An abstract class implementing the ImageInputStream interface. This class is designed to reduce the number of methods that must be implemented by subclasses.

In particular, this class handles most or all of the details of byte order interpretation, buffering, mark/reset, discarding, closing, and disposing.

Constructs an ImageInputStreamImpl.
Closes the stream. Attempts to access a stream that has been closed may result in IOExceptions or incorrect behavior. Calling this method may allow classes implementing this interface to release resources associated with the stream such as memory, disk space, or file descriptors.
Throws
IOExceptionif an I/O error occurs.
Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
objthe reference object with which to compare.
Return
true if this object is the same as the obj argument; false otherwise.
Discards the initial position of the stream prior to the current stream position. Equivalent to flushBefore(getStreamPosition()).
Throws
IOExceptionif an I/O error occurs.
Discards the initial portion of the stream prior to the indicated postion. Attempting to seek to an offset within the flushed portion of the stream will result in an IndexOutOfBoundsException.

Calling flushBefore may allow classes implementing this interface to free up resources such as memory or disk space that are being used to store data from the stream.

Parameters
posa long containing the length of the file prefix that may be flushed.
Throws
IndexOutOfBoundsExceptionif pos lies in the flushed portion of the stream or past the current stream position.
IOExceptionif an I/O error occurs.
Returns the current bit offset, as an integer between 0 and 7, inclusive. The bit offset is updated implicitly by calls to the readBits method. A value of 0 indicates the most-significant bit, and a value of 7 indicates the least significant bit, of the byte being read.

The bit offset is set to 0 when a stream is first opened, and is reset to 0 by calls to seek, skipBytes, or any read or readFully method.

Return
an int containing the bit offset between 0 and 7, inclusive.
Throws
IOExceptionif an I/O error occurs.
See Also
Returns the byte order with which data values will be read from this stream as an instance of the java.nio.ByteOrder enumeration.
Return
one of ByteOrder.BIG_ENDIAN or ByteOrder.LITTLE_ENDIAN, indicating which byte order is being used.
Returns the runtime class of an object. That Class object is the object that is locked by static synchronized methods of the represented class.
Return
The java.lang.Class object that represents the runtime class of the object. The result is of type {@code Class} where X is the erasure of the static type of the expression on which getClass is called.
Returns the earliest position in the stream to which seeking may be performed. The returned value will be the maximum of all values passed into previous calls to flushBefore.
Return
the earliest legal position for seeking, as a long.
Returns the current byte position of the stream. The next read will take place starting at this offset.
Return
a long containing the position of the stream.
Throws
IOExceptionif an I/O error occurs.
Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)

Return
a hash code value for this object.
Returns true if this ImageInputStream caches data itself in order to allow seeking backwards. Applications may consult this in order to decide how frequently, or whether, to flush in order to conserve cache resources.
Return
true if this ImageInputStream caches data.
Returns true if this ImageInputStream caches data itself in order to allow seeking backwards, and the cache is kept in a temporary file. Applications may consult this in order to decide how frequently, or whether, to flush in order to conserve cache resources.
Return
true if this ImageInputStream caches data in a temporary file.
Returns true if this ImageInputStream caches data itself in order to allow seeking backwards, and the cache is kept in main memory. Applications may consult this in order to decide how frequently, or whether, to flush in order to conserve cache resources.
Return
true if this ImageInputStream caches data in main memory.
Returns the total length of the stream, if known. Otherwise, -1 is returned.
Return
a long containing the length of the stream, if known, or else -1.
Throws
IOExceptionif an I/O error occurs.
Marks a position in the stream to be returned to by a subsequent call to reset. Unlike a standard InputStream, all ImageInputStreams support marking. Additionally, calls to mark and reset may be nested arbitrarily.

Unlike the mark methods declared by the Reader InputStream interfaces, no readLimit parameter is used. An arbitrary amount of data may be read following the call to mark.

The bit position used by the readBits method is saved and restored by each pair of calls to mark and reset.

Wakes up a single thread that is waiting on this object's monitor. If any threads are waiting on this object, one of them is chosen to be awakened. The choice is arbitrary and occurs at the discretion of the implementation. A thread waits on an object's monitor by calling one of the wait methods.

The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:

  • By executing a synchronized instance method of that object.
  • By executing the body of a synchronized statement that synchronizes on the object.
  • For objects of type Class, by executing a synchronized static method of that class.

Only one thread at a time can own an object's monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Wakes up all threads that are waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods.

The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Reads a single byte from the stream and returns it as an integer between 0 and 255. If the end of the stream is reached, -1 is returned.

The bit offset within the stream is reset to zero before the read occurs.

Return
a byte value from the stream, as an int, or -1 to indicate EOF.
Throws
IOExceptionif an I/O error occurs.
Reads up to b.length bytes from the stream, and stores them into b starting at index 0. The number of bytes read is returned. If no bytes can be read because the end of the stream has been reached, -1 is returned.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
ban array of bytes to be written to.
Return
the number of bytes actually read, or -1 to indicate EOF.
Throws
NullPointerExceptionif b is null.
IOExceptionif an I/O error occurs.
Reads up to len bytes from the stream, and stores them into b starting at index off. The number of bytes read is returned. If no bytes can be read because the end of the stream has been reached, -1 is returned.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
ban array of bytes to be written to.
offthe starting position within b to write to.
lenthe maximum number of bytes to read.
Return
the number of bytes actually read, or -1 to indicate EOF.
Throws
NullPointerExceptionif b is null.
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than b.length.
IOExceptionif an I/O error occurs.
Reads a single bit from the stream and returns it as an int with the value 0 or 1. The bit offset is advanced by one and reduced modulo 8.
Return
an int containing the value 0 or 1.
Throws
EOFExceptionif the stream reaches the end before reading all the bits.
IOExceptionif an I/O error occurs.
Reads a bitstring from the stream and returns it as a long, with the first bit read becoming the most significant bit of the output. The read starts within the byte indicated by getStreamPosition, at the bit given by getBitOffset. The bit offset is advanced by numBits and reduced modulo 8.

The byte order of the stream has no effect on this method. The return value of this method is constructed as though the bits were read one at a time, and shifted into the right side of the return value, as shown by the following pseudo-code:

 long accum = 0L;
 for (int i = 0; i < numBits; i++) {
   accum <<= 1; // Shift left one bit to make room
   accum |= readBit();
 }
 
Note that the result of readBits(32) may thus not be equal to that of readInt() if a reverse network byte order is being used (i.e., getByteOrder() == false).

If the end of the stream is encountered before all the bits have been read, an EOFException is thrown.

Parameters
numBitsthe number of bits to read, as an int between 0 and 64, inclusive.
Return
the bitstring, as a long with the last bit read stored in the least significant bit.
Throws
IllegalArgumentExceptionif numBits is not between 0 and 64, inclusive.
EOFExceptionif the stream reaches the end before reading all the bits.
IOExceptionif an I/O error occurs.
Reads a byte from the stream and returns a boolean value of true if it is nonzero, false if it is zero.

The bit offset within the stream is reset to zero before the read occurs.

Return
a boolean value from the stream.
Throws
EOFExceptionif the end of the stream is reached.
IOExceptionif an I/O error occurs.
Reads a byte from the stream and returns it as a byte value. Byte values between 0x00 and 0x7f represent integer values between 0 and 127. Values between 0x80 and 0xff represent negative values from -128 to /1.

The bit offset within the stream is reset to zero before the read occurs.

Return
a signed byte value from the stream.
Throws
EOFExceptionif the end of the stream is reached.
IOExceptionif an I/O error occurs.
Reads up to len bytes from the stream, and modifies the supplied IIOByteBuffer to indicate the byte array, offset, and length where the data may be found. The caller should not attempt to modify the data found in the IIOByteBuffer.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
bufan IIOByteBuffer object to be modified.
lenthe maximum number of bytes to read.
Throws
IndexOutOfBoundsExceptionif len is negative.
NullPointerExceptionif buf is null.
IOExceptionif an I/O error occurs.
Equivalent to readUnsignedShort, except that the result is returned using the char datatype.

The bit offset within the stream is reset to zero before the read occurs.

Return
an unsigned char value from the stream.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads 8 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a double.

The bit offset within the stream is reset to zero before the read occurs.

Return
a double value from the stream.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a float.

The bit offset within the stream is reset to zero before the read occurs.

Return
a float value from the stream.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads b.length bytes from the stream, and stores them into b starting at index 0. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
ban array of bytes.
Throws
NullPointerExceptionif b is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len bytes from the stream, and stores them into b starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
ban array of bytes to be written to.
offthe starting position within b to write to.
lenthe maximum number of bytes to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than b.length.
NullPointerExceptionif b is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len chars (unsigned 16-bit integers) from the stream according to the current byte order, and stores them into c starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
can array of chars to be written to.
offthe starting position withinb to write to.
lenthe maximum number of chars to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than c.length.
NullPointerExceptionif c is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len doubles (64-bit IEEE double-precision floats) from the stream according to the current byte order, and stores them into d starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
dan array of doubles to be written to.
offthe starting position withinb to write to.
lenthe maximum number of doubles to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than d.length.
NullPointerExceptionif d is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len floats (32-bit IEEE single-precision floats) from the stream according to the current byte order, and stores them into f starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
fan array of floats to be written to.
offthe starting position withinb to write to.
lenthe maximum number of floats to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than f.length.
NullPointerExceptionif f is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len ints (signed 32-bit integers) from the stream according to the current byte order, and stores them into i starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
ian array of ints to be written to.
offthe starting position withinb to write to.
lenthe maximum number of ints to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than i.length.
NullPointerExceptionif i is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len longs (signed 64-bit integers) from the stream according to the current byte order, and stores them into l starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
lan array of longs to be written to.
offthe starting position withinb to write to.
lenthe maximum number of longs to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than l.length.
NullPointerExceptionif l is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads len shorts (signed 16-bit integers) from the stream according to the current byte order, and stores them into s starting at index off. If the end of the stream is reached, an EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Parameters
san array of shorts to be written to.
offthe starting position withinb to write to.
lenthe maximum number of shorts to read.
Throws
IndexOutOfBoundsExceptionif off is negative, len is negative, or off + len is greater than s.length.
NullPointerExceptionif s is null.
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as an int.

The bit offset within the stream is ignored and treated as though it were zero.

Return
a signed int value from the stream.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads the next line of text from the input stream. It reads successive bytes, converting each byte separately into a character, until it encounters a line terminator or end of file; the characters read are then returned as a String. Note that because this method processes bytes, it does not support input of the full Unicode character set.

If end of file is encountered before even one byte can be read, then null is returned. Otherwise, each byte that is read is converted to type char by zero-extension. If the character '\n' is encountered, it is discarded and reading ceases. If the character '\r' is encountered, it is discarded and, if the following byte converts to the character '\n', then that is discarded also; reading then ceases. If end of file is encountered before either of the characters '\n' and '\r' is encountered, reading ceases. Once reading has ceased, a String is returned that contains all the characters read and not discarded, taken in order. Note that every character in this string will have a value less than \u0100, that is, (char)256.

The bit offset within the stream is reset to zero before the read occurs.

Return
a String containing a line of text from the stream.
Throws
IOExceptionif an I/O error occurs.
Reads 8 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a long.

The bit offset within the stream is reset to zero before the read occurs.

Return
a signed long value from the stream.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads two bytes from the stream, and (conceptually) concatenates them according to the current byte order, and returns the result as a short value.

The bit offset within the stream is reset to zero before the read occurs.

Return
a signed short value from the stream.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads a byte from the stream, and (conceptually) converts it to an int, masks it with 0xff in order to strip off any sign-extension bits, and returns it as a byte value.

Thus, byte values between 0x00 and 0x7f are simply returned as integer values between 0 and 127. Values between 0x80 and 0xff, which normally represent negative bytevalues, will be mapped into positive integers between 128 and 255.

The bit offset within the stream is reset to zero before the read occurs.

Return
an unsigned byte value from the stream.
Throws
EOFExceptionif the end of the stream is reached.
IOExceptionif an I/O error occurs.
Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the result to a long, masks it with 0xffffffffL in order to strip off any sign-extension bits, and returns the result as an unsigned long value.

The bit offset within the stream is reset to zero before the read occurs.

Return
an unsigned int value from the stream, as a long.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads two bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the resulting value to an int, masks it with 0xffff in order to strip off any sign-extension buts, and returns the result as an unsigned int value.

The bit offset within the stream is reset to zero before the read occurs.

Return
an unsigned short value from the stream, as an int.
Throws
EOFExceptionif the stream reaches the end before reading all the bytes.
IOExceptionif an I/O error occurs.
See Also
Reads in a string that has been encoded using a modified UTF-8 format. The general contract of readUTF is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.

First, two bytes are read and used to construct an unsigned 16-bit integer in the manner of the readUnsignedShort method, using network byte order (regardless of the current byte order setting). This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.

If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.

If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:


 (char)(((a& 0x1F) << 6) | (b & 0x3F))
 
If the first byte of a group matches the bit pattern 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:


 (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
 
If the first byte of a group matches the pattern 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown.

If end of file is encountered at any time during this entire process, then an EOFException is thrown.

After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.

The current byte order setting is ignored.

The bit offset within the stream is reset to zero before the read occurs.

Note: This method should not be used in the implementation of image formats that use standard UTF-8, because the modified UTF-8 used here is incompatible with standard UTF-8.

Return
a String read from the stream.
Throws
EOFExceptionif this stream reaches the end before reading all the bytes.
UTFDataFormatExceptionif the bytes do not represent a valid modified UTF-8 encoding of a string.
IOExceptionif an I/O error occurs.
Returns the file pointer to its previous position, including the bit offset, at the time of the most recent unmatched call to mark.

Calls to reset without a corresponding call to mark have no effect.

An IOException will be thrown if the previous marked position lies in the discarded portion of the stream.

Throws
IOExceptionif an I/O error occurs.
Sets the current stream position to the desired location. The next read will occur at this location. The bit offset is set to 0.

An IndexOutOfBoundsException will be thrown if pos is smaller than the flushed position (as returned by getflushedPosition).

It is legal to seek past the end of the file; an EOFException will be thrown only if a read is performed.

Parameters
posa long containing the desired file pointer position.
Throws
IndexOutOfBoundsExceptionif pos is smaller than the flushed position.
IOExceptionif any other I/O error occurs.
Sets the bit offset to an integer between 0 and 7, inclusive. The byte offset within the stream, as returned by getStreamPosition, is left unchanged. A value of 0 indicates the most-significant bit, and a value of 7 indicates the least significant bit, of the byte being read.
Parameters
bitOffsetthe desired offset, as an int between 0 and 7, inclusive.
Throws
IllegalArgumentExceptionif bitOffset is not between 0 and 7, inclusive.
IOExceptionif an I/O error occurs.
See Also
Sets the desired byte order for future reads of data values from this stream. For example, the sequence of bytes '0x01 0x02 0x03 0x04' if read as a 4-byte integer would have the value '0x01020304' using network byte order and the value '0x04030201' under the reverse byte order.

The enumeration class java.nio.ByteOrder is used to specify the byte order. A value of ByteOrder.BIG_ENDIAN specifies so-called big-endian or network byte order, in which the high-order byte comes first. Motorola and Sparc processors store data in this format, while Intel processors store data in the reverse ByteOrder.LITTLE_ENDIAN order.

The byte order has no effect on the results returned from the readBits method (or the value written by ImageOutputStream.writeBits).

Parameters
byteOrderone of ByteOrder.BIG_ENDIAN or java.nio.ByteOrder.LITTLE_ENDIAN, indicating whether network byte order or its reverse will be used for future reads.
Moves the stream position forward by a given number of bytes. It is possible that this method will only be able to skip forward by a smaller number of bytes than requested, for example if the end of the stream is reached. In all cases, the actual number of bytes skipped is returned. The bit offset is set to zero prior to advancing the position.
Parameters
nan int containing the number of bytes to be skipped.
Return
an int representing the number of bytes skipped.
Throws
IOExceptionif an I/O error occurs.
Moves the stream position forward by a given number of bytes. This method is identical to skipBytes(int) except that it allows for a larger skip distance.
Parameters
na long containing the number of bytes to be skipped.
Return
a long representing the number of bytes skipped.
Throws
IOExceptionif an I/O error occurs.
Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 
Return
a string representation of the object.
Causes current thread to wait until another thread invokes the method or the method for this object. In other words, this method behaves exactly as if it simply performs the call wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method. The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait();
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Throws
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.

The current thread must own this object's monitor.

This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:

  • Some other thread invokes the notify method for this object and thread T happens to be arbitrarily chosen as the thread to be awakened.
  • Some other thread invokes the notifyAll method for this object.
  • Some other thread interrupts thread T.
  • The specified amount of real time has elapsed, more or less. If timeout is zero, however, then real time is not taken into consideration and the thread simply waits until notified.
The thread T is then removed from the wait set for this object and re-enabled for thread scheduling. It then competes in the usual manner with other threads for the right to synchronize on the object; once it has gained control of the object, all its synchronization claims on the object are restored to the status quo ante - that is, to the situation as of the time that the wait method was invoked. Thread T then returns from the invocation of the wait method. Thus, on return from the wait method, the synchronization state of the object and of thread T is exactly as it was when the wait method was invoked.

A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout);
         ... // Perform action appropriate to condition
     }
 
(For more information on this topic, see Section 3.2.3 in Doug Lea's "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, 2000), or Item 50 in Joshua Bloch's "Effective Java Programming Language Guide" (Addison-Wesley, 2001).

If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.

Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Parameters
timeoutthe maximum time to wait in milliseconds.
Throws
IllegalArgumentExceptionif the value of timeout is negative.
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

This method is similar to the wait method of one argument, but it allows finer control over the amount of time to wait for a notification before giving up. The amount of real time, measured in nanoseconds, is given by:

 1000000*timeout+nanos

In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:

  • Another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method.
  • The timeout period, specified by timeout milliseconds plus nanos nanoseconds arguments, has elapsed.

The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout, nanos);
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Parameters
timeoutthe maximum time to wait in milliseconds.
nanosadditional time, in nanoseconds range 0-999999.
Throws
IllegalArgumentExceptionif the value of timeout is negative or the value of nanos is not in the range 0-999999.
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.