Java tutorial
/* * 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 * * 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. */ /* * Created on Apr 28, 2005 * Author: Andrzej Bialecki <ab@getopt.org> * */ package org.apache.nutch.parse; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import org.apache.hadoop.io.VersionMismatchException; import org.apache.hadoop.io.Writable; import org.apache.hadoop.io.WritableUtils; import org.apache.hadoop.conf.Configuration; import org.apache.nutch.metadata.Metadata; /** * @author Andrzej Bialecki <ab@getopt.org> */ public class ParseStatus implements Writable { private final static byte VERSION = 2; // Primary status codes: /** Parsing was not performed. */ public static final byte NOTPARSED = 0; /** Parsing succeeded. */ public static final byte SUCCESS = 1; /** General failure. There may be a more specific error message in arguments. */ public static final byte FAILED = 2; public static final String[] majorCodes = { "notparsed", "success", "failed" }; // Secondary success codes go here: /** Parsed content contains a directive to redirect to another URL. * The target URL can be retrieved from the arguments. */ public static final short SUCCESS_REDIRECT = 100; // Secondary failure codes go here: /** Parsing failed. An Exception occured (which may be retrieved from the arguments). */ public static final short FAILED_EXCEPTION = 200; /** Parsing failed. Content was truncated, but the parser cannot handle incomplete content. */ public static final short FAILED_TRUNCATED = 202; /** Parsing failed. Invalid format - the content may be corrupted or of wrong type. */ public static final short FAILED_INVALID_FORMAT = 203; /** Parsing failed. Other related parts of the content are needed to complete * parsing. The list of URLs to missing parts may be provided in arguments. * The Fetcher may decide to fetch these parts at once, then put them into * Content.metadata, and supply them for re-parsing. */ public static final short FAILED_MISSING_PARTS = 204; /** Parsing failed. There was no content to be parsed - probably caused * by errors at protocol stage. */ public static final short FAILED_MISSING_CONTENT = 205; public static final ParseStatus STATUS_NOTPARSED = new ParseStatus(NOTPARSED); public static final ParseStatus STATUS_SUCCESS = new ParseStatus(SUCCESS); public static final ParseStatus STATUS_FAILURE = new ParseStatus(FAILED); private byte majorCode = 0; private short minorCode = 0; private String[] args = null; public byte getVersion() { return VERSION; } public ParseStatus() { } public ParseStatus(int majorCode, int minorCode, String[] args) { this.args = args; this.majorCode = (byte) majorCode; this.minorCode = (short) minorCode; } public ParseStatus(int majorCode) { this(majorCode, 0, (String[]) null); } public ParseStatus(int majorCode, String[] args) { this(majorCode, 0, args); } public ParseStatus(int majorCode, int minorCode) { this(majorCode, minorCode, (String[]) null); } /** Simplified constructor for passing just a text message. */ public ParseStatus(int majorCode, int minorCode, String message) { this(majorCode, minorCode, new String[] { message }); } /** Simplified constructor for passing just a text message. */ public ParseStatus(int majorCode, String message) { this(majorCode, 0, new String[] { message }); } public ParseStatus(Throwable t) { this(FAILED, FAILED_EXCEPTION, new String[] { t.toString() }); } public static ParseStatus read(DataInput in) throws IOException { ParseStatus res = new ParseStatus(); res.readFields(in); return res; } public void readFields(DataInput in) throws IOException { byte version = in.readByte(); switch (version) { case 1: majorCode = in.readByte(); minorCode = in.readShort(); args = WritableUtils.readCompressedStringArray(in); break; case 2: majorCode = in.readByte(); minorCode = in.readShort(); args = WritableUtils.readStringArray(in); break; default: throw new VersionMismatchException(VERSION, version); } } public void write(DataOutput out) throws IOException { out.writeByte(VERSION); out.writeByte(majorCode); out.writeShort(minorCode); if (args == null) { out.writeInt(-1); } else { WritableUtils.writeStringArray(out, args); } } /** A convenience method. Returns true if majorCode is SUCCESS, false * otherwise. */ public boolean isSuccess() { return majorCode == SUCCESS; } /** A convenience method. Return a String representation of the first * argument, or null. */ public String getMessage() { if (args != null && args.length > 0 && args[0] != null) return args[0]; return null; } public String[] getArgs() { return args; } public int getMajorCode() { return majorCode; } public int getMinorCode() { return minorCode; } /** A convenience method. Creates an empty Parse instance, * which returns this status. */ public Parse getEmptyParse(Configuration conf) { return new EmptyParseImpl(this, conf); } /** A convenience method. Creates an empty ParseResult, * which contains this status. */ public ParseResult getEmptyParseResult(String url, Configuration conf) { return ParseResult.createParseResult(url, getEmptyParse(conf)); } public String toString() { StringBuffer res = new StringBuffer(); String name = null; if (majorCode >= 0 && majorCode < majorCodes.length) name = majorCodes[majorCode]; else name = "UNKNOWN!"; res.append(name + "(" + majorCode + "," + minorCode + ")"); if (args != null) { if (args.length == 1) { res.append(": " + String.valueOf(args[0])); } else { for (int i = 0; i < args.length; i++) { if (args[i] != null) res.append(", args[" + i + "]=" + String.valueOf(args[i])); } } } return res.toString(); } public void setArgs(String[] args) { this.args = args; } public void setMessage(String msg) { if (args == null || args.length == 0) { args = new String[1]; } args[0] = msg; } public void setMajorCode(byte majorCode) { this.majorCode = majorCode; } public void setMinorCode(short minorCode) { this.minorCode = minorCode; } public boolean equals(Object o) { if (o == null) return false; if (!(o instanceof ParseStatus)) return false; boolean res = true; ParseStatus other = (ParseStatus) o; res = res && (this.majorCode == other.majorCode) && (this.minorCode == other.minorCode); if (!res) return res; if (this.args == null) { if (other.args == null) return true; else return false; } else { if (other.args == null) return false; if (other.args.length != this.args.length) return false; for (int i = 0; i < this.args.length; i++) { if (!this.args[i].equals(other.args[i])) return false; } } return true; } private static class EmptyParseImpl implements Parse { private ParseData data = null; public EmptyParseImpl(ParseStatus status, Configuration conf) { data = new ParseData(status, "", new Outlink[0], new Metadata(), new Metadata()); } public ParseData getData() { return data; } public String getText() { return ""; } public boolean isCanonical() { return true; } } }