ZipEntry Chilkat2 Java Reference Documentation

ZipEntry

Current Version: 11.7.0

Markdown version of this page for AI tools (v 11.7.0) · all AI docs

Chilkat.ZipEntry

Inspect, extract, update, and iterate individual entries inside a ZIP archive.

Chilkat.ZipEntry represents a single item associated with a Chilkat.Zip archive. An entry may be a file already stored in an opened ZIP, a referenced filesystem file waiting to be compressed, an in-memory text or binary entry, or a directory entry. It provides access to entry-level metadata, compressed and uncompressed data, timestamps, attributes, CRC values, encryption information, and extraction or replacement operations for that specific ZIP item.

Entry metadata

Inspect filenames, stored ZIP paths, comments, timestamps, CRC values, attributes, sizes, compression method, and compression level.

Entry type and state

Use EntryType to understand whether the entry comes from an existing ZIP, a filesystem reference, memory data, or a directory.

Extract one entry

Extract a selected file entry to disk, inflate its contents into memory, or read the uncompressed data into Chilkat objects.

Read compressed data

Access the raw compressed entry data when an application needs ZIP-level control rather than only the inflated contents.

Replace or append data

Update an entry's contents from strings, byte data, files, or in-memory data sources before writing the ZIP archive.

Iterate archive entries

Walk through entries returned from Chilkat.Zip methods to inspect, filter, extract, or modify ZIP contents one item at a time.

Common pattern: Open or create a Chilkat.Zip object, obtain a ZipEntry using methods such as EntryAt, EntryOf, EntryMatching, or FirstEntry, then inspect metadata, extract contents, update the entry, or continue iterating through the archive. Use Chilkat.Zip for whole-archive operations and ZipEntry for operations on one specific archive item.

Object Creation

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.ZipEntry;

try (ZipEntry zipEntry = new ZipEntry()) {
    // ... use zipEntry ...
} catch (ChilkatException e) {
    System.out.println(e.getMessage());          // "ZipEntry.someMethod failed: <reason>"
    System.out.println(e.getLastErrorText());    // the full log of the failed call
}
public ZipEntry()

Creates the underlying native Chilkat object. The native library (chilkat2java) is loaded the first time any Chilkat2 object is created; see the README in the download for where it is looked for (-Dchilkat2.library.path, a classpath resource, or java.library.path).

public void close()

Releases the native object (ZipEntry is AutoCloseable, so try-with-resources calls it). Calling it again does nothing; any other method or property accessor called afterwards throws IllegalStateException. An object that is never closed is freed by a background cleaner once it becomes unreachable, but the garbage collector does not see native memory, so closing is the normal path. Objects returned by methods are owned by the caller too.

public boolean isClosed()

Returns true once close() has been called.

Errors

A method that fails throws ChilkatException, an unchecked exception carrying getClassName(), getMethodName(), getReason() (one line, also in the message) and getLastErrorText() (the full log, captured at the moment of the failure). The object remains usable. Methods that look something up and find nothing return null instead of throwing (each such method says so), and methods that answer a question (hasMember, isUnlocked, ...) return a plain boolean. Property accessors do not throw for Chilkat reasons.

A null string or object argument throws NullPointerException naming the parameter (except where a method documents that null is accepted), and a string containing U+0000 throws IllegalArgumentException.

Use an object from one thread at a time; it may be handed from one thread to another. The one cross-thread operation is setting setAbortCurrent(true) on an object that is busy in another thread (on the classes that have AbortCurrent). Unlocking: call new Global().unlockBundle("...") once at startup.

Properties

Comment
// read/write
String getComment()
void setComment(String value)

Gets or sets the comment stored in the ZIP archive for this entry.

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CompressedLength
// read-only
long getCompressedLength()

The compressed size of this entry, in bytes.

For mapped entries (entries already contained within an opened ZIP archive), this property contains the actual compressed size stored within the ZIP.

For file entries or data entries that have not yet been written to a ZIP archive, compression has not yet occurred. In these cases, this property contains:

  • The current uncompressed data size for data entries.
  • The cached filesystem file size for referenced file entries.

After the ZIP archive is written, the entries become mapped entries, and this property then reflects the actual compressed size stored in the ZIP archive.

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CompressedLength64
// read-only
long getCompressedLength64()

The compressed size of this entry, in bytes, as a 64-bit integer.

For mapped entries (entries already contained within an opened ZIP archive), this property contains the actual compressed size stored within the ZIP.

For file entries or data entries that have not yet been written to a ZIP archive, compression has not yet occurred. In these cases, this property contains:

  • The current uncompressed data size for data entries.
  • The cached filesystem file size for referenced file entries.

After the ZIP archive is written, the entries become mapped entries, and this property then reflects the actual compressed size stored in the ZIP archive.

Use this property when sizes may exceed the range of a 32-bit integer.

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CompressedLengthStr
// read-only
String getCompressedLengthStr()

The compressed size of this entry as a decimal string.

For mapped entries (entries already contained within an opened ZIP archive), this property contains the actual compressed size stored within the ZIP.

For file entries or data entries that have not yet been written to a ZIP archive, compression has not yet occurred. In these cases, this property contains:

  • The current uncompressed data size for data entries.
  • The cached filesystem file size for referenced file entries.

After the ZIP archive is written, the entries become mapped entries, and this property then reflects the actual compressed size stored in the ZIP archive.

This property is useful when sizes may exceed the range of a 32-bit integer.

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CompressionLevel
// read/write
int getCompressionLevel()
void setCompressionLevel(int value)

Gets or sets the compression level for this entry.

A value of 0 means no compression, and a value of 9 means maximum compression.

The default value is 6.

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CompressionMethod
// read/write
int getCompressionMethod()
void setCompressionMethod(int value)

Gets or sets the compression method used for this entry.

  • 0 means no compression.
  • 8 means Deflate compression.

Deflate is the standard compression algorithm used by common ZIP utilities such as WinZip.

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Crc
// read-only
int getCrc()

The CRC value for this ZIP entry.

For AES-encrypted entries, the CRC value is 0.

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DebugLogFilePath
// read/write
String getDebugLogFilePath()
void setDebugLogFilePath(String value)

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
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EncryptionKeyLen
// read-only
int getEncryptionKeyLen()
Introduced in version 9.5.0.69

The AES encryption key length for this entry.

If this entry is AES encrypted, the value is 128, 192, or 256.

If this entry is not AES encrypted, the value is 0.

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EntryID
// read-only
int getEntryID()

A unique identifier assigned to this entry while the ZIP object is instantiated in memory.

This ID can be used to retrieve the same entry later with Zip.EntryById.

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EntryType
// read-only
int getEntryType()

Indicates the origin and current state of this ZIP entry.

  • 0 — Mapped Entry: an entry that already exists in an open ZIP file.
  • 1 — File Entry: a file in the local filesystem that has been referenced, but not yet read or compressed.
  • 2 — Data Entry: an entry containing uncompressed data already held in memory.
  • 3 — Null Entry: an entry that no longer exists in the ZIP archive.
  • 4 — New Directory Entry: a directory entry added to the ZIP object.

When the ZIP archive is written by calling WriteZip or WriteToMemory, entries are transformed into mapped entries. In other words, after writing, they point to compressed data contained in the newly created or rewritten ZIP archive.

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FileDateTimeStr
// read/write
String getFileDateTimeStr()
void setFileDateTimeStr(String value)

Gets or sets the local last-modified date/time for this ZIP entry in RFC 822 string format.

Example RFC 822 date/time strings:

Tue, 15 Nov 1994 12:45:26 GMT
Fri, 05 Jan 2024 18:30:00 -0500

The timezone may be specified either as a named timezone such as GMT, or as a numeric UTC offset such as -0500.

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FileName
// read/write
String getFileName()
void setFileName(String value)

Gets or sets the filename, including any relative path, stored for this entry inside the ZIP archive.

Changing this property changes the path/name that will appear in the ZIP archive. It does not rename a source file in the local filesystem.

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FileNameHex
// read-only
String getFileNameHex()

Returns the raw filename bytes found in the ZIP entry, encoded as a hexadecimal string.

This can be useful for diagnosing filename encoding issues.

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HeartbeatMs
// read/write
int getHeartbeatMs()
void setHeartbeatMs(int value)

The interval in milliseconds between each AbortCheck event callback, which enables an application to abort certain method calls before they complete. By default, HeartbeatMs is set to 0, meaning no AbortCheck event callbacks will trigger.

More Information and Examples
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IsAesEncrypted
// read-only
boolean getIsAesEncrypted()
Introduced in version 9.5.0.69

Indicates whether this ZIP entry is AES encrypted.

This property can be true only for entries already contained in a ZIP archive, such as entries obtained after calling OpenZip, OpenBd, or OpenFromMemory.

If the entry is not AES encrypted, the property is false.

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IsDirectory
// read-only
boolean getIsDirectory()

Indicates whether this ZIP entry is a directory entry.

The value is true if the entry represents a directory, and false if it represents a file.

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LastErrorHtml
// read-only
String getLastErrorHtml()

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.

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LastErrorText
// read-only
String getLastErrorText()

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.

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LastErrorXml
// read-only
String getLastErrorXml()

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.

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LastMethodSuccess
// read/write
boolean getLastMethodSuccess()
void setLastMethodSuccess(boolean value)

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.

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TextFlag
// read/write
boolean getTextFlag()
void setTextFlag(boolean value)

Gets or sets the text flag in the internal file attributes for this ZIP entry.

This flag indicates whether the entry contents should be considered text rather than binary data.

The flag is informational and does not need to be accurate for normal ZIP processing. It is provided for compatibility with applications that may be sensitive to this attribute.

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UncompressedLength
// read-only
long getUncompressedLength()

The uncompressed size of this entry, in bytes.

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UncompressedLength64
// read-only
long getUncompressedLength64()

The uncompressed size of this entry, in bytes, as a 64-bit integer.

Use this property when the uncompressed size may exceed the range of a 32-bit integer.

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UncompressedLengthStr
// read-only
String getUncompressedLengthStr()

The uncompressed size of this ZIP entry as a decimal string.

This is useful when the uncompressed size may be larger than what can safely be represented by a 32-bit integer.

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VerboseLogging
// read/write
boolean getVerboseLogging()
void setVerboseLogging(boolean value)

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.

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Version
// read-only
String getVersion()

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

More Information and Examples
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Methods

AppendString
void appendString(String strContent, String charset)

Appends text data to this ZIP entry's file contents.

The text is converted to bytes using the character encoding specified by charset, such as utf-8, utf-16, or ansi.

If this entry is already a Data Entry (EntryType = 2), then the encoded bytes are appended directly to the existing uncompressed in-memory data.

If this entry is not already a Data Entry, then the entry is first converted into a Data Entry before the new text data is appended.

  • If the entry is a mapped entry (EntryType = 0), the compressed ZIP entry data is first inflated into memory. The new text data is then appended, and the entry becomes a Data Entry containing the combined uncompressed data.
  • If the entry is a file entry (EntryType = 1), the referenced filesystem file is first loaded into memory. The new text data is then appended, and the entry becomes a Data Entry containing the combined data.

After this method is called, the entry contents exist entirely as uncompressed in-memory data associated with the ZipEntry object.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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CopyToBase64
String copyToBase64()

Returns the compressed data for this ZIP entry as a Base64-encoded string.

This method can only be used when the entry already contains compressed data, meaning the entry is a mapped entry.

This is possible for entries from a ZIP archive that has already been opened, or after writing a ZIP archive while it remains open.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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CopyToHex
String copyToHex()

Returns the compressed data for this ZIP entry as a hexadecimal encoded string.

This method can only be used when the entry already contains compressed data, meaning the entry is a mapped entry.

This is possible for entries from a ZIP archive that has already been opened, or after writing a ZIP archive while it remains open.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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Extract
void extract(String dirPath)

Extracts this ZIP entry beneath the specified base directory.

The entry is extracted according to the relative path stored in the ZIP archive.

For example, if the entry filename is docs/readme.txt and dirPath is c:/temp/output, the file is extracted to c:/temp/output/docs/readme.txt.

Use ExtractInto instead if the file should be extracted directly into a specific directory regardless of the path stored in the ZIP archive.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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ExtractInto
void extractInto(String dirPath)

Extracts this entry directly into the specified directory, ignoring any path information stored in the ZIP entry.

For example, if the entry filename is docs/readme.txt and dirPath is c:/temp/output, the file is extracted to c:/temp/output/readme.txt.

If this entry is a directory entry, nothing is extracted. To create the directory represented by a directory entry, use Extract instead.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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GetNext
boolean getNext()
Introduced in version 11.0.0

Updates this ZipEntry object so that it represents the next entry in the same ZIP archive.

The next entry may be either a file entry or a directory entry.

Returns true if the object was advanced to the next entry. Returns false if there are no more entries.

Never throws: false is an answer, not a failure.

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GetNextMatch
boolean getNextMatch(String pattern)
Introduced in version 11.0.0

Updates this ZipEntry object so that it represents the next entry in the ZIP archive matching the specified wildcard pattern.

The wildcard character * matches zero or more characters. Matching is performed against the full stored filename, including any relative path.

The matching entry may be either a file entry or a directory entry.

Returns true if a matching entry is found. Returns false if no further matching entry exists.

Never throws: false is an answer, not a failure.

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ReplaceString
void replaceString(String strContent, String charset)

Replaces this ZIP entry's existing contents with new text data.

The text is converted to bytes using the character encoding specified by charset, such as utf-8 or ansi.

The resulting bytes become the complete contents of the entry.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

More Information and Examples
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SetDt
void setDt(DateTime dt)

Sets the last-modified date/time for this ZIP entry.

The dt argument is a CkDateTime object containing the date/time to store for the entry.

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UnzipToBd
void unzipToBd(BinData binData)
Introduced in version 9.5.0.67

Unzips this entry directly into a BinData object.

The uncompressed bytes are written to binData.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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UnzipToSb
void unzipToSb(int lineEndingBehavior, String srcCharset, StringBuilder sb)
Introduced in version 9.5.0.67

Unzips this entry as text and appends the result to a StringBuilder.

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as utf-8, utf-16, or windows-1252.

The lineEndingBehavior argument controls line-ending conversion:

  • 0 — leave line endings unchanged.
  • 1 — convert all line endings to bare LF.
  • 2 — convert all line endings to CRLF.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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UnzipToStream
void unzipToStream(Stream toStream)
Introduced in version 9.5.0.67

Unzips this entry to a stream.

If called synchronously, the toStream must have a sink, such as a file or another stream object.

If called asynchronously, the foreground thread can read from the stream while the unzip operation writes to it.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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UnzipToString
String unzipToString(int lineEndingBehavior, String srcCharset)

Inflates this entry and returns the uncompressed data as a string.

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as utf-8, utf-16, or windows-1252.

The lineEndingBehavior argument controls line-ending conversion:

  • 0 — leave line endings unchanged.
  • 1 — convert all line endings to bare LF.
  • 2 — convert all line endings to CRLF.

Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.

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Events

All Chilkat methods are synchronous: the call returns when the work is done. During a long-running call, ZipEntry reports progress through a ProgressListener, an interface with three methods, each with a default, so you override only what you need:

import com.chilkatsoft.chilkat2.ProgressListener;

zipEntry.setProgressListener(new ProgressListener() {
    @Override public boolean percentDone(int pctDone) {
        System.out.println(pctDone + "%");
        return false;           // return true to abort the method in progress
    }
    @Override public void progressInfo(String name, String value) {
        System.out.println(name + ": " + value);
    }
});
zipEntry.setHeartbeatMs(250);   // abortCheck 4 times per second

For a single callback, a lambda is shorter:

zipEntry.onPercentDone(pct -> { System.out.println(pct + "%"); return false; });
public void setProgressListener(ProgressListener listener)

Installs listener as the receiver of this object's events, replacing any listener or lambda installed before; null removes it.

public ProgressListener getProgressListener()

Returns the installed listener, or null.

public void onAbortCheck(BooleanSupplier callback)
public void onPercentDone(IntPredicate callback)
public void onProgressInfo(BiConsumer<String, String> callback)

Each installs a listener whose only callback is the given lambda (from java.util.function). Like setProgressListener, each replaces the listener installed before, so to handle more than one event, implement ProgressListener. null removes the listener.

abortCheck is called at the interval set by the HeartbeatMs property (0, the default, disables it); percentDone is called when an operation's completion percentage is known; progressInfo delivers named progress values. Returning true from abortCheck or percentDone aborts the running method, which then throws ChilkatException.

Callbacks run on the thread that called the method, before it returns. Inside a callback, property accessors of the object (such as setAbortCurrent(true)) and other objects may be used, but calling a method of the same object throws IllegalStateException. An exception thrown by a callback aborts the running method and is rethrown from it; the object remains usable.

AbortCheck
// ProgressListener method (default returns false), or onAbortCheck(BooleanSupplier)
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.

More Information and Examples

Example

import java.util.concurrent.atomic.AtomicBoolean;

final AtomicBoolean stop = new AtomicBoolean(false);   // another thread may call stop.set(true)
zipEntry.setHeartbeatMs(250);                     // call abortCheck 4 times per second
zipEntry.onAbortCheck(() -> stop.get());
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PercentDone
// ProgressListener method (default returns false), or onPercentDone(IntPredicate)
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.

To abort the operation, set the abort output argument to true. This will cause the method to terminate and return a failure status or corresponding failure value.

More Information and Examples

Example

zipEntry.onPercentDone(pct -> {
    // pct ranges from 0 to 100.
    System.out.println("Percent done: " + pct);
    return false;   // return true to abort the method in progress
});
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ProgressInfo
// ProgressListener method (default does nothing), or onProgressInfo(BiConsumer<String, String>)
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

Example

zipEntry.onProgressInfo((name, value) -> System.out.println(name + ": " + value));
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