public final Class MappedMemorySegmentImpl

Overrides jdk.internal.foreign.AbstractMemorySegmentImpl.asSlice.

Implements java.lang.foreign.MemorySegment.asSlice.

Doc from java.lang.foreign.MemorySegment.asSlice.

Returns a slice of this memory segment, at the given offset. The returned segment's address is the address of this segment plus the given offset; its size is specified by the given argument.

Equivalent to the following code:

asSlice(offset, newSize, 1);

If this segment is read-only, the returned segment is also read-only.

The returned memory segment shares a region of backing memory with this segment. Hence, no memory will be allocated or freed by this method.

Annotations

@Override

Overrides jdk.internal.foreign.AbstractMemorySegmentImpl.force.

Implements java.lang.foreign.MemorySegment.force.

Doc from java.lang.foreign.MemorySegment.force.

Forces any changes made to the contents of this mapped segment to be written to the storage device described by the mapped segment's file descriptor.

If the file descriptor associated with this mapped segment resides on a local storage device then when this method returns it is guaranteed that all changes made to this segment since it was created, or since this method was last invoked, will have been written to that device.

If the file descriptor associated with this mapped segment does not reside on a local device then no such guarantee is made.

If this segment was not mapped in read/write mode (java.nio.channels.FileChannel.MapMode#READ_WRITE) then invoking this method may have no effect. In particular, the method has no effect for segments mapped in read-only or private mapping modes. This method may or may not have an effect for implementation-specific mapping modes.

Overrides jdk.internal.foreign.AbstractMemorySegmentImpl.isLoaded.

Implements java.lang.foreign.MemorySegment.isLoaded.

Doc from java.lang.foreign.MemorySegment.isLoaded.

Determines whether all the contents of this mapped segment are resident in physical memory.

A return value of true implies that it is highly likely that all the data in this segment is resident in physical memory and may therefore be accessed without incurring any virtual-memory page faults or I/O operations. A return value of false does not necessarily imply that this segment's contents are not resident in physical memory.

The returned value is a hint, rather than a guarantee, because the underlying operating system may have paged out some of this segment's data by the time that an invocation of this method returns.

Overrides jdk.internal.foreign.AbstractMemorySegmentImpl.isMapped.

Implements java.lang.foreign.MemorySegment.isMapped.

Doc from java.lang.foreign.MemorySegment.isMapped.

Returns true if this segment is a mapped segment. A mapped memory segment is created e.g. using the FileChannel#map(FileChannel.MapMode, long, long, Arena) factory, or by wrapping a mapped byte buffer.

Annotations

@Override

Overrides jdk.internal.foreign.AbstractMemorySegmentImpl.load.

Implements java.lang.foreign.MemorySegment.load.

Doc from java.lang.foreign.MemorySegment.load.

Loads the contents of this mapped segment into physical memory.

This method makes a best effort to ensure that, when it returns, the contents of this segment are resident in physical memory. Invoking this method may cause some number of page faults and I/O operations to occur.

Overrides jdk.internal.foreign.AbstractMemorySegmentImpl.unload.

Implements java.lang.foreign.MemorySegment.unload.

Doc from java.lang.foreign.MemorySegment.unload.

Unloads the contents of this mapped segment from physical memory.

This method makes a best effort to ensure that the contents of this segment are no longer resident in physical memory. Accessing this segment's contents after invoking this method may cause some number of page faults and I/O operations to occur (as this segment's contents might need to be paged back in).