return the String collation key in hex format - Android java.text

Android examples for java.text:Collator

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Description

return the String collation key in hex format

Demo Code

/*//  w  w w .j  ava 2 s. c o m
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * 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 com.book2s;

import java.text.Collator;

public class Main {
    /**
     * Used building output as Hex
     */
    private static final char[] DIGITS = { '0', '1', '2', '3', '4', '5',
            '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
    private static Collator mColl = null;

    /**
     * return the collation key in hex format
     * @param name
     * @return the collation key in hex format
     */
    public static String getHexCollationKey(String name) {
        byte[] arr = getCollationKeyInBytes(name);
        char[] keys = encodeHex(arr);
        return new String(keys, 0, getKeyLen(arr) * 2);
    }

    private static byte[] getCollationKeyInBytes(String name) {
        if (mColl == null) {
            mColl = Collator.getInstance();
            mColl.setStrength(Collator.PRIMARY);
        }
        return mColl.getCollationKey(name).toByteArray();
    }

    private static char[] encodeHex(byte[] input) {
        int l = input.length;
        char[] out = new char[l << 1];

        // two characters form the hex value.
        for (int i = 0, j = 0; i < l; i++) {
            out[j++] = DIGITS[(0xF0 & input[i]) >>> 4];
            out[j++] = DIGITS[0x0F & input[i]];
        }

        return out;
    }

    private static int getKeyLen(byte[] arr) {
        if (arr[arr.length - 1] != 0) {
            return arr.length;
        } else {
            // remove zero "termination"
            return arr.length - 1;
        }
    }

    /**
     * return the collation key
     * @param name
     * @return the collation key
     */
    public static String getCollationKey(String name) {
        byte[] arr = getCollationKeyInBytes(name);
        try {
            return new String(arr, 0, getKeyLen(arr), "ISO8859_1");
        } catch (Exception ex) {
            return "";
        }
    }
}

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