package com.ctc.wstx.util;

Class similar to StringBuilder, except that it can be used to construct multiple Strings, that will share same underlying character buffer. This is generally useful for closely related value Strings, such as attribute values of a single XML start element. /**
 * Class similar to {@link StringBuilder}, except that it can be used to
 * construct multiple Strings, that will share same underlying character
 * buffer. This is generally useful for closely related value Strings,
 * such as attribute values of a single XML start element.
 */
public final class TextBuilder
{
    private final static int MIN_LEN = 60;
    private final static int MAX_LEN = 120;

    private char[] mBuffer;

    private int mBufferLen;

    private String mResultString;

    /*
    ///////////////////////////////////////////////////////////////////////
    // Life-cycle:
    ///////////////////////////////////////////////////////////////////////
     */

    public TextBuilder(int initialSize)
    {
        int charSize = (initialSize << 4); // multiply by 16 (-> def. 192 chars)
        if (charSize < MIN_LEN) {
            charSize = MIN_LEN;
        } else if (charSize > MAX_LEN) {
            charSize = MAX_LEN;
        }
        mBuffer = new char[charSize];
    }

    
Method called before starting to (re)use the buffer, will discard
any existing content, and start collecting new set of values.
/**
     * Method called before starting to (re)use the buffer, will discard
     * any existing content, and start collecting new set of values.
     */
    public void reset() {
        mBufferLen = 0;
        mResultString = null;
    }

    /*
    ///////////////////////////////////////////////////////////////////////
    // Accessors
    ///////////////////////////////////////////////////////////////////////
     */

    public boolean isEmpty() {
        return mBufferLen == 0;
    }

    public String getAllValues()
    {
        if (mResultString == null) {
            mResultString = new String(mBuffer, 0, mBufferLen);
        }
        return mResultString;
    }

    
Method that gives access to underlying character buffer
/**
     * Method that gives access to underlying character buffer
     */
    public char[] getCharBuffer() {
        return mBuffer;
    }

    public int getCharSize() {
        return mBufferLen;
    }

    /*
    ///////////////////////////////////////////////////////////////////////
    // Mutators
    ///////////////////////////////////////////////////////////////////////
     */

    public void append(char c) {
        if (mBuffer.length == mBufferLen) {
            resize(1);
        }
        mBuffer[mBufferLen++] = c;
    }

    public void append(char[] src, int start, int len) {
        if (len > (mBuffer.length - mBufferLen)) {
            resize(len);
        }
        System.arraycopy(src, start, mBuffer, mBufferLen, len);
        mBufferLen += len;
    }

    public void setBufferSize(int newSize) {
        mBufferLen = newSize;
    }

    public char[] bufferFull(int needSpaceFor) {
        mBufferLen = mBuffer.length;
        resize(needSpaceFor);
        return mBuffer;
    }

    /*
    ///////////////////////////////////////////////////////////////////////
    // Debug support
    ///////////////////////////////////////////////////////////////////////
     */

    @Override
    public String toString() {
        return new String(mBuffer, 0, mBufferLen);
    }

    /*
    ///////////////////////////////////////////////////////////////////////
    // Internal methodss
    ///////////////////////////////////////////////////////////////////////
     */

    private void resize(int needSpaceFor) {
        char[] old = mBuffer;
        int oldLen = old.length;
        int addition = oldLen >> 1; // Grow by 50%
        needSpaceFor -= (oldLen - mBufferLen);
        if (addition < needSpaceFor) {
            addition = needSpaceFor;
        }
        mBuffer = new char[oldLen+addition];
        System.arraycopy(old, 0, mBuffer, 0, mBufferLen);
    }
}