extracted repetitive code for List/Get/Create/Update/Delete into inte…

…rfaces

src/main/java/nl/stil4m/mollie/concepts/AbstractConcept.java

@@ -20,9 +20,10 @@
 import nl.stil4m.mollie.ResponseOrError;
 import nl.stil4m.mollie.domain.Page;
 
-public abstract class AbstractConcept<T extends Object> {
+public abstract class AbstractConcept<T extends Object> implements Concept<T> {
     private static final Collector<CharSequence, ?, String> URL_JOINER = Collectors.joining("/");
     private static final TypeReference<Void> VOID_TYPE_REFERENCE = new TypeReference<Void>(){};
+
     private final TypeReference<Page<T>> pageTypeReference;
     private final TypeReference<T> singleTypeReference;
     private final String apiKey;
@@ -48,26 +49,31 @@ private static String trimToNull(String value) {
         return value!=null && !value.trim().isEmpty()?value.trim():null;
     }
 
-    protected String url(String... elements) {
+    @Override
+    public String url(String... elements) {
         if(elements==null || elements.length==0) {
             return this.endpoint;
         }
         return joinUrl(this.endpoint,joinUrl(elements));
     }
 
-    protected ResponseOrError<Page<T>> requestPage(HttpUriRequest httpRequest) throws IOException {
+    @Override
+    public ResponseOrError<Page<T>> requestPage(HttpUriRequest httpRequest) throws IOException {
         return requestExecutor.execute(apiKey, httpRequest, pageTypeReference);
     }
 
-    protected ResponseOrError<T> requestSingle(HttpUriRequest httpRequest) throws IOException {
+    @Override
+    public ResponseOrError<T> requestSingle(HttpUriRequest httpRequest) throws IOException {
         return requestExecutor.execute(apiKey, httpRequest, singleTypeReference);
     }
 
-    protected ResponseOrError<Void> requestVoid(HttpUriRequest httpRequest) throws IOException {
+    @Override
+    public ResponseOrError<Void> requestVoid(HttpUriRequest httpRequest) throws IOException {
         return requestExecutor.execute(apiKey, httpRequest, VOID_TYPE_REFERENCE);
     }
 
-    protected HttpEntity buildHttpEntity(Object value) throws UnsupportedCharsetException, JsonProcessingException {
+    @Override
+    public HttpEntity buildHttpEntity(Object value) throws UnsupportedCharsetException, JsonProcessingException {
         return new StringEntity(requestExecutor.serialize(value), ContentType.APPLICATION_JSON);
     }
 }

src/main/java/nl/stil4m/mollie/concepts/Concept.java

@@ -0,0 +1,24 @@
+package nl.stil4m.mollie.concepts;
+
+import java.io.IOException;
+import java.nio.charset.UnsupportedCharsetException;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.client.methods.HttpUriRequest;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+
+import nl.stil4m.mollie.ResponseOrError;
+import nl.stil4m.mollie.domain.Page;
+
+public interface Concept<T extends Object> {
+    String url(String... elements);
+
+    ResponseOrError<Page<T>> requestPage(HttpUriRequest get) throws IOException;
+
+    ResponseOrError<T> requestSingle(HttpUriRequest get) throws IOException;
+
+    ResponseOrError<Void> requestVoid(HttpUriRequest get) throws IOException;
+
+    HttpEntity buildHttpEntity(Object value) throws UnsupportedCharsetException, JsonProcessingException;
+}

src/main/java/nl/stil4m/mollie/concepts/Create.java

@@ -0,0 +1,16 @@
+package nl.stil4m.mollie.concepts;
+
+import java.io.IOException;
+
+import org.apache.http.client.methods.HttpPost;
+
+import nl.stil4m.mollie.ResponseOrError;
+
+public interface Create<R extends Object,O extends Object> extends Concept<R> {
+
+    default ResponseOrError<R> create(O create) throws IOException {
+        HttpPost httpPost = new HttpPost(url());
+        httpPost.setEntity(buildHttpEntity(create));
+        return requestSingle(httpPost);
+    }
+}

src/main/java/nl/stil4m/mollie/concepts/CustomerPayments.java

@@ -1,41 +1,12 @@
 package nl.stil4m.mollie.concepts;
 
-import java.io.IOException;
-import java.net.URISyntaxException;
-import java.util.Optional;
-
-import org.apache.http.client.methods.HttpGet;
-import org.apache.http.client.methods.HttpPost;
-import org.apache.http.client.utils.URIBuilder;
-
-import com.fasterxml.jackson.core.type.TypeReference;
-
 import nl.stil4m.mollie.RequestExecutor;
-import nl.stil4m.mollie.ResponseOrError;
 import nl.stil4m.mollie.domain.CustomerPayment;
-import nl.stil4m.mollie.domain.Page;
 import nl.stil4m.mollie.domain.Payment;
 
-public class CustomerPayments extends AbstractConcept<Payment> {
-    private static final TypeReference<Page<Payment>> PAGE_TYPE = new TypeReference<Page<Payment>>() {};
-    private static final TypeReference<Payment> SINGLE_TYPE = new TypeReference<Payment>() {};
+public class CustomerPayments extends AbstractConcept<Payment> implements ListAll<Payment>,Create<Payment,CustomerPayment> {
 
     public CustomerPayments(String apiKey, String endpoint, RequestExecutor requestExecutor, String customerId) {
-        super(apiKey,requestExecutor,SINGLE_TYPE,PAGE_TYPE,endpoint,"customers",customerId,"payments");
-    }
-
-    public ResponseOrError<Page<Payment>> all(Optional<Object> count, Optional<Object> offset) throws URISyntaxException, IOException {
-        URIBuilder builder = new URIBuilder(url())
-                .setParameter("count", String.valueOf(count.orElse(10)))
-                .setParameter("offset", String.valueOf(offset.orElse(0)));
-
-        HttpGet httpGet = new HttpGet(builder.build());
-        return requestPage(httpGet);
-    }
-
-    public ResponseOrError<Payment> create(CustomerPayment customerPayment) throws IOException {
-        HttpPost httpPost = new HttpPost(url());
-        httpPost.setEntity(buildHttpEntity(customerPayment));
-        return requestSingle(httpPost);
+        super(apiKey,requestExecutor,Payments.SINGLE_TYPE,Payments.PAGE_TYPE,endpoint,"customers",customerId,"payments");
     }
 }

src/main/java/nl/stil4m/mollie/concepts/Customers.java

@@ -1,53 +1,18 @@
 package nl.stil4m.mollie.concepts;
 
-import java.io.IOException;
-import java.net.URISyntaxException;
-import java.util.Optional;
-
-import org.apache.http.client.methods.HttpGet;
-import org.apache.http.client.methods.HttpPost;
-import org.apache.http.client.utils.URIBuilder;
-
 import com.fasterxml.jackson.core.type.TypeReference;
 
 import nl.stil4m.mollie.RequestExecutor;
-import nl.stil4m.mollie.ResponseOrError;
 import nl.stil4m.mollie.domain.CreateCustomer;
 import nl.stil4m.mollie.domain.Customer;
 import nl.stil4m.mollie.domain.Page;
 import nl.stil4m.mollie.domain.UpdateCustomer;
 
-public class Customers extends AbstractConcept<Customer> {
+public class Customers extends AbstractConcept<Customer> implements ListAll<Customer>,GetById<Customer>,Create<Customer,CreateCustomer>,Update<Customer,UpdateCustomer> {
     private static final TypeReference<Page<Customer>> PAGE_TYPE = new TypeReference<Page<Customer>>() {};
     private static final TypeReference<Customer> SINGLE_TYPE = new TypeReference<Customer>() {};
 
     public Customers(String apiKey, String endpoint, RequestExecutor requestExecutor) {
         super(apiKey,requestExecutor,SINGLE_TYPE,PAGE_TYPE,endpoint,"customers");
     }
-
-    public ResponseOrError<Customer> create(CreateCustomer createCustomer) throws IOException {
-        HttpPost httpPost = new HttpPost(url());
-        httpPost.setEntity(buildHttpEntity(createCustomer));
-        return requestSingle(httpPost);
-    }
-
-    public ResponseOrError<Customer> update(String customerId, UpdateCustomer updateCustomer) throws IOException {
-        HttpPost httpPost = new HttpPost(url(customerId));
-        httpPost.setEntity(buildHttpEntity(updateCustomer));
-        return requestSingle(httpPost);
-    }
-
-    public ResponseOrError<Page<Customer>> all(Optional<Integer> count, Optional<Integer> offset) throws IOException, URISyntaxException {
-        URIBuilder builder = new URIBuilder(url())
-                .setParameter("count", String.valueOf(count.orElse(10)))
-                .setParameter("offset", String.valueOf(offset.orElse(0)));
-
-        HttpGet httpGet = new HttpGet(builder.build());
-        return requestPage(httpGet);
-    }
-
-    public ResponseOrError<Customer> get(String id) throws IOException {
-        HttpGet httpGet = new HttpGet(url(id));
-        return requestSingle(httpGet);
-    }
 }

src/main/java/nl/stil4m/mollie/concepts/Delete.java

@@ -0,0 +1,15 @@
+package nl.stil4m.mollie.concepts;
+
+import java.io.IOException;
+
+import org.apache.http.client.methods.HttpDelete;
+
+import nl.stil4m.mollie.ResponseOrError;
+
+public interface Delete<T extends Object> extends Concept<T> {
+
+    default ResponseOrError<Void> delete(String id) throws IOException {
+        HttpDelete httpDelete = new HttpDelete(url(id));
+        return requestVoid(httpDelete);
+    }
+}

src/main/java/nl/stil4m/mollie/concepts/GetById.java

@@ -0,0 +1,15 @@
+package nl.stil4m.mollie.concepts;
+
+import java.io.IOException;
+
+import org.apache.http.client.methods.HttpGet;
+
+import nl.stil4m.mollie.ResponseOrError;
+
+public interface GetById<T extends Object> extends Concept<T> {
+
+    default ResponseOrError<T> get(String id) throws IOException {
+        HttpGet httpGet = new HttpGet(url(id));
+        return requestSingle(httpGet);
+    }
+}

src/main/java/nl/stil4m/mollie/concepts/Issuers.java

@@ -1,39 +1,16 @@
 package nl.stil4m.mollie.concepts;
 
-import java.io.IOException;
-import java.net.URISyntaxException;
-import java.util.Optional;
-
-import org.apache.http.client.methods.HttpGet;
-import org.apache.http.client.utils.URIBuilder;
-
 import com.fasterxml.jackson.core.type.TypeReference;
 
 import nl.stil4m.mollie.RequestExecutor;
-import nl.stil4m.mollie.ResponseOrError;
 import nl.stil4m.mollie.domain.Issuer;
 import nl.stil4m.mollie.domain.Page;
 
-public class Issuers extends AbstractConcept<Issuer> {
+public class Issuers extends AbstractConcept<Issuer> implements ListAll<Issuer>,GetById<Issuer> {
     private static final TypeReference<Page<Issuer>> PAGE_TYPE = new TypeReference<Page<Issuer>>() {};
     private static final TypeReference<Issuer> SINGLE_TYPE = new TypeReference<Issuer>() {};
-
 
     public Issuers(String apiKey, String endpoint, RequestExecutor requestExecutor) {
         super(apiKey,requestExecutor,SINGLE_TYPE,PAGE_TYPE,endpoint,"issuers");
     }
-
-    public ResponseOrError<Page<Issuer>> all(Optional<Integer> count, Optional<Integer> offset) throws IOException, URISyntaxException {
-        URIBuilder builder = new URIBuilder(url())
-                .setParameter("count", String.valueOf(count.orElse(10)))
-                .setParameter("offset", String.valueOf(offset.orElse(0)));
-
-        HttpGet httpGet = new HttpGet(builder.build());
-        return requestPage(httpGet);
-    }
-
-    public ResponseOrError<Issuer> get(String id) throws IOException {
-        HttpGet httpGet = new HttpGet(url(id));
-        return requestSingle(httpGet);
-    }
-}
+}

src/main/java/nl/stil4m/mollie/concepts/ListAll.java

@@ -0,0 +1,44 @@
+package nl.stil4m.mollie.concepts;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Optional;
+
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.utils.URIBuilder;
+
+import nl.stil4m.mollie.ResponseOrError;
+import nl.stil4m.mollie.domain.Page;
+import nl.stil4m.mollie.domain.Payment;
+
+public interface ListAll<T extends Object> extends Concept<T> {
+
+    default ResponseOrError<Page<T>> all(Optional<Integer> count, Optional<Integer> offset) throws IOException, URISyntaxException {
+        return list(count,offset);
+    }
+
+    default ResponseOrError<Page<T>> list(Optional<Integer> count, Optional<Integer> offset) throws IOException, URISyntaxException {
+        URIBuilder builder = new URIBuilder(url())
+                .setParameter("count", String.valueOf(count.orElse(10)))
+                .setParameter("offset", String.valueOf(offset.orElse(0)));
+
+        HttpGet httpGet = new HttpGet(builder.build());
+        return requestPage(httpGet);
+    }
+
+    default ResponseOrError<Page<T>> next(Page<Payment> page) throws IOException {
+        if (!page.getLinks().getNext().isPresent()) {
+            throw new IllegalArgumentException("Page does not have next");
+        }
+        HttpGet httpGet = new HttpGet(page.getLinks().getNext().get());
+        return requestPage(httpGet);
+    }
+
+    default ResponseOrError<Page<T>> previous(Page<Payment> page) throws IOException {
+        if (!page.getLinks().getPrevious().isPresent()) {
+            throw new IllegalArgumentException("Page does not have next");
+        }
+        HttpGet httpGet = new HttpGet(page.getLinks().getPrevious().get());
+        return requestPage(httpGet);
+    }
+}