Added the functionality to execute and parse commands.

	* CommandParser can parse input strings to RequestCommand.
	* CommandQueue will execute all ICommands in a queue.
	* TODO: StreamCommands, database implementation.
	* RequestCommand writes into database.txt

1 files changed, 118 insertions, 0 deletions

diff --git a/src/main/RequestCommand.java b/src/main/RequestCommand.java
new file mode 100644
index 0000000..42ff41b
--- /dev/null
+++ b/src/main/RequestCommand.java
@@ -0,0 +1,118 @@
+package main;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.ArrayList;
+import mining.TwitterApi;
+import mining.TwitterApi.Builder;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/**
+ * Basic contained class for a Pair, because Java doesn't provide this.
+ *
+ * @author Maurice Laveaux
+ */
+class Parameter {
+
+    public Parameter(String variable, String value) {
+        this.variable = variable;
+        this.value = value;
+    }
+
+    public String variable;
+    public String value;
+}
+
+/**
+ * A single request/response command that executes once.
+ *
+ * @author Maurice Laveaux
+ */
+public class RequestCommand implements ICommand {
+
+    /**
+     * The api to execute requests on
+     */
+    private final TwitterApi m_api;
+
+    private final String m_command;
+
+    /**
+     * The list of parameters that are executed
+     */
+    private final ArrayList<Parameter> m_parameters;
+
+    /**
+     * Contruct a RequestCommand that executes the request and writes the
+     * results into a file.
+     *
+     * @param api the main twitter api.
+     * @param command the command of the twitter api f.e. users/show.
+     * @param parameters the parameters for the executed command.
+     */
+    public RequestCommand(TwitterApi api, String command, String[] parameters) {
+        m_api = api;
+        m_command = command;
+
+        m_parameters = new ArrayList();
+
+        if (parameters.length < 1) {
+            throw new IllegalArgumentException("Not enough parameters specified.");
+        }
+
+        for (String param : parameters) {
+            // parse the parameter to a variable with a value.
+            m_parameters.add(parseParam(param));
+        }
+    }
+
+    @Override
+    public void execute() {
+        try {
+            // create the building object with the command.
+            Builder builder = m_api.build(m_command);
+
+            // add every parameter to the builder.
+            for (Parameter param : m_parameters) {
+                builder = builder.param(param.variable, param.value);
+            }
+
+            JSONObject result = builder.request();
+
+            // TODO: add the results to the main database.            
+            // For now write to a file
+            File file = new File("database.txt");
+
+            FileWriter writer = new FileWriter(file, true);
+
+            writer.write("\n\r" + result.toString());
+            writer.flush();
+
+            System.out.println(result.toString(4));
+        } catch (JSONException ex) {
+            /* cannot happen */
+            throw new RuntimeException(ex);
+        } catch (IOException ex) {
+            // TODO: when ratelimit reached, add event back to queue.
+            throw new RuntimeException(ex);
+        }
+    }
+
+    /**
+     * Parses the input string to a parameter.
+     *
+     * @param input A single line in the form variable=value.
+     * @return A pair of strings for variable and value.
+     */
+    private Parameter parseParam(final String input) {
+        String[] seperated = input.split("=");
+
+        if (seperated.length < 2) {
+            throw new IllegalArgumentException("parameter did not contain <variable>=<value>.");
+        }
+
+        return new Parameter(seperated[0], seperated[1]);
+    }
+}