get cpu metrics for multiple processes

bindings/java/src/net/hyperic/sigar/MultiProcCpu.java

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+package net.hyperic.sigar;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import net.hyperic.sigar.ptql.ProcessFinder;
+
+/**
+ * Provide multi process cpu metrics.
+ */
+public class MultiProcCpu extends ProcCpu {
+
+    private int nproc = 0;
+    private static Map ptable = new HashMap();
+
+    static synchronized MultiProcCpu get(Sigar sigar, String query)
+        throws SigarException {
+
+        MultiProcCpu cpu;
+
+        cpu = (MultiProcCpu)ptable.get(query);
+
+        if (cpu == null) {
+            cpu = new MultiProcCpu();
+            cpu.pid = query.hashCode(); //for equals()
+            ptable.put(query, cpu);
+        }
+
+        long timeNow = System.currentTimeMillis() / 1000; //seconds
+        double diff = timeNow - cpu.lastTime;
+        if (diff == 0) {
+            return cpu; //we were just called within < 1 second ago.
+        }
+
+        cpu.lastTime = timeNow;
+
+        long otime = cpu.total;
+
+        cpu.total = 0;
+        cpu.user  = 0;
+        cpu.sys   = 0;
+        cpu.nproc = 0;
+
+        long[] pids = ProcessFinder.find(sigar, query);
+        cpu.nproc = pids.length;
+
+        for (int i=0; i<pids.length; i++) {
+            ProcTime time = sigar.getProcTime(pids[i]);
+            cpu.total += time.total;
+            cpu.user  += time.user;
+            cpu.sys   += time.sys;
+        }
+
+        if (otime == 0) {
+            //XXX could/should pause first time called.
+            return cpu;
+        }
+
+        cpu.percent = ((cpu.total - otime) / diff);
+        if (cpu.percent >= 1.0) {
+            cpu.percent = 0.99;
+        }
+
+        return cpu;
+    }
+
+    /**
+     * @return Processes CPU usage percentage.
+     */
+    public double getPercent() {
+        return this.percent;
+    }
+
+    /**
+     * @return Number of processes matched by query.
+     */
+    public int getProcesses() {
+        return this.nproc;
+    }
+}