Completion.java

/*
 * 12/21/2008
 *
 * Completion.java - Represents a single completion choice.
 * 
 * This library is distributed under a modified BSD license.  See the included
 * RSyntaxTextArea.License.txt file for details.
 */
package org.fife.ui.autocomplete;

import javax.swing.Icon;
import javax.swing.text.JTextComponent;


/**
 * Represents a completion choice.  A {@link CompletionProvider} returns lists
 * of objects implementing this interface.  A <tt>Completion</tt> contains the
 * following information:
 * 
 * <ul>
 *   <li>The text the user must (begin to) input for this to be a completion
 *       choice.
 *   <li>The text that will be filled in if the user chooses this completion.
 *       Note that often, this is the same as the text the user must (begin to)
 *       enter, but this doesn't have to be the case.
 *   <li>Summary HTML that describes this completion.  This is information that
 *       can be displayed in a helper "tooltip"-style window beside the
 *       completion list.  This may be <code>null</code>.  It may also be
 *       lazily generated to cut down on memory usage.
 *   <li>The <tt>CompletionProvider</tt> that returned this completion.
 *   <li>Tool tip text that can be displayed when a mouse hovers over this
 *       completion in a text component.
 * </ul>
 *
 * @author Robert Futrell
 * @version 1.0
 * @see AbstractCompletion
 */
public interface Completion extends Comparable<Completion> {


	/**
	 * Compares this completion to another one lexicographically, ignoring
	 * case.
	 *
	 * @param other Another completion instance.
	 * @return How this completion compares to the other one.
	 */
	public int compareTo(Completion other);


	/**
	 * Returns the portion of this completion that has already been entered
	 * into the text component.  The match is case-insensitive.<p>
	 *
	 * This is a convenience method for:
	 * <code>getProvider().getAlreadyEnteredText(comp)</code>.
	 *
	 * @param comp The text component.
	 * @return The already-entered portion of this completion.
	 */
	public String getAlreadyEntered(JTextComponent comp);


	/**
	 * Returns the icon to use for this completion.
	 *
	 * @return The icon, or <code>null</code> for none.
	 */
	public Icon getIcon();


	/**
	 * Returns the text that the user has to (start) typing for this completion
	 * to be offered.  Note that this will usually be the same value as
	 * {@link #getReplacementText()}, but not always (a completion could be
	 * a way to implement shorthand, for example, "<code>sysout</code>" mapping
	 * to "<code>System.out.println(</code>").
	 *
	 * @return The text the user has to (start) typing for this completion to
	 *         be offered.
	 * @see #getReplacementText()
	 */
	public String getInputText();


	/**
	 * Returns the provider that returned this completion.
	 *
	 * @return The provider.
	 */
	public CompletionProvider getProvider();


	/**
	 * Returns the "relevance" of this completion.  This is used when sorting
	 * completions by their relevance.  It is an abstract concept that may
	 * mean different things to different languages, and may depend on the
	 * context of the completion.<p>
	 *
	 * By default, all completions have a relevance of <code>0</code>.  The
	 * higher the value returned by this method, the higher up in the list
	 * this completion will be; the lower the value returned, the lower it will
	 * be.  <code>Completion</code>s with equal relevance values will be
	 * sorted alphabetically.
	 *
	 * @return The relevance of this completion.
	 */
	public int getRelevance();


	/**
	 * Returns the text to insert as the result of this auto-completion.  This
	 * is the "complete" text, including any text that replaces what the user
	 * has already typed.
	 *
	 * @return The replacement text.
	 * @see #getInputText()
	 */
	public String getReplacementText();


	/**
	 * Returns the description of this auto-complete choice.  This can be
	 * used in a popup "description window."
	 *
	 * @return This item's description.  This should be HTML.  It may be
	 *         <code>null</code> if there is no description for this
	 *         completion.
	 */
	public String getSummary();


	/**
	 * Returns the tool tip text to display for mouse hovers over this
	 * completion.<p>
	 *
	 * Note that for this functionality to be enabled, a
	 * <tt>JTextComponent</tt> must be registered with the
	 * <tt>ToolTipManager</tt>, and the text component must know to search
	 * for this value.  In the case of an
	 * <a href="http://fifesoft.com/rsyntaxtextarea">RSyntaxTextArea</a>, this
	 * can be done with a <tt>org.fife.ui.rtextarea.ToolTipSupplier</tt> that
	 * calls into
	 * {@link CompletionProvider#getCompletionsAt(JTextComponent, java.awt.Point)}.
	 *
	 * @return The tool tip text for this completion, or <code>null</code> if
	 *         none.
	 */
	public String getToolTipText();


}