Android example source code file (FastXmlSerializer.java)

This example Android source code file (FastXmlSerializer.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

buffer_len, buffer_len-1, bytebuffer, escape_table, illegalargumentexception, illegalcharsetnameexception, illegalstateexception, io, ioexception, nio, object, outputstreamwriter, string, unsupportedencodingexception, unsupportedoperationexception, xmlserializer

The FastXmlSerializer.java Android example source code

/*
 * 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.android.internal.util;

import org.xmlpull.v1.XmlSerializer;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;

/**
 * This is a quick and dirty implementation of XmlSerializer that isn't horribly
 * painfully slow like the normal one.  It only does what is needed for the
 * specific XML files being written with it.
 */
public class FastXmlSerializer implements XmlSerializer {
    private static final String ESCAPE_TABLE[] = new String[] {
        null,     null,     null,     null,     null,     null,     null,     null,  // 0-7
        null,     null,     null,     null,     null,     null,     null,     null,  // 8-15
        null,     null,     null,     null,     null,     null,     null,     null,  // 16-23
        null,     null,     null,     null,     null,     null,     null,     null,  // 24-31
        null,     null,     """, null,     null,     null,     "&",  null,  // 32-39
        null,     null,     null,     null,     null,     null,     null,     null,  // 40-47
        null,     null,     null,     null,     null,     null,     null,     null,  // 48-55
        null,     null,     null,     null,     "<",   null,     ">",   null,  // 56-63
    };

    private static final int BUFFER_LEN = 8192;

    private final char[] mText = new char[BUFFER_LEN];
    private int mPos;

    private Writer mWriter;

    private OutputStream mOutputStream;
    private CharsetEncoder mCharset;
    private ByteBuffer mBytes = ByteBuffer.allocate(BUFFER_LEN);

    private boolean mInTag;

    private void append(char c) throws IOException {
        int pos = mPos;
        if (pos >= (BUFFER_LEN-1)) {
            flush();
            pos = mPos;
        }
        mText[pos] = c;
        mPos = pos+1;
    }

    private void append(String str, int i, final int length) throws IOException {
        if (length > BUFFER_LEN) {
            final int end = i + length;
            while (i < end) {
                int next = i + BUFFER_LEN;
                append(str, i, next<end ? BUFFER_LEN : (end-i));
                i = next;
            }
            return;
        }
        int pos = mPos;
        if ((pos+length) > BUFFER_LEN) {
            flush();
            pos = mPos;
        }
        str.getChars(i, i+length, mText, pos);
        mPos = pos + length;
    }

    private void append(char[] buf, int i, final int length) throws IOException {
        if (length > BUFFER_LEN) {
            final int end = i + length;
            while (i < end) {
                int next = i + BUFFER_LEN;
                append(buf, i, next<end ? BUFFER_LEN : (end-i));
                i = next;
            }
            return;
        }
        int pos = mPos;
        if ((pos+length) > BUFFER_LEN) {
            flush();
            pos = mPos;
        }
        System.arraycopy(buf, i, mText, pos, length);
        mPos = pos + length;
    }

    private void append(String str) throws IOException {
        append(str, 0, str.length());
    }

    private void escapeAndAppendString(final String string) throws IOException {
        final int N = string.length();
        final char NE = (char)ESCAPE_TABLE.length;
        final String[] escapes = ESCAPE_TABLE;
        int lastPos = 0;
        int pos;
        for (pos=0; pos<N; pos++) {
            char c = string.charAt(pos);
            if (c >= NE) continue;
            String escape = escapes[c];
            if (escape == null) continue;
            if (lastPos < pos) append(string, lastPos, pos-lastPos);
            lastPos = pos + 1;
            append(escape);
        }
        if (lastPos < pos) append(string, lastPos, pos-lastPos);
    }

    private void escapeAndAppendString(char[] buf, int start, int len) throws IOException {
        final char NE = (char)ESCAPE_TABLE.length;
        final String[] escapes = ESCAPE_TABLE;
        int end = start+len;
        int lastPos = start;
        int pos;
        for (pos=start; pos<end; pos++) {
            char c = buf[pos];
            if (c >= NE) continue;
            String escape = escapes[c];
            if (escape == null) continue;
            if (lastPos < pos) append(buf, lastPos, pos-lastPos);
            lastPos = pos + 1;
            append(escape);
        }
        if (lastPos < pos) append(buf, lastPos, pos-lastPos);
    }

    public XmlSerializer attribute(String namespace, String name, String value) throws IOException,
            IllegalArgumentException, IllegalStateException {
        append(' ');
        if (namespace != null) {
            append(namespace);
            append(':');
        }
        append(name);
        append("=\"");

        escapeAndAppendString(value);
        append('"');
        return this;
    }

    public void cdsect(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void comment(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void docdecl(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void endDocument() throws IOException, IllegalArgumentException, IllegalStateException {
        flush();
    }

    public XmlSerializer endTag(String namespace, String name) throws IOException,
            IllegalArgumentException, IllegalStateException {
        if (mInTag) {
            append(" />\n");
        } else {
            append("</");
            if (namespace != null) {
                append(namespace);
                append(':');
            }
            append(name);
            append(">\n");
        }
        mInTag = false;
        return this;
    }

    public void entityRef(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    private void flushBytes() throws IOException {
        int position;
        if ((position = mBytes.position()) > 0) {
            mBytes.flip();
            mOutputStream.write(mBytes.array(), 0, position);
            mBytes.clear();
        }
    }

    public void flush() throws IOException {
        //Log.i("PackageManager", "flush mPos=" + mPos);
        if (mPos > 0) {
            if (mOutputStream != null) {
                CharBuffer charBuffer = CharBuffer.wrap(mText, 0, mPos);
                CoderResult result = mCharset.encode(charBuffer, mBytes, true);
                while (true) {
                    if (result.isError()) {
                        throw new IOException(result.toString());
                    } else if (result.isOverflow()) {
                        flushBytes();
                        result = mCharset.encode(charBuffer, mBytes, true);
                        continue;
                    }
                    break;
                }
                flushBytes();
                mOutputStream.flush();
            } else {
                mWriter.write(mText, 0, mPos);
                mWriter.flush();
            }
            mPos = 0;
        }
    }

    public int getDepth() {
        throw new UnsupportedOperationException();
    }

    public boolean getFeature(String name) {
        throw new UnsupportedOperationException();
    }

    public String getName() {
        throw new UnsupportedOperationException();
    }

    public String getNamespace() {
        throw new UnsupportedOperationException();
    }

    public String getPrefix(String namespace, boolean generatePrefix)
            throws IllegalArgumentException {
        throw new UnsupportedOperationException();
    }

    public Object getProperty(String name) {
        throw new UnsupportedOperationException();
    }

    public void ignorableWhitespace(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void processingInstruction(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void setFeature(String name, boolean state) throws IllegalArgumentException,
            IllegalStateException {
        if (name.equals("http://xmlpull.org/v1/doc/features.html#indent-output")) {
            return;
        }
        throw new UnsupportedOperationException();
    }

    public void setOutput(OutputStream os, String encoding) throws IOException,
            IllegalArgumentException, IllegalStateException {
        if (os == null)
            throw new IllegalArgumentException();
        if (true) {
            try {
                mCharset = Charset.forName(encoding).newEncoder();
            } catch (IllegalCharsetNameException e) {
                throw (UnsupportedEncodingException) (new UnsupportedEncodingException(
                        encoding).initCause(e));
            } catch (UnsupportedCharsetException e) {
                throw (UnsupportedEncodingException) (new UnsupportedEncodingException(
                        encoding).initCause(e));
            }
            mOutputStream = os;
        } else {
            setOutput(
                encoding == null
                    ? new OutputStreamWriter(os)
                    : new OutputStreamWriter(os, encoding));
        }
    }

    public void setOutput(Writer writer) throws IOException, IllegalArgumentException,
            IllegalStateException {
        mWriter = writer;
    }

    public void setPrefix(String prefix, String namespace) throws IOException,
            IllegalArgumentException, IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void setProperty(String name, Object value) throws IllegalArgumentException,
            IllegalStateException {
        throw new UnsupportedOperationException();
    }

    public void startDocument(String encoding, Boolean standalone) throws IOException,
            IllegalArgumentException, IllegalStateException {
        append("<?xml version='1.0' encoding='utf-8' standalone='"
                + (standalone ? "yes" : "no") + "' ?>\n");
    }

    public XmlSerializer startTag(String namespace, String name) throws IOException,
            IllegalArgumentException, IllegalStateException {
        if (mInTag) {
            append(">\n");
        }
        append('<');
        if (namespace != null) {
            append(namespace);
            append(':');
        }
        append(name);
        mInTag = true;
        return this;
    }

    public XmlSerializer text(char[] buf, int start, int len) throws IOException,
            IllegalArgumentException, IllegalStateException {
        if (mInTag) {
            append(">");
            mInTag = false;
        }
        escapeAndAppendString(buf, start, len);
        return this;
    }

    public XmlSerializer text(String text) throws IOException, IllegalArgumentException,
            IllegalStateException {
        if (mInTag) {
            append(">");
            mInTag = false;
        }
        escapeAndAppendString(text);
        return this;
    }

}