprecated ^{(Android™) (Java)}

CkTask CompressFileToMemAsync(String inFilename);

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressMemory Deprecated

boolean CompressMemory(CkByteData inData, CkByteData outData);

Compresses the bytes in inData and returns the complete standard BZip2 stream as an in-memory byte array.

Returns true for success, false for failure.

CompressMemoryAsync Deprecated ^{(Android™) (Java)}

CkTask CompressMemoryAsync(CkByteData inData);

Creates an asynchronous task to call the CompressMemory method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

CompressMemToFile Deprecated

boolean CompressMemToFile(CkByteData inData, String toPath);

Compresses the bytes in inData and writes the resulting standard BZip2 stream to the file at toPath.

Returns true for success, false for failure.

CompressMemToFileAsync Deprecated ^{(Android™) (Java)}

CkTask CompressMemToFileAsync(CkByteData inData, String toPath);

Creates an asynchronous task to call the CompressMemToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressFileToMem Deprecated

boolean UncompressFileToMem(String inFilename, CkByteData outData);

Reads and decompresses the BZip2 stream in the file at inFilename, returning the original uncompressed bytes in memory.

Returns true for success, false for failure.

UncompressFileToMemAsync Deprecated ^{(Android™) (Java)}

CkTask UncompressFileToMemAsync(String inFilename);

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressMemory Deprecated

boolean UncompressMemory(CkByteData inData, CkByteData outData);

Interprets inData as a complete BZip2 stream and returns the decompressed bytes in memory.

Returns true for success, false for failure.

UncompressMemoryAsync Deprecated ^{(Android™) (Java)}

CkTask UncompressMemoryAsync(CkByteData inData);

Creates an asynchronous task to call the UncompressMemory method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

UncompressMemToFile Deprecated

boolean UncompressMemToFile(CkByteData inData, String toPath);

Interprets inData as a complete BZip2 stream, decompresses it, and writes the original bytes to the file at toPath.

Returns true for success, false for failure.

UncompressMemToFileAsync Deprecated ^{(Android™) (Java)}

CkTask UncompressMemToFileAsync(CkByteData inData, String toPath);

Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure