Java tutorial
/** * Licensed to Cloudera, Inc. under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. Cloudera, Inc. 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 com.cloudera.flume.reporter; import java.io.IOException; import java.io.PrintWriter; import java.io.StringWriter; import java.io.Writer; import java.util.Collections; import java.util.Date; import java.util.HashMap; import java.util.Map; import java.util.SortedMap; import java.util.TreeMap; import java.util.Map.Entry; import org.apache.commons.lang.StringEscapeUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.cloudera.flume.core.Attributes; import com.cloudera.flume.core.EventImpl; import com.cloudera.flume.core.Attributes.Type; import com.google.common.base.Preconditions; /** * Reports are just events that have some helpers for quickly outputting data in * human readable or machine parseable formats. * * For now, we use a convention where a attribute starting with "rpt." is a a * reported field. Later we may include a avro schema or something to include * type information as well. */ public class ReportEvent extends EventImpl { static final Logger LOG = LoggerFactory.getLogger(ReportEvent.class); final public static String R_NAME = "name"; final public static String A_COUNT = "count"; final Map<String, Long> longMetrics = new HashMap<String, Long>(); final Map<String, Double> doubleMetrics = new HashMap<String, Double>(); final Map<String, String> stringMetrics = new HashMap<String, String>(); /** * Set a long-valued metric to supplied value. NOT THREAD SAFE. * * @param name * metric name, null not allowed, if the report previously contained * a mapping for the name the old value is replaced with the new. * @param value * metric value to associate with name * @throws IllegalArgumentException * if illegal arguments provided */ public void setLongMetric(String name, long value) { Preconditions.checkArgument(name != null); longMetrics.put(name, value); } /** * Set a double-valued metric to supplied value. NOT THREAD SAFE. * * @param name * metric name, null not allowed, if the report previously contained * a mapping for the name the old value is replaced with the new. * @param value * metric value to associate with name * @throws IllegalArgumentException * if illegal arguments provided */ public void setDoubleMetric(String name, double value) { Preconditions.checkArgument(name != null); doubleMetrics.put(name, value); } /** * Set a string-valued metric to supplied value. NOT THREAD SAFE. * * @param name * metric name, null not allowed, if the report previously contained * a mapping for the name the old value is replaced with the new. * @param value * metric value to associate with name. Null values will be ignored * (not included in the report). * @throws IllegalArgumentException * if illegal arguments provided */ public void setStringMetric(String name, String value) { Preconditions.checkArgument(name != null); if (value != null) { stringMetrics.put(name, value); } else if (LOG.isDebugEnabled()) { // TODO we should look for this during testing and address LOG.debug("Ignoring null string metric " + name); } } /** * Returns the value of a long-valued metric. NOT THREAD SAFE. * * @param name * metric name, null not allowed * @throws IllegalArgumentException * if illegal arguments provided */ public Long getLongMetric(String name) { Preconditions.checkArgument(name != null); return longMetrics.get(name); } /** * Returns the value of a double-valued metric. NOT THREAD SAFE. * * @param name * metric name, null not allowed * @throws IllegalArgumentException * if illegal arguments provided */ public Double getDoubleMetric(String name) { Preconditions.checkArgument(name != null); return doubleMetrics.get(name); } /** * Returns the value of a string-valued metric. NOT THREAD SAFE. * * @param name * metric name, null not allowed * @throws IllegalArgumentException * if illegal arguments provided */ public String getStringMetric(String name) { Preconditions.checkArgument(name != null); return stringMetrics.get(name); } /** * Returns an unmodifiable map of all double metrics */ public Map<String, Double> getAllDoubleMetrics() { return Collections.unmodifiableMap(doubleMetrics); } /** * Returns an unmodifiable map of all string metrics */ public Map<String, String> getAllStringMetrics() { return Collections.unmodifiableMap(stringMetrics); } /** * Returns an unmodifiable map of all long metrics */ public Map<String, Long> getAllLongMetrics() { return Collections.unmodifiableMap(longMetrics); } /** * Returns the total number of metrics. NOT THREAD SAFE. */ public long getNumMetrics() { return this.doubleMetrics.size() + this.longMetrics.size() + this.stringMetrics.size(); } /** * Constructs a copy of event e */ public ReportEvent(ReportEvent e) { super(new byte[0]); Preconditions.checkNotNull(e); this.merge(e); } public ReportEvent(String src) { super(new byte[0]); // empty body this.setStringMetric(R_NAME, src); } /** * Construct a ReportEvent given various metrics. */ public ReportEvent(Map<String, Long> longMetrics, Map<String, String> stringMetrics, Map<String, Double> doubleMetrics) { super(new byte[0]); this.longMetrics.putAll(longMetrics); this.stringMetrics.putAll(stringMetrics); this.doubleMetrics.putAll(doubleMetrics); } /** * Serialises event as JSON string */ public void toJson(Writer o) throws IOException { PrintWriter pw = new PrintWriter(o); pw.print("{"); // an inconsistency: Some of the "attributes" are not in the attribute hash // table -- time, priority, host, body. pw.print("\"host\" : \"" + StringEscapeUtils.escapeJava(getHost()) + "\""); // get the attributes and output them for (String attr : getAttrs().keySet()) { String v = Attributes.toStringStrict(this, attr); Type t = Attributes.getType(attr); pw.print(", \"" + StringEscapeUtils.escapeJava(attr) + "\" : "); if (t != null && t == Type.STRING) { pw.print("\"" + StringEscapeUtils.escapeJava(v) + "\""); } else { pw.print(StringEscapeUtils.escapeJava(v)); } } for (Entry<String, String> entry : getAllStringMetrics().entrySet()) { pw.print(", \"" + StringEscapeUtils.escapeJava(entry.getKey()) + "\" : "); pw.print("\"" + StringEscapeUtils.escapeJava(entry.getValue()) + "\""); } for (Entry<String, Double> entry : getAllDoubleMetrics().entrySet()) { pw.print(", \"" + StringEscapeUtils.escapeJava(entry.getKey()) + "\" : "); pw.print(entry.getValue()); } for (Entry<String, Long> entry : getAllLongMetrics().entrySet()) { pw.print(", \"" + StringEscapeUtils.escapeJava(entry.getKey()) + "\" : "); pw.print(entry.getValue()); } pw.println("}"); } /** * Defaults to printing data out as a bunch of html table cells. */ public void toHtml(Writer o) throws IOException { PrintWriter pw = new PrintWriter(o); pw.print("<table>"); pw.print("<tr>"); pw.print("<th>host</th>"); pw.print("<td>"); pw.print(getHost()); pw.println("</td>"); pw.print("</tr>"); // get the attributes, filter, sort and output them SortedMap<String, String> reportAttrs = new TreeMap<String, String>(); for (String attr : getAttrs().keySet()) { reportAttrs.put(attr, Attributes.toString(this, attr)); } for (Entry<String, Long> e : getAllLongMetrics().entrySet()) { reportAttrs.put(e.getKey(), e.getValue().toString()); } for (Entry<String, Double> e : getAllDoubleMetrics().entrySet()) { reportAttrs.put(e.getKey(), e.getValue().toString()); } for (Entry<String, String> e : getAllStringMetrics().entrySet()) { reportAttrs.put(e.getKey(), e.getValue()); } for (Entry<String, String> a : reportAttrs.entrySet()) { pw.println("<tr><th>" + a.getKey() + "</th>"); pw.print("<td>"); pw.print("<div class=\"" + a.getKey() + "\">"); pw.print(a.getValue()); pw.print("</div>"); pw.println("</td>"); pw.println("</tr>"); } pw.print("</table>"); } /** * Returns event in string form: host [ priority date ] {attr1:val1} * {attr2:val2} {metric1:val1} {metric2:val2} body */ public String toString() { StringBuilder metrics = new StringBuilder(); // Iterate over strings, doubles and longs building a { key : value } string SortedMap<String, String> sortedStrings = new TreeMap<String, String>(this.getAllStringMetrics()); for (Entry<String, String> e : sortedStrings.entrySet()) { metrics.append("{ " + e.getKey() + " : "); String o = e.getValue(); metrics.append(o + " } "); } SortedMap<String, Double> sortedDoubles = new TreeMap<String, Double>(this.getAllDoubleMetrics()); for (Entry<String, Double> e : sortedDoubles.entrySet()) { metrics.append("{ " + e.getKey() + " : "); String o = e.getValue().toString(); metrics.append(o + " } "); } SortedMap<String, Long> sortedLongs = new TreeMap<String, Long>(this.getAllLongMetrics()); for (Entry<String, Long> e : sortedLongs.entrySet()) { metrics.append("{ " + e.getKey() + " : "); String o = e.getValue().toString(); metrics.append(o + " } "); } // This implementation taken from EventImpl String mbody = StringEscapeUtils.escapeJava(new String(getBody())); StringBuilder attrs = new StringBuilder(); SortedMap<String, byte[]> sorted = new TreeMap<String, byte[]>(this.fields); for (Entry<String, byte[]> e : sorted.entrySet()) { attrs.append("{ " + e.getKey() + " : "); String o = Attributes.toString(this, e.getKey()); attrs.append(o + " } "); } return getHost() + " [" + getPriority().toString() + " " + new Date(getTimestamp()) + "] " + attrs.toString() + metrics.toString() + mbody; } /** * Serialises event as text to supplied writer. */ public void toText(Writer o) throws IOException { o.write(StringEscapeUtils.escapeJava(this.toString())); } /** * Legacy report takes a arbitrary string and turns in into a report. */ static class LegacyReport extends ReportEvent { static final String ATTR_LEGACY = "report.legacy.html"; static { Attributes.register(ATTR_LEGACY, Type.STRING); } LegacyReport(String s, byte[] data) { super(s); set(ATTR_LEGACY, data); } public void toHtml(Writer w) { PrintWriter pw = new PrintWriter(w); byte[] data = get(ATTR_LEGACY); pw.print(new String(data)); } } /** * This is a temporary method present while I convert old reports into new * ones. */ public static ReportEvent createLegacyHtmlReport(String name, String data) { return new LegacyReport(name, data.getBytes()); } /** * Does the work for the merge methods by iterating over the set of metrics in * e and copying them to this event with a prefix. */ protected void mergeWithPrefix(String prefix, ReportEvent e) { for (Entry<String, Double> entry : e.getAllDoubleMetrics().entrySet()) { String newKey = prefix + entry.getKey(); if (getDoubleMetric(newKey) == null) { setDoubleMetric(newKey, entry.getValue()); } } for (Entry<String, String> entry : e.getAllStringMetrics().entrySet()) { String newKey = prefix + entry.getKey(); if (getStringMetric(newKey) == null) { setStringMetric(newKey, entry.getValue()); } } for (Entry<String, Long> entry : e.getAllLongMetrics().entrySet()) { String newKey = prefix + entry.getKey(); if (getLongMetric(newKey) == null) { setLongMetric(newKey, entry.getValue()); } } } /** * This method merges in values from other events that are not present in the * current event. */ public void merge(ReportEvent e) { super.merge(e); mergeWithPrefix("", e); } /** * This method "hierarchically" merges the attributes of another event * prefixing each attribute with the specified prefix. * * So if our current event has attributes (a,b,c), and the one being merged in * has attributes (d,e,f), and we have prefix be x, the result event will have * attributes (a,b,c, x.d, x.e, x.f) * * This can be recursive, so if if d was actually an event with (h,i,j) and * prefix in that call is y, we could end up with (a,b,c,x.d,x.e, x.f, x.y.h, * x.y.i, x.y.j) */ public void hierarchicalMerge(String prefix, ReportEvent e) { // Copy the attributes super.hierarchicalMerge(prefix, e); // Copy the metrics mergeWithPrefix(prefix + ".", e); } /** * Return escaped String serialisation of this event */ public String toText() { return StringEscapeUtils.escapeJava(this.toString()); } /** * Return event as JSON string * * Use ReportUtil.toJSONObject instead of this method */ @Deprecated public String toJson() { StringWriter sw = new StringWriter(); try { toJson(sw); } catch (IOException e) { LOG.error("String writer should never throw IOException", e); return null; } return sw.getBuffer().toString(); } /** * Returns event as HTML string */ public String toHtml() { StringWriter sw = new StringWriter(); try { toHtml(sw); } catch (IOException e) { LOG.error("String writer should never throw IOException", e); return null; } return sw.getBuffer().toString(); } }