Stream Chilkat2 Java Reference Documentation
Stream
Current Version: 11.7.0
Markdown version of this page for AI tools (v 11.7.0) · all AI docs
Chilkat.Stream
Stream from a source file, byte array, string, or selected file part
without manually loading or copying all data first.
Write streamed data to a sink file, append to an existing file, or output
to
Read or write raw bytes, fixed byte counts, encoded byte strings,
individual bytes, or
Read and write strings using
Control read and write wait behavior, poll for immediately available
data, and inspect read or write failure reasons.
Track bytes sent and received, detect end-of-stream or write-closed
state, reset streams, close writing, and abort long-running operations.
Read, write, pipe, monitor, and control byte or text streams.
Chilkat.Stream is a general-purpose streaming object for moving
data between sources and sinks without requiring the entire payload to be
handled at once. A stream can read from files, byte arrays, strings, or other
sources; write to files, memory, BinData,
StringBuilder, or other sinks; handle binary and text data;
apply character-set rules for strings; process file parts; track bytes sent
and received; and support timeouts, polling, aborts, async task integration,
and end-of-stream handling.
File and memory sources
File and object sinks
BinData, StringBuilder, bytes, or strings.
Binary reads and writes
BinData content.
Text streaming
StringCharset, optionally use a
BOM, and read text until CRLF or a matching delimiter.
Timeouts and polling
Progress and lifecycle
BinData, or
StringBuilder. Check EndOfStream,
ReadFailReason, WriteFailReason,
NumReceived, NumSent, and
LastErrorText to understand stream progress and failures.
ReadTimeoutMs, a value of 0 means a polling
read, not an infinite timeout. For WriteTimeoutMs,
0 means return immediately if the stream cannot be written to
right away.
Object Creation
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Stream;
try (Stream stream = new Stream()) {
// ... use stream ...
} catch (ChilkatException e) {
System.out.println(e.getMessage()); // "Stream.someMethod failed: <reason>"
System.out.println(e.getLastErrorText()); // the full log of the failed call
}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).
Releases the native object (Stream 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.
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
AbortCurrent
boolean getAbortCurrent()
void setAbortCurrent(boolean value)
When set to true, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to false when the next method is called. When the abort occurs, this property is reset to false. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)
CanRead
boolean getCanRead()
true if the stream supports reading. Otherwise false.
Note: A stream that supports reading, which has already reached the end-of-stream, will still have a CanRead value of true. This property indicates the stream's inherent ability, and not whether or not the stream can be read at a particular moment in time.
CanWrite
boolean getCanWrite()
true if the stream supports writing. Otherwise false.
Note: A stream that supports writing, which has already been closed for write, will still have a CanWrite value of true. This property indicates the stream's inherent ability, and not whether or not the stream can be written at a particular moment in time.
DataAvailable
boolean getDataAvailable()
true if it is known for sure that data is ready and waiting to be read. false if it is not known for sure (it may be that data is immediately available, but reading the stream with a ReadTimeoutMs of 0, which is to poll the stream, is the way to find out).
DebugLogFilePath
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.
DefaultChunkSize
int getDefaultChunkSize()
void setDefaultChunkSize(int value)
The default internal chunk size for reading or writing. The default value is 65536. If this property is set to 0, it will cause the default chunk size (65536) to be used. Note: The chunk size can have significant performance impact. If performance is an issue, be sure to experiment with different chunk sizes.
topEndOfStream
boolean getEndOfStream()
true if the end-of-stream has already been reached. When the stream has already ended, all calls to Read* methods will return false with the ReadFailReason set to 3 (already at end-of-stream).
HeartbeatMs
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.
IsWriteClosed
boolean getIsWriteClosed()
true if the stream is closed for writing. Once closed, no more data may be written to the stream.
LastErrorHtml
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.
topLastErrorText
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.
LastErrorXml
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.
topLastMethodSuccess
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.
Length
long getLength()
void setLength(long value)
The length (in bytes) of the stream's source. If unknown, then this property will have a value of -1. This property may be set by the application if it knows in advance the length of the stream.
topLength32
int getLength32()
void setLength32(int value)
The length (in bytes) of the stream's source. If unknown, then this property will have a value of -1. This property may be set by the application if it knows in advance the length of the stream.
Setting this property also sets the Length property (which is a 64-bit integer).
topNumReceived
long getNumReceived()
The number of bytes received by the stream.
topNumSent
long getNumSent()
The number of bytes sent by the stream.
topReadFailReason
int getReadFailReason()
This property is automatically set when a Read* method is called. It indicates the reason for failure. Possible values are:
- 0>
- No failure (success)
- Timeout, or no data is immediately available for a polling read.
- Aborted by an application callback.
- Already at end-of-stream.
- Fatal stream error.
- Out-of-memory error (this is very unlikely).
ReadTimeoutMs
int getReadTimeoutMs()
void setReadTimeoutMs(int value)
The maximum number of seconds to wait while reading. The default value is 30 seconds (i.e. 30000ms). A value of 0 indicates a poll. (A polling read is to return with a timeout if no data is immediately available.)
Important: For most Chilkat timeout related properties, a value of 0 indicates an infinite timeout. For this property, a value of 0 indicates a poll. If setting a timeout related property (or method argument) to zero, be sure to understand if 0 means wait forever or poll.
The timeout value is not a total timeout. It is the maximum time to wait while no additional data is forthcoming.
topSinkFile
String getSinkFile()
void setSinkFile(String value)
Sets the sink to the path of a file. The file does not need to exist at the time of setting this property. The sink file will be automatically opened on demand, when the stream is first written.
Note: This property takes priority over other potential sinks. Make sure this property is set to an empty string if the stream's sink is to be something else.
topSinkFileAppend
boolean getSinkFileAppend()
void setSinkFileAppend(boolean value)
If true, the stream appends to the SinkFile rather than truncating and re-writing the sink file. The default value is false.
SourceFile
String getSourceFile()
void setSourceFile(String value)
Sets the source to the path of a file. The file does not need to exist at the time of setting this property. The source file will be automatically opened on demand, when the stream is first read.
Note: This property takes priority over other potential sources. Make sure this property is set to an empty string if the stream's source is to be something else.
topSourceFilePart
int getSourceFilePart()
void setSourceFilePart(int value)
If the source is a file, then this property can be used to stream one part of the file. The SourceFilePartSize property defines the size (in bytes) of each part. The SourceFilePart and SourceFilePartSize have default values of 0, which means the entire SourceFile is streamed.
This property is a 0-based index. For example, if the SourceFilePartSize is 1000, then part 0 is for bytes 0 to 999, part 1 is for bytes 1000 to 1999, etc.
SourceFilePartSize
int getSourceFilePartSize()
void setSourceFilePartSize(int value)
If the source is a file, then this property, in conjunction with the SourceFilePart property, can be used to stream a single part of the file. This property defines the size (in bytes) of each part. The SourceFilePart and SourceFilePartSize have default values of 0, which means that by default, the entire SourceFile is streamed.
StringBom
boolean getStringBom()
void setStringBom(boolean value)
If true, then include the BOM when creating a string source via SetSourceString where the charset is utf-8, utf-16, etc. (The term BOM stands for Byte Order Mark, also known as the preamble.) Also, if true, then include the BOM when writing a string via the WriteString method. The default value of this property is false.
StringCharset
String getStringCharset()
void setStringCharset(String value)
Indicates the expected character encoding, such as utf-8, windows-1256, utf-16, etc. for methods that read text such as: ReadString, ReadToCRLF, ReadUntilMatch. Also controls the character encoding when writing strings with the WriteString method. The supported charsets are indicated at the link below.
The default value is utf-8.
VerboseLogging
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.
Version
String getVersion()
WriteFailReason
int getWriteFailReason()
This property is automatically set when a Write* method is called. It indicates the reason for failure. Possible values are:
- 0>
- No failure (success)
- Timeout, or unable to immediately write when the WriteTimeoutMs is 0.
- Aborted by an application callback.
- The stream has already ended.
- Fatal stream error.
- Out-of-memory error (this is very unlikely).
WriteTimeoutMs
int getWriteTimeoutMs()
void setWriteTimeoutMs(int value)
The maximum number of seconds to wait while writing. The default value is 30 seconds (i.e. 30000ms). A value of 0 indicates to return immediately if it is not possible to write to the sink immediately.
topMethods
ReadBd
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The incoming data is appended to binData.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
ReadBytesENC
The same as ReadBytes, except returns the received bytes in encoded string form. The encoding argument indicates the encoding, which can be base64, hex, or any of the multitude of encodings indicated in the link below.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
ReadNBytesENC
The same as ReadNBytes, except returns the received bytes in encoded string form. The encoding argument indicates the encoding, which can be base64, hex, or any of the multitude of encodings indicated in the link below.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
ReadSb
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is appended to sb. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to utf-8 prior to calling ReadSb.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
ReadString
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is returned as a string. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to utf-8 prior to calling ReadString.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
ReadToCRLF
Reads the stream until a CRLF is received. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is returned as a string. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to utf-8 prior to calling ReadString.
Note: If the end-of-stream is reached prior to receiving the CRLF, then the remaining data is returned, and the ReadFailReason property will be set to 3 (to indicate end-of-file). This is the only case where as string would be returned that does not end with CRLF.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
ReadUntilMatch
Reads the stream until the string indicated by matchStr is received. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is returned as a string. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to utf-8 prior to calling ReadString.
Note: If the end-of-stream is reached prior to receiving the match string, then the remaining data is returned, and the ReadFailReason property will be set to 3 (to indicate end-of-file). This is the only case where as string would be returned that does not end with the desired match string.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
Reset
Resets the stream. If a source or sink is open, then it is closed. Properties such as EndOfStream and IsWriteClose are reset to default values.
topSetSourceString
Sets the stream's source to the contents of srcStr. The charset indicates the character encoding to be used for the byte representation of the srcStr.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
WriteBd
Writes the contents of binData to the stream.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
WriteByte
Writes a single byte to the stream. The byteVal must have a value from 0 to 255.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
WriteBytesENC
Writes binary bytes to a stream. The byte data is passed in encoded string form, where the encoding can be base64, hex, or any of the supported binary encodings listed at the link below.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
WriteClose
Indicates that no more data will be written to the stream.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
WriteSb
Writes the contents of sb to the stream. The actual bytes written are the byte representation of the string as indicated by the StringCharset property. For example, to write utf-8 bytes, first set StringCharset equal to utf-8 and then call WriteSb.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
WriteString
Writes a string to a stream. The actual bytes written are the byte representation of the string as indicated by the StringCharset property. For example, to write utf-8 bytes, first set StringCharset equal to utf-8 and then call WriteString.
Throws ChilkatException on failure; e.getLastErrorText() (or the object's getLastErrorText()) explains why, and the object remains usable.
Events
All Chilkat methods are synchronous: the call returns when the work is done. During a long-running call, Stream 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;
stream.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);
}
});
stream.setHeartbeatMs(250); // abortCheck 4 times per secondFor a single callback, a lambda is shorter:
stream.onPercentDone(pct -> { System.out.println(pct + "%"); return false; });Installs listener as the receiver of this object's events, replacing any listener or lambda installed before; null removes it.
Returns the installed listener, or null.
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
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.
Example
import java.util.concurrent.atomic.AtomicBoolean;
final AtomicBoolean stop = new AtomicBoolean(false); // another thread may call stop.set(true)
stream.setHeartbeatMs(250); // call abortCheck 4 times per second
stream.onAbortCheck(() -> stop.get());PercentDone
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.
Example
stream.onPercentDone(pct -> {
// pct ranges from 0 to 100.
System.out.println("Percent done: " + pct);
return false; // return true to abort the method in progress
});ProgressInfo
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.
Example
stream.onProgressInfo((name, value) -> System.out.println(name + ": " + value));