Interface IBuffer


  • public interface IBuffer
    A buffer contains the text contents of a resource. It is not language-specific. The contents may be in the process of being edited, differing from the actual contents of the underlying resource. A buffer has an owner, which is an IOpenable. If a buffer does not have an underlying resource, saving the buffer has no effect. Buffers can be read-only.

    Note that java model operations that manipulate an IBuffer (for example, IType.createMethod(...)) ensures that the same line delimiter (either "\n" or "\r" or "\r\n") is used across the whole buffer. Thus these operations may change the line delimiter(s) included in the string to be append, or replaced. However implementers of this interface should be aware that other clients of IBuffer might not do such transformations beforehand.

    This interface may be implemented by clients.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void addBufferChangedListener​(IBufferChangedListener listener)
      Adds the given listener for changes to this buffer.
      void append​(char[] text)
      Appends the given character array to the contents of the buffer.
      void append​(String text)
      Appends the given string to the contents of the buffer.
      void close()
      Closes the buffer.
      char getChar​(int position)
      Returns the character at the given position in this buffer.
      char[] getCharacters()
      Returns the contents of this buffer as a character array, or null if the buffer has not been initialized.
      String getContents()
      Returns the contents of this buffer as a String.
      int getLength()
      Returns number of characters stored in this buffer.
      IOpenable getOwner()
      Returns the Java openable element owning of this buffer.
      String getText​(int offset, int length)
      Returns the given range of text in this buffer.
      IResource getUnderlyingResource()
      Returns the underlying resource for which this buffer was opened, or null if this buffer was not opened on a resource.
      boolean hasUnsavedChanges()
      Returns whether this buffer has been modified since it was opened or since it was last saved.
      boolean isClosed()
      Returns whether this buffer has been closed.
      boolean isReadOnly()
      Returns whether this buffer is read-only.
      void removeBufferChangedListener​(IBufferChangedListener listener)
      Removes the given listener from this buffer.
      void replace​(int position, int length, char[] text)
      Replaces the given range of characters in this buffer with the given text.
      void replace​(int position, int length, String text)
      Replaces the given range of characters in this buffer with the given text.
      void save​(IProgressMonitor progress, boolean force)
      Saves the contents of this buffer to its underlying resource.
      void setContents​(char[] contents)
      Sets the contents of this buffer to the given character array.
      void setContents​(String contents)
      Sets the contents of this buffer to the given String.
    • Method Detail

      • addBufferChangedListener

        void addBufferChangedListener​(IBufferChangedListener listener)
        Adds the given listener for changes to this buffer. Has no effect if an identical listener is already registered or if the buffer is closed.
        Parameters:
        listener - the listener of buffer changes
      • append

        void append​(char[] text)
        Appends the given character array to the contents of the buffer. This buffer will now have unsaved changes. Any client can append to the contents of the buffer, not just the owner of the buffer. Reports a buffer changed event.

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        text - the given character array to append to contents of the buffer
      • append

        void append​(String text)
        Appends the given string to the contents of the buffer. This buffer will now have unsaved changes. Any client can append to the contents of the buffer, not just the owner of the buffer. Reports a buffer changed event.

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        text - the String to append to the contents of the buffer
      • close

        void close()
        Closes the buffer. Any unsaved changes are lost. Reports a buffer changed event with a 0 offset and a 0 length. When this event is fired, the buffer should already be closed.

        Further operations on the buffer are not allowed, except for close. If an attempt is made to close an already closed buffer, the second attempt has no effect.

      • getChar

        char getChar​(int position)
        Returns the character at the given position in this buffer.

        The returned value is undefined if the buffer is closed.

        Parameters:
        position - a zero-based source offset in this buffer
        Returns:
        the character at the given position in this buffer
      • getCharacters

        char[] getCharacters()
        Returns the contents of this buffer as a character array, or null if the buffer has not been initialized.

        Callers should make no assumption about whether the returned character array is or is not the genuine article or a copy. In other words, if the client wishes to change this array, they should make a copy. Likewise, if the client wishes to hang on to the array in its current state, they should make a copy.

        The returned value is undefined if the buffer is closed.

        Returns:
        the characters contained in this buffer
      • getContents

        String getContents()
        Returns the contents of this buffer as a String. Like all strings, the result is an immutable value object., It can also answer null if the buffer has not been initialized.

        The returned value is undefined if the buffer is closed.

        Returns:
        the contents of this buffer as a String
      • getLength

        int getLength()
        Returns number of characters stored in this buffer.

        The returned value is undefined if the buffer is closed.

        Returns:
        the number of characters in this buffer
      • getOwner

        IOpenable getOwner()
        Returns the Java openable element owning of this buffer.
        Returns:
        the openable element owning this buffer
      • getText

        String getText​(int offset,
                       int length)
                throws IndexOutOfBoundsException
        Returns the given range of text in this buffer.

        The returned value is undefined if the buffer is closed.

        Parameters:
        offset - the zero-based starting offset
        length - the number of characters to retrieve
        Returns:
        the given range of text in this buffer
        Throws:
        IndexOutOfBoundsException - when buffer is out of synch
      • getUnderlyingResource

        IResource getUnderlyingResource()
        Returns the underlying resource for which this buffer was opened, or null if this buffer was not opened on a resource.
        Returns:
        the underlying resource for this buffer, or null if none.
      • hasUnsavedChanges

        boolean hasUnsavedChanges()
        Returns whether this buffer has been modified since it was opened or since it was last saved. If a buffer does not have an underlying resource, this method always returns true.

        NOTE: when a buffer does not have unsaved changes, the model may decide to close it to claim some memory back. If the associated element needs to be reopened later on, its buffer factory will be requested to create a new buffer.

        Returns:
        a boolean indicating presence of unsaved changes (in the absence of any underlying resource, it will always return true).
      • isClosed

        boolean isClosed()
        Returns whether this buffer has been closed.
        Returns:
        a boolean indicating whether this buffer is closed.
      • isReadOnly

        boolean isReadOnly()
        Returns whether this buffer is read-only.
        Returns:
        a boolean indicating whether this buffer is read-only
      • removeBufferChangedListener

        void removeBufferChangedListener​(IBufferChangedListener listener)
        Removes the given listener from this buffer. Has no effect if an identical listener is not registered or if the buffer is closed.
        Parameters:
        listener - the listener
      • replace

        void replace​(int position,
                     int length,
                     char[] text)
        Replaces the given range of characters in this buffer with the given text. position and position + length must be in the range [0, getLength()]. length must not be negative.

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        position - the zero-based starting position of the affected text range in this buffer
        length - the length of the affected text range in this buffer
        text - the replacing text as a character array
      • replace

        void replace​(int position,
                     int length,
                     String text)
        Replaces the given range of characters in this buffer with the given text. position and position + length must be in the range [0, getLength()]. length must not be negative.

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        position - the zero-based starting position of the affected text range in this buffer
        length - the length of the affected text range in this buffer
        text - the replacing text as a String
      • save

        void save​(IProgressMonitor progress,
                  boolean force)
           throws JavaModelException
        Saves the contents of this buffer to its underlying resource. If successful, this buffer will have no unsaved changes. The buffer is left open. Saving a buffer with no unsaved changes has no effect - the underlying resource is not changed. If the buffer does not have an underlying resource or is read-only, this has no effect.

        The force parameter controls how this method deals with cases where the workbench is not completely in sync with the local file system. If false is specified, this method will only attempt to overwrite a corresponding file in the local file system provided it is in sync with the workbench. This option ensures there is no unintended data loss; it is the recommended setting. However, if true is specified, an attempt will be made to write a corresponding file in the local file system, overwriting any existing one if need be. In either case, if this method succeeds, the resource will be marked as being local (even if it wasn't before).

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        progress - the progress monitor to notify
        force - a boolean flag indicating how to deal with resource inconsistencies.
        Throws:
        JavaModelException - if an error occurs writing the buffer to the underlying resource
        See Also:
        IFile.setContents(java.io.InputStream, boolean, boolean, org.eclipse.core.runtime.IProgressMonitor)
      • setContents

        void setContents​(char[] contents)
        Sets the contents of this buffer to the given character array. This buffer will now have unsaved changes. Any client can set the contents of the buffer, not just the owner of the buffer. Reports a buffer changed event.

        Equivalent to replace(0,getLength(),contents).

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        contents - the new contents of this buffer as a character array
      • setContents

        void setContents​(String contents)
        Sets the contents of this buffer to the given String. This buffer will now have unsaved changes. Any client can set the contents of the buffer, not just the owner of the buffer. Reports a buffer changed event.

        Equivalent to replace(0,getLength(),contents).

        Has no effect if this buffer is read-only or if the buffer is closed.

        Parameters:
        contents - the new contents of this buffer as a String