wordbreaktable.java

来自「《移动Agent技术》一书的所有章节源代码。」· Java 代码 · 共 102 行

/*
 * @(#)WordBreakTable.java	1.2 97/10/28
 *
 * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
 * (C) Copyright IBM Corp. 1996 - All Rights Reserved
 *
 * Portions copyright (c) 1996 Sun Microsystems, Inc. All Rights Reserved.
 *
 *   The original version of this source code and documentation is copyrighted
 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
 * materials are provided under terms of a License Agreement between Taligent
 * and Sun. This technology is protected by multiple US and International
 * patents. This notice and attribution to Taligent may not be removed.
 *   Taligent is a registered trademark of Taligent, Inc.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 */

package java.text;

/**
 * This class implements a state transition table.
 * After each transition, using the get method, the
 * new state is returned along with information about
 * the state change (ex. was it a "marked" transition").
 * This class is internal only.
 */
final class WordBreakTable
{
    /**
     * Construct a table using existing data.  See SentenceBreakBoundary and
     * the other SimpleTextBoundary subclasses for examples.
     * @param cols number of columns in the table
     * @param data an encoded byte array containing state and transition data
     */
    public WordBreakTable(int cols, byte data[])
    {
        this.data = data;
        this.cols = cols;
    }

    /**
     * Get the resulting state moving from oldState accepting input
     * @param oldState current state
     * @param input input
     * @return int resulting state and transition data
     */
    public int get(int oldState, int input)
    {
        return data[(oldState & INDEX_MASK) * cols + input];
    }

    /**
     * Checks to see if the transition into the specified state was "marked"
     * @param state the state as returned by get, initialState, or endState
     * @return true if transition into state was marked.
     */
    public boolean isMarkState(int state)
    {
        return (state & MARK_MASK) != 0;
    }

    /**
     * Check is a state is the end state
     * @param state the state to check
     * @return true if state is an end state
     */
    public boolean isEndState(int state)
    {
        return (state & INDEX_MASK) == END_STATE;
    }

    /**
     * Get the start state
     * @return the initial state
     */
    public int initialState()
    {
        return INITIAL_STATE;
    }

    static final byte MARK_MASK = (byte)0x80;
    static final byte INDEX_MASK = (byte)0x7F;
    private static final int INITIAL_STATE = 1;
    private static final int END_STATE = 0;
    private byte data[];
    private int cols;
}