/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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
 *
 *      https://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 org.apache.tools.ant.util;

import java.io.IOException;
import java.io.Reader;

import org.apache.tools.ant.ProjectComponent;

Class to tokenize the input as areas separated
by white space, or by a specified list of
delim characters. Behaves like java.util.StringTokenizer.
If the stream starts with delim characters, the first
token will be an empty string (unless the treat delims
as tokens flag is set).
Since:
Ant 1.7/**
 * Class to tokenize the input as areas separated
 * by white space, or by a specified list of
 * delim characters. Behaves like java.util.StringTokenizer.
 * If the stream starts with delim characters, the first
 * token will be an empty string (unless the treat delims
 * as tokens flag is set).
 * @since Ant 1.7
 */
public class StringTokenizer extends ProjectComponent implements Tokenizer {
    private static final int NOT_A_CHAR = -2;
    private String intraString = "";
    private int    pushed = NOT_A_CHAR;
    private char[] delims = null;
    private boolean delimsAreTokens = false;
    private boolean suppressDelims = false;
    private boolean includeDelims = false;

    
attribute delims - the delimiter characters
Params:
delims – a string containing the delimiter characters/**
     * attribute delims - the delimiter characters
     * @param delims a string containing the delimiter characters
     */
    public void setDelims(String delims) {
        this.delims = StringUtils.resolveBackSlash(delims).toCharArray();
    }

    
attribute delimsaretokens - treat delimiters as
separate tokens.
Params:
delimsAreTokens – true if delimiters are to be separate/**
     * attribute delimsaretokens - treat delimiters as
     * separate tokens.
     * @param delimsAreTokens true if delimiters are to be separate
     */

    public void setDelimsAreTokens(boolean delimsAreTokens) {
        this.delimsAreTokens = delimsAreTokens;
    }
    
attribute suppressdelims - suppress delimiters.
default - false
Params:
suppressDelims – if true do not report delimiters/**
     * attribute suppressdelims - suppress delimiters.
     * default - false
     * @param suppressDelims if true do not report delimiters
     */
    public void setSuppressDelims(boolean suppressDelims) {
        this.suppressDelims = suppressDelims;
    }

    
attribute includedelims - treat delimiters as part
of the token.
default - false
Params:
includeDelims – if true add delimiters to the token/**
     * attribute includedelims - treat delimiters as part
     * of the token.
     * default - false
     * @param includeDelims if true add delimiters to the token
     */
    public void setIncludeDelims(boolean includeDelims) {
        this.includeDelims = includeDelims;
    }

    
find and return the next token
Params:
in – the input stream
Throws:
IOException – if an error occurs reading
Returns:
the token/**
     * find and return the next token
     *
     * @param in the input stream
     * @return the token
     * @exception IOException if an error occurs reading
     */
    public String getToken(Reader in) throws IOException {
        int ch = -1;
        if (pushed != NOT_A_CHAR) {
            ch = pushed;
            pushed = NOT_A_CHAR;
        } else {
            ch = in.read();
        }
        if (ch == -1) {
            return null;
        }
        boolean inToken = true;
        intraString = "";
        StringBuilder word = new StringBuilder();
        StringBuilder padding = new StringBuilder();
        while (ch != -1) {
            char c = (char) ch;
            boolean isDelim = isDelim(c);
            if (inToken) {
                if (isDelim) {
                    if (delimsAreTokens) {
                        if (word.length() > 0) {
                            pushed = ch;
                        } else {
                            word.append(c);
                        }
                        break;
                    }
                    padding.append(c);
                    inToken = false;
                } else {
                    word.append(c);
                }
            } else if (isDelim) {
                padding.append(c);
            } else {
                pushed = ch;
                break;
            }
            ch = in.read();
        }
        intraString = padding.toString();
        if (includeDelims) {
            word.append(intraString);
        }
        return word.toString();
    }

    
Returns:
the intratoken string/**
     * @return the intratoken string
     */
    @Override
    public String getPostToken() {
        return suppressDelims || includeDelims ? "" : intraString;
    }

    private boolean isDelim(char ch) {
        if (delims == null) {
            return Character.isWhitespace(ch);
        }
        for (char delim : delims) {
            if (delim == ch) {
                return true;
            }
        }
        return false;
    }
}