ZipCrc Java Reference Documentation

CkZipCrc

Current Version: 11.1.0

Requires Chilkat Bundle License

Calculate a Zip CRC checksum for a file or in-memory data.

Object Creation

CkZipCrc obj = new CkZipCrc();

Properties

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.

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.

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

BeginStream

void BeginStream();

Provides a way to calculate a CRC by streaming the data a chunk at a time. An application would start by calling BeginStream. Then it would add data by calling MoreData for each additional chunk. After the last chunk has been processed, the EndStream method is called to return the CRC.

CrcBd

int CrcBd(CkBinData bd);

Introduced in version 9.5.0.75

Calculates a CRC32 for the bytes contained in bd.

CrcSb

int CrcSb(CkStringBuilder sb, String charset);

Introduced in version 9.5.0.75

Calculates a CRC32 for the string contained in sb. The charset is the byte representation to be used for the sb when calculating the CRC32. It can be utf-8, utf-16, windows-1252, iso-8859-1, or any of the character encodings (charsets) listed at the link below.

CrcString

int CrcString(String str, String charset);

Introduced in version 9.5.0.75

Calculates a CRC32 for a string. The charset is the byte representation to be used for the str when calculating the CRC32. It can be utf-8, utf-16, windows-1252, iso-8859-1, or any of the character encodings (charsets) listed at the link below.

EndStream

int EndStream();

Finalizes and returns the Zip CRC value calculated by calling BeginStream followed by multiple calls to MoreData.

FileCrc

int FileCrc(String path);

Calculates the CRC32 of a file. The data contained in the file is streamed for the calculation to keep the memory footprint small and constant. Returns the CRC32 of the file.

More Information and Examples

(Android™) Compute CRC32 of a File (Java) Compute CRC32 of a File

FileCrcAsync ^{(Android™) (Java)}

CkTask FileCrcAsync(String path);

Creates an asynchronous task to call the FileCrc 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 the caller of the task's async method.

Returns true for success, false for failure.

ToHex

boolean ToHex(int crc, CkString outStr);
String toHex(int crc);

Converts a 32-bit integer to a hex string.

Returns true for success, false for 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 zipcrcProgress = new MyBaseProgress();
http.put_EventCallbackObject(zipcrcProgress);

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.

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

CalculateCrc Deprecated

int CalculateCrc(CkByteData data);

Calculates a 32-bit CRC for in-memory byte data. This is the 32-bit CRC that would be found in a Zip file header if a file containing the data was added to a zip archive. Returns the CRC32 of the data.

MoreData Deprecated

void MoreData(CkByteData data);

Adds additional data to the CRC currently being calculated. (See BeginStream for more information.)