some patterns are added and google question is added

Author: unknown

.idea/workspace.xml

@@ -0,0 +1,28 @@
+package Iterator.IteratorChannelExample;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public class Channel {
+    private double frequency;
+    private ChannelTypeEnum TYPE;
+
+    public Channel(double freq, ChannelTypeEnum type){
+        this.frequency=freq;
+        this.TYPE=type;
+    }
+
+    public double getFrequency() {
+        return frequency;
+    }
+
+    public ChannelTypeEnum getTYPE() {
+        return TYPE;
+    }
+
+    @Override
+    public String toString(){
+        return "Frequency="+this.frequency+", Type="+this.TYPE;
+    }
+
+}

design/src/Iterator/IteratorChannelExample/Channel.java

@@ -0,0 +1,10 @@
+package Iterator.IteratorChannelExample;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public interface ChannelCollection {
+    public void addChannel(Channel c);
+    public void removeChannel(Channel c);
+    public ChannelIterator iterator(ChannelTypeEnum type);
+}

design/src/Iterator/IteratorChannelExample/ChannelCollection.java

@@ -0,0 +1,32 @@
+package Iterator.IteratorChannelExample;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public class ChannelCollectionImpl implements ChannelCollection {
+
+
+    private List<Channel> channelList;
+
+    public ChannelCollectionImpl() {
+        channelList = new ArrayList<Channel>();
+    }
+
+    @Override
+    public void addChannel(Channel c) {
+        channelList.add(c);
+    }
+
+    @Override
+    public void removeChannel(Channel c) {
+        channelList.remove(c);
+    }
+
+    @Override
+    public ChannelIterator iterator(ChannelTypeEnum type) {
+        return new ChannelIteratorImpl(type, this.channelList);
+    }
+}

design/src/Iterator/IteratorChannelExample/ChannelCollectionImpl.java

@@ -0,0 +1,9 @@
+package Iterator.IteratorChannelExample;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public interface ChannelIterator {
+    boolean hasNext();
+    Channel next();
+}

design/src/Iterator/IteratorChannelExample/ChannelIterator.java

@@ -0,0 +1,38 @@
+package Iterator.IteratorChannelExample;
+
+import java.util.List;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public class ChannelIteratorImpl implements ChannelIterator {
+    private ChannelTypeEnum type;
+    private List<Channel> channels;
+    private int position;
+
+    public ChannelIteratorImpl(ChannelTypeEnum ty,
+                               List<Channel> channelsList) {
+        this.type = ty;
+        this.channels = channelsList;
+    }
+
+    @Override
+    public boolean hasNext() {
+        while (position < channels.size()) {
+            Channel c = channels.get(position);
+            if (c.getTYPE().equals(type) || type.equals(ChannelTypeEnum.ALL)) {
+                return true;
+            } else
+                position++;
+        }
+        return false;
+    }
+
+    @Override
+    public Channel next() {
+        Channel c = channels.get(position);
+        position++;
+        return c;
+    }
+
+}

design/src/Iterator/IteratorChannelExample/ChannelIteratorImpl.java

@@ -0,0 +1,8 @@
+package Iterator.IteratorChannelExample;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public enum ChannelTypeEnum {
+    ENGLISH, HINDI, FRENCH, ALL;
+}

design/src/Iterator/IteratorChannelExample/ChannelTypeEnum.java

@@ -0,0 +1,37 @@
+package Iterator.IteratorChannelExample;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public class IteratorMain {
+
+    public static void main(String[] args) {
+        ChannelCollection channels = populateChannels();
+        ChannelIterator baseIterator = channels.iterator(ChannelTypeEnum.ALL);
+        while (baseIterator.hasNext()) {
+            Channel c = baseIterator.next();
+            System.out.println(c.toString());
+        }
+        System.out.println("******");
+        // Channel Type Iterator
+        ChannelIterator englishIterator = channels.iterator(ChannelTypeEnum.ENGLISH);
+        while (englishIterator.hasNext()) {
+            Channel c = englishIterator.next();
+            System.out.println(c.toString());
+        }
+    }
+
+    private static ChannelCollection populateChannels() {
+        ChannelCollection channels = new ChannelCollectionImpl();
+        channels.addChannel(new Channel(98.5, ChannelTypeEnum.ENGLISH));
+        channels.addChannel(new Channel(99.5, ChannelTypeEnum.HINDI));
+        channels.addChannel(new Channel(100.5, ChannelTypeEnum.FRENCH));
+        channels.addChannel(new Channel(101.5, ChannelTypeEnum.ENGLISH));
+        channels.addChannel(new Channel(102.5, ChannelTypeEnum.HINDI));
+        channels.addChannel(new Channel(103.5, ChannelTypeEnum.FRENCH));
+        channels.addChannel(new Channel(104.5, ChannelTypeEnum.ENGLISH));
+        channels.addChannel(new Channel(105.5, ChannelTypeEnum.HINDI));
+        channels.addChannel(new Channel(106.5, ChannelTypeEnum.FRENCH));
+        return channels;
+    }
+}

design/src/Iterator/IteratorChannelExample/IteratorMain.java

@@ -0,0 +1,28 @@
+package Iterator.IteratorChannelExampleUsingNativeIterator;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public class Channel {
+    private double frequency;
+    private ChannelTypeEnum TYPE;
+
+    public Channel(double freq, ChannelTypeEnum type){
+        this.frequency=freq;
+        this.TYPE=type;
+    }
+
+    public double getFrequency() {
+        return frequency;
+    }
+
+    public ChannelTypeEnum getTYPE() {
+        return TYPE;
+    }
+
+    @Override
+    public String toString(){
+        return "Frequency="+this.frequency+", Type="+this.TYPE;
+    }
+
+}

design/src/Iterator/IteratorChannelExampleUsingNativeIterator/Channel.java

@@ -0,0 +1,12 @@
+package Iterator.IteratorChannelExampleUsingNativeIterator;
+
+import java.util.Iterator;
+
+/**
+ * Created by jihun.im on 2017-04-28.
+ */
+public interface ChannelCollection {
+    public void addChannel(Channel c);
+    public void removeChannel(Channel c);
+    public Iterator iterator(ChannelTypeEnum type);
+}