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/**
 *  Copyright (c) 1997-2013, www.tinygroup.org ([email protected]).
 *
 *  Licensed under the GPL, Version 3.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.gnu.org/licenses/gpl.html
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.tinygroup.commons.tools;

import java.io.Serializable;

/**
 * 基本常量。
 *
 * @author renhui
 */
public final class BasicConstant {
    // =============================================================
    //  数组常量
    // =============================================================

    // primitive arrays

    /** 空的byte数组。 */
    public static final byte[] EMPTY_BYTE_ARRAY        = new byte[0];
    public static final Byte[] EMPTY_BYTE_OBJECT_ARRAY = new Byte[0];

    /** 空的short数组。 */
    public static final short[] EMPTY_SHORT_ARRAY        = new short[0];
    public static final Short[] EMPTY_SHORT_OBJECT_ARRAY = new Short[0];

    /** 空的int数组。 */
    public static final int[]     EMPTY_INT_ARRAY            = new int[0];
    public static final Integer[] EMPTY_INTEGER_OBJECT_ARRAY = new Integer[0];

    /** 空的long数组。 */
    public static final long[] EMPTY_LONG_ARRAY        = new long[0];
    public static final Long[] EMPTY_LONG_OBJECT_ARRAY = new Long[0];

    /** 空的float数组。 */
    public static final float[] EMPTY_FLOAT_ARRAY        = new float[0];
    public static final Float[] EMPTY_FLOAT_OBJECT_ARRAY = new Float[0];

    /** 空的double数组。 */
    public static final double[] EMPTY_DOUBLE_ARRAY        = new double[0];
    public static final Double[] EMPTY_DOUBLE_OBJECT_ARRAY = new Double[0];

    /** 空的char数组。 */
    public static final char[]      EMPTY_CHAR_ARRAY             = new char[0];
    public static final Character[] EMPTY_CHARACTER_OBJECT_ARRAY = new Character[0];

    /** 空的boolean数组。 */
    public static final boolean[] EMPTY_BOOLEAN_ARRAY        = new boolean[0];
    public static final Boolean[] EMPTY_BOOLEAN_OBJECT_ARRAY = new Boolean[0];

    // object arrays

    /** 空的Object数组。 */
    public static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];

    /** 空的Class数组。 */
    public static final Class[] EMPTY_CLASS_ARRAY = new Class[0];

    /** 空的String数组。 */
    public static final String[] EMPTY_STRING_ARRAY = new String[0];

    // =============================================================
    //  对象常量
    // =============================================================

    // 0-valued primitive wrappers
    public static final Byte      BYTE_ZERO   = new Byte((byte) 0);
    public static final Short     SHORT_ZERO  = new Short((short) 0);
    public static final Integer   INT_ZERO    = new Integer(0);
    public static final Long      LONG_ZERO   = new Long(0L);
    public static final Float     FLOAT_ZERO  = new Float(0);
    public static final Double    DOUBLE_ZERO = new Double(0);
    public static final Character CHAR_NULL   = new Character('\0');
    public static final Boolean   BOOL_FALSE  = Boolean.FALSE;

    /** 代表null值的占位对象。 */
    public static final Object NULL_PLACEHOLDER = new NullPlaceholder();

    private final static class NullPlaceholder implements Serializable {
        private static final long serialVersionUID = 7092611880189329093L;

        
        public String toString() {
            return "null";
        }

        private Object readResolve() {
            return NULL_PLACEHOLDER;
        }
    }

    /** 空字符串。 */
    public static final String EMPTY_STRING = "";
}