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diff --git a/bordeaux/learning/predictor_histogram/java/android/bordeaux/learning/predictorHist.java b/bordeaux/learning/predictor_histogram/java/android/bordeaux/learning/predictorHist.java
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+/*
+ * Copyright (C) 2011 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 android.bordeaux.learning;
+
+import java.util.HashMap;
+import java.util.Map;
+import android.util.Log;
+
+/**
+ * A simple impelentation of histograms with sparse enteries using HashMap.
+ * User can push examples or extract probabilites from this histogram.
+ */
+public class predictorHist {
+    private HashMap<String, Integer> mCountHist;
+    private int mSampleCount;
+    String TAG = "PredicrtHist";
+
+    public predictorHist() {
+        mCountHist = new HashMap<String, Integer>();
+        mSampleCount = 0;
+    }
+
+    // reset histogram
+    public void ResetPredictorHist() {
+        mCountHist.clear();
+        mSampleCount = 0;
+    }
+
+    // getters
+    public final HashMap<String, Integer> getHist() {
+        return mCountHist;
+    }
+
+    public int getHistCounts() {
+        return mSampleCount;
+    }
+
+    //setter
+    public void set(HashMap<String, Integer> hist) {
+        ResetPredictorHist();
+        for (Map.Entry<String, Integer> x : hist.entrySet()) {
+            mCountHist.put(x.getKey(), x.getValue());
+            mSampleCount = mSampleCount + x.getValue();
+        }
+    }
+
+    /**
+     * pushes a new example to the histogram
+     */
+    public void pushSample( String fs) {
+        int histValue = 1;
+        if (mCountHist.get(fs) != null )
+            histValue = histValue + mCountHist.get(fs);
+        mCountHist.put(fs,histValue);
+        mSampleCount++;
+    }
+
+    /**
+     * return probabilty of an exmple using the histogram
+     */
+    public float getProbability(String fs) {
+        float res = 0;
+        if (mCountHist.get(fs) != null )
+            res = ((float) mCountHist.get(fs)) / ((float)mSampleCount);
+        return res;
+    }
+}