Added Contract converter + Yaml example

spring-cloud-contract-spec/src/main/groovy/org/springframework/cloud/contract/spec/ContractConverter.java

@@ -0,0 +1,40 @@
+package org.springframework.cloud.contract.spec;
+
+import java.io.File;
+
+/**
+ * Converter to be used to convert FROM {@link File} TO {@link Contract}
+ * and from {@link Contract} to {@link T}
+ *
+ * @param <T> - type to which we want to convert the contract
+ *
+ * @author Marcin Grzejszczak
+ * @since 1.0.3
+ */
+public interface ContractConverter<T> {
+
+	/**
+	 * Should this file be accepted by the converter. Can use the file extension
+	 * to check if the conversion is possible.
+	 *
+	 * @param file - file to be considered for conversion
+	 * @return - {@code true} if the given implementation can convert the file
+	 */
+	boolean isAccepted(File file);
+
+	/**
+	 * Converts the given {@link File} to its {@link Contract} representation
+	 *
+	 * @param file - file to convert
+	 * @return - {@link Contract} representation of the file
+	 */
+	Contract convertFrom(File file);
+
+	/**
+	 * Converts the given {@link Contract} to a {@link T} representation
+	 *
+	 * @param contract - the parsed contract
+	 * @return - {@link T} the type to which we do the conversion
+	 */
+	T convertTo(Contract contract);
+}