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. */ package io.hops.erasure_coding; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.Writable; import org.apache.hadoop.io.WritableFactories; import org.apache.hadoop.io.WritableFactory; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import java.text.SimpleDateFormat; import java.util.Enumeration; import java.util.Properties; /** * Maintains information about one policy */ class PolicyInfo implements Writable { public static final Log LOG = LogFactory.getLog("org.apache.hadoop.raid.protocol.PolicyInfo"); protected static final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); private Path srcPath; // the specified src path private String policyName; // name of policy private String codecId; // the codec used private String description; // A verbose description of this policy private Configuration conf; // Hadoop configuration public static String PROPERTY_PARITY_PATH = "parityPath"; public static String PROPERTY_REPLICATION = "targetReplication"; public static String PROPERTY_PARITY_REPLICATION = "metaReplication"; public static String PROPERTY_COPY = "copy"; private Properties properties; // Policy-dependent properties /** * Create the empty object */ public PolicyInfo() { this.conf = null; this.policyName = ""; this.description = ""; this.srcPath = null; this.properties = new Properties(); } /** * Create the metadata that describes a policy */ public PolicyInfo(String policyName, Configuration conf) { this.conf = conf; this.policyName = policyName; this.description = ""; this.srcPath = null; this.properties = new Properties(); } /** * Copy fields from another PolicyInfo */ public void copyFrom(PolicyInfo other) { if (other.conf != null) { this.conf = other.conf; } if (other.policyName != null && other.policyName.length() > 0) { this.policyName = other.policyName; } if (other.description != null && other.description.length() > 0) { this.description = other.description; } if (other.codecId != null) { this.codecId = other.codecId; } if (other.srcPath != null) { this.srcPath = other.srcPath; } for (Object key : other.properties.keySet()) { String skey = (String) key; this.properties.setProperty(skey, other.properties.getProperty(skey)); } LOG.info(this.policyName + ".codecId " + codecId); LOG.info(this.policyName + ".srcpath " + srcPath); } /** * Sets the input path on which this policy has to be applied */ public void setSrcPath(String in) throws IOException { srcPath = new Path(in); } /** * Set the codec used by this policy */ public void setCodecId(String id) { this.codecId = id; } /** * Set the description of this policy. */ public void setDescription(String des) { this.description = des; } /** * Sets an internal property. * * @param name * property name. * @param value * property value. */ public void setProperty(String name, String value) { properties.setProperty(name, value); } /** * Returns the value of an internal property. * * @param name * property name. */ public String getProperty(String name) { return properties.getProperty(name); } /** * Get the name of this policy. */ public String getName() { return this.policyName; } /** * Get the destination path of this policy. */ public String getCodecId() { return this.codecId; } /** * Get the srcPath */ public Path getSrcPath() { return srcPath; } private String normalizePath(String path) { if (!path.endsWith(Path.SEPARATOR)) { path += Path.SEPARATOR; } return path; } /** * Convert this policy into a printable form */ public String toString() { StringBuffer buff = new StringBuffer(); buff.append("Policy Name:\t" + policyName + " --------------------\n"); buff.append("Source Path:\t" + srcPath + "\n"); buff.append("Codec:\t" + codecId + "\n"); for (Enumeration<?> e = properties.propertyNames(); e.hasMoreElements();) { String name = (String) e.nextElement(); buff.append(name + ":\t" + properties.getProperty(name) + "\n"); } if (description.length() > 0) { int len = Math.min(description.length(), 80); String sub = description.substring(0, len).trim(); sub = sub.replaceAll("\n", " "); buff.append("Description:\t" + sub + "...\n"); } return buff.toString(); } ////////////////////////////////////////////////// // Writable ////////////////////////////////////////////////// static { // register a ctor WritableFactories.setFactory(PolicyInfo.class, new WritableFactory() { public Writable newInstance() { return new PolicyInfo(); } }); } public void write(DataOutput out) throws IOException { if (srcPath == null) { Text.writeString(out, ""); } else { Text.writeString(out, srcPath.toString()); } Text.writeString(out, policyName); Text.writeString(out, codecId); Text.writeString(out, description); out.writeInt(properties.size()); for (Enumeration<?> e = properties.propertyNames(); e.hasMoreElements();) { String name = (String) e.nextElement(); Text.writeString(out, name); Text.writeString(out, properties.getProperty(name)); } } public void readFields(DataInput in) throws IOException { String text = Text.readString(in); if (text.length() == 0) { this.srcPath = null; } else { this.srcPath = new Path(text); } this.policyName = Text.readString(in); this.codecId = Text.readString(in); this.description = Text.readString(in); for (int n = in.readInt(); n > 0; n--) { String name = Text.readString(in); String value = Text.readString(in); properties.setProperty(name, value); } } }