DATACMNS-350 - Improved extensibility of Parameters.

Parameters is now a class explicitly designed for extension using generics. We provide a new DefaultParameters which is essentially a drop in replacement for former Parameters as it exposes individual Parameter instances.

Modules that previously extended Parameters will now have to implement the abstract factory methods exposed to create concrete - and potentially customized - Parameter instances.

src/main/java/org/springframework/data/repository/query/DefaultParameters.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * 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 org.springframework.data.repository.query;
+
+import java.lang.reflect.Method;
+import java.util.List;
+
+import org.springframework.core.MethodParameter;
+
+/**
+ * Default implementation of {@link Parameters}.
+ * 
+ * @author Oliver Gierke
+ */
+public final class DefaultParameters extends Parameters<DefaultParameters, Parameter> {
+
+	/**
+	 * Creates a new {@link DefaultParameters} instance from the given {@link Method}.
+	 * 
+	 * @param method must not be {@literal null}.
+	 */
+	public DefaultParameters(Method method) {
+		super(method);
+	}
+
+	private DefaultParameters(List<Parameter> parameters) {
+		super(parameters);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.Parameters#createParameter(org.springframework.core.MethodParameter)
+	 */
+	@Override
+	protected Parameter createParameter(MethodParameter parameter) {
+		return new Parameter(parameter);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.Parameters#createFrom(java.util.List)
+	 */
+	@Override
+	protected DefaultParameters createFrom(List<Parameter> parameters) {
+		return new DefaultParameters(parameters);
+	}
+}

src/main/java/org/springframework/data/repository/query/Parameter.java

@@ -32,11 +32,7 @@ import org.springframework.util.Assert;
  */
 public class Parameter {
 
-	@SuppressWarnings("unchecked")
-	static final List<Class<?>> TYPES = Arrays.asList(Pageable.class, Sort.class);
-
-	private static final String PARAM_ON_SPECIAL = format("You must not user @%s on a parameter typed %s or %s",
-			Param.class.getSimpleName(), Pageable.class.getSimpleName(), Sort.class.getSimpleName());
+	@SuppressWarnings("unchecked") static final List<Class<?>> TYPES = Arrays.asList(Pageable.class, Sort.class);
 
 	private static final String NAMED_PARAMETER_TEMPLATE = ":%s";
 	private static final String POSITION_PARAMETER_TEMPLATE = "?%s";
@@ -51,12 +47,7 @@ public class Parameter {
 	protected Parameter(MethodParameter parameter) {
 
 		Assert.notNull(parameter);
-
 		this.parameter = parameter;
-
-		if (isSpecialParameter() && isNamedParameter()) {
-			throw new IllegalArgumentException(PARAM_ON_SPECIAL);
-		}
 	}
 
 	/**

src/main/java/org/springframework/data/repository/query/Parameters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2012 the original author or authors.
+ * Copyright 2008-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
  */
 package org.springframework.data.repository.query;
 
+import static java.lang.String.*;
+
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -33,11 +35,12 @@ import org.springframework.util.Assert;
  * 
  * @author Oliver Gierke
  */
-public class Parameters implements Iterable<Parameter> {
+public abstract class Parameters<S extends Parameters<S, T>, T extends Parameter> implements Iterable<T> {
 
-	@SuppressWarnings("unchecked")
-	public static final List<Class<?>> TYPES = Arrays.asList(Pageable.class, Sort.class);
+	@SuppressWarnings("unchecked") public static final List<Class<?>> TYPES = Arrays.asList(Pageable.class, Sort.class);
 
+	private static final String PARAM_ON_SPECIAL = format("You must not user @%s on a parameter typed %s or %s",
+			Param.class.getSimpleName(), Pageable.class.getSimpleName(), Sort.class.getSimpleName());
 	private static final String ALL_OR_NOTHING = String.format("Either use @%s "
 			+ "on all parameters except %s and %s typed once, or none at all!", Param.class.getSimpleName(),
 			Pageable.class.getSimpleName(), Sort.class.getSimpleName());
@@ -45,7 +48,7 @@ public class Parameters implements Iterable<Parameter> {
 	private final int pageableIndex;
 	private final int sortIndex;
 
-	private final List<Parameter> parameters;
+	private final List<T> parameters;
 	private final ParameterNameDiscoverer discoverer = new LocalVariableTableParameterNameDiscoverer();
 
 	/**
@@ -57,14 +60,22 @@ public class Parameters implements Iterable<Parameter> {
 
 		Assert.notNull(method);
 
-		this.parameters = new ArrayList<Parameter>();
+		this.parameters = new ArrayList<T>();
 
 		List<Class<?>> types = Arrays.asList(method.getParameterTypes());
 
 		for (int i = 0; i < types.size(); i++) {
-			MethodParameter parameter = new MethodParameter(method, i);
-			parameter.initParameterNameDiscovery(discoverer);
-			parameters.add(createParameter(parameter));
+
+			MethodParameter methodParameter = new MethodParameter(method, i);
+			methodParameter.initParameterNameDiscovery(discoverer);
+
+			T parameter = createParameter(methodParameter);
+
+			if (parameter.isSpecialParameter() && parameter.isNamedParameter()) {
+				throw new IllegalArgumentException(PARAM_ON_SPECIAL);
+			}
+
+			parameters.add(parameter);
 		}
 
 		this.pageableIndex = types.indexOf(Pageable.class);
@@ -78,16 +89,16 @@ public class Parameters implements Iterable<Parameter> {
 	 * 
 	 * @param originals
 	 */
-	private Parameters(List<Parameter> originals) {
+	protected Parameters(List<T> originals) {
 
-		this.parameters = new ArrayList<Parameter>();
+		this.parameters = new ArrayList<T>();
 
 		int pageableIndexTemp = -1;
 		int sortIndexTemp = -1;
 
 		for (int i = 0; i < originals.size(); i++) {
 
-			Parameter original = originals.get(i);
+			T original = originals.get(i);
 			this.parameters.add(original);
 
 			pageableIndexTemp = original.isPageable() ? i : -1;
@@ -98,9 +109,13 @@ public class Parameters implements Iterable<Parameter> {
 		this.sortIndex = sortIndexTemp;
 	}
 
-	protected Parameter createParameter(MethodParameter parameter) {
-		return new Parameter(parameter);
-	}
+	/**
+	 * Creates a {@link Parameter} instance for the given {@link MethodParameter}.
+	 * 
+	 * @param parameter will never be {@literal null}.
+	 * @return
+	 */
+	protected abstract T createParameter(MethodParameter parameter);
 
 	/**
 	 * Returns whether the method the {@link Parameters} was created for contains a {@link Pageable} argument.
@@ -108,7 +123,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public boolean hasPageableParameter() {
-
 		return pageableIndex != -1;
 	}
 
@@ -119,7 +133,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return the pageableIndex
 	 */
 	public int getPageableIndex() {
-
 		return pageableIndex;
 	}
 
@@ -130,7 +143,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public int getSortIndex() {
-
 		return sortIndex;
 	}
 
@@ -140,7 +152,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public boolean hasSortParameter() {
-
 		return sortIndex != -1;
 	}
 
@@ -150,7 +161,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public boolean potentiallySortsDynamically() {
-
 		return hasSortParameter() || hasPageableParameter();
 	}
 
@@ -160,7 +170,7 @@ public class Parameters implements Iterable<Parameter> {
 	 * @param index
 	 * @return
 	 */
-	public Parameter getParameter(int index) {
+	public T getParameter(int index) {
 
 		try {
 			return parameters.get(index);
@@ -191,7 +201,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public boolean hasSpecialParameter() {
-
 		return hasSortParameter() || hasPageableParameter();
 	}
 
@@ -201,7 +210,6 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public int getNumberOfParameters() {
-
 		return parameters.size();
 	}
 
@@ -212,20 +220,22 @@ public class Parameters implements Iterable<Parameter> {
 	 * @see Parameter#TYPES
 	 * @see Parameter#isSpecialParameter()
 	 */
-	public Parameters getBindableParameters() {
+	public S getBindableParameters() {
 
-		List<Parameter> bindables = new ArrayList<Parameter>();
+		List<T> bindables = new ArrayList<T>();
 
-		for (Parameter candidate : this) {
+		for (T candidate : this) {
 
 			if (candidate.isBindable()) {
 				bindables.add(candidate);
 			}
 		}
 
-		return new Parameters(bindables);
+		return createFrom(bindables);
 	}
 
+	protected abstract S createFrom(List<T> parameters);
+
 	/**
 	 * Returns a bindable parameter with the given index. So for a method with a signature of
 	 * {@code (Pageable pageable, String name)} a call to {@code #getBindableParameter(0)} will return the {@link String}
@@ -234,8 +244,7 @@ public class Parameters implements Iterable<Parameter> {
 	 * @param bindableIndex
 	 * @return
 	 */
-	public Parameter getBindableParameter(int bindableIndex) {
-
+	public T getBindableParameter(int bindableIndex) {
 		return getBindableParameters().getParameter(bindableIndex);
 	}
 
@@ -249,7 +258,7 @@ public class Parameters implements Iterable<Parameter> {
 
 		boolean nameFound = false;
 
-		for (Parameter parameter : this.getBindableParameters()) {
+		for (T parameter : this.getBindableParameters()) {
 
 			if (parameter.isNamedParameter()) {
 				Assert.isTrue(nameFound || parameter.isFirst(), ALL_OR_NOTHING);
@@ -267,17 +276,14 @@ public class Parameters implements Iterable<Parameter> {
 	 * @return
 	 */
 	public static boolean isBindable(Class<?> type) {
-
 		return !TYPES.contains(type);
 	}
 
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see java.lang.Iterable#iterator()
-			 */
-	public Iterator<Parameter> iterator() {
-
+	 * (non-Javadoc)
+	 * @see java.lang.Iterable#iterator()
+	 */
+	public Iterator<T> iterator() {
 		return parameters.iterator();
 	}
-}
+}

src/main/java/org/springframework/data/repository/query/ParametersParameterAccessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2011 the original author or authors.
+ * Copyright 2008-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,7 +28,7 @@ import org.springframework.util.Assert;
  */
 public class ParametersParameterAccessor implements ParameterAccessor {
 
-	private final Parameters parameters;
+	private final Parameters<?, ?> parameters;
 	private final Object[] values;
 
 	/**
@@ -37,7 +37,7 @@ public class ParametersParameterAccessor implements ParameterAccessor {
 	 * @param parameters
 	 * @param values
 	 */
-	public ParametersParameterAccessor(Parameters parameters, Object[] values) {
+	public ParametersParameterAccessor(Parameters<?, ?> parameters, Object[] values) {
 
 		Assert.notNull(parameters);
 		Assert.notNull(values);
@@ -53,7 +53,7 @@ public class ParametersParameterAccessor implements ParameterAccessor {
 	 * 
 	 * @return the parameters will never be {@literal null}.
 	 */
-	public Parameters getParameters() {
+	public Parameters<?, ?> getParameters() {
 		return parameters;
 	}
 

src/main/java/org/springframework/data/repository/query/QueryMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2012 the original author or authors.
+ * Copyright 2008-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,7 +37,7 @@ public class QueryMethod {
 
 	private final RepositoryMetadata metadata;
 	private final Method method;
-	private final Parameters parameters;
+	private final Parameters<?, ?> parameters;
 
 	/**
 	 * Creates a new {@link QueryMethod} from the given parameters. Looks up the correct query to use for following
@@ -84,8 +84,8 @@ public class QueryMethod {
 	 * @param method
 	 * @return must not return {@literal null}.
 	 */
-	protected Parameters createParameters(Method method) {
-		return new Parameters(method);
+	protected Parameters<?, ?> createParameters(Method method) {
+		return new DefaultParameters(method);
 	}
 
 	/**
@@ -189,7 +189,7 @@ public class QueryMethod {
 	 * 
 	 * @return
 	 */
-	public Parameters getParameters() {
+	public Parameters<?, ?> getParameters() {
 		return parameters;
 	}
 

src/test/java/org/springframework/data/repository/query/ParametersParameterAccessorUnitTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,11 +32,11 @@ import org.springframework.data.domain.Pageable;
  */
 public class ParametersParameterAccessorUnitTests {
 
-	Parameters parameters;
+	Parameters<?, ?> parameters;
 
 	@Before
 	public void setUp() throws Exception {
-		parameters = new Parameters(Sample.class.getMethod("method", String.class, int.class));
+		parameters = new DefaultParameters(Sample.class.getMethod("method", String.class, int.class));
 	}
 
 	@Test
@@ -59,7 +59,7 @@ public class ParametersParameterAccessorUnitTests {
 		assertThat(accessor.hasBindableNullValue(), is(true));
 
 		Method method = Sample.class.getMethod("method", Pageable.class, String.class);
-		Parameters parameters = new Parameters(method);
+		DefaultParameters parameters = new DefaultParameters(method);
 
 		accessor = new ParametersParameterAccessor(parameters, new Object[] { null, "Foo" });
 		assertThat(accessor.hasBindableNullValue(), is(false));

src/test/java/org/springframework/data/repository/query/ParametersUnitTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2010 the original author or authors.
+ * Copyright 2008-2013 the original author or authors.
  * 
  * 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
@@ -46,28 +46,28 @@ public class ParametersUnitTests {
 		Method validWithPageable = SampleDao.class.getMethod("validWithPageable", String.class, Pageable.class);
 		Method validWithSort = SampleDao.class.getMethod("validWithSort", String.class, Sort.class);
 
-		new Parameters(valid);
-		new Parameters(validWithPageable);
-		new Parameters(validWithSort);
+		new DefaultParameters(valid);
+		new DefaultParameters(validWithPageable);
+		new DefaultParameters(validWithSort);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void rejectsInvalidMethodWithParamMissing() throws Exception {
 
 		Method method = SampleDao.class.getMethod("invalidParamMissing", String.class, String.class);
-		new Parameters(method);
+		new DefaultParameters(method);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void rejectsNullMethod() throws Exception {
 
-		new Parameters(null);
+		new DefaultParameters(null);
 	}
 
 	@Test
 	public void detectsNamedParameterCorrectly() throws Exception {
 
-		Parameters parameters = getParametersFor("validWithSort", String.class, Sort.class);
+		Parameters<?, ?> parameters = getParametersFor("validWithSort", String.class, Sort.class);
 
 		Parameter parameter = parameters.getParameter(0);
 
@@ -85,12 +85,12 @@ public class ParametersUnitTests {
 
 		Method method = SampleDao.class.getMethod("validWithSortFirst", Sort.class, String.class);
 
-		Parameters parameters = new Parameters(method);
+		Parameters<?, ?> parameters = new DefaultParameters(method);
 		assertThat(parameters.getBindableParameter(0).getIndex(), is(1));
 
 		method = SampleDao.class.getMethod("validWithSortInBetween", String.class, Sort.class, String.class);
 
-		parameters = new Parameters(method);
+		parameters = new DefaultParameters(method);
 
 		assertThat(parameters.getBindableParameter(0).getIndex(), is(0));
 		assertThat(parameters.getBindableParameter(1).getIndex(), is(2));
@@ -99,28 +99,28 @@ public class ParametersUnitTests {
 	@Test
 	public void detectsEmptyParameterListCorrectly() throws Exception {
 
-		Parameters parameters = getParametersFor("emptyParameters");
+		Parameters<?, ?> parameters = getParametersFor("emptyParameters");
 		assertThat(parameters.hasParameterAt(0), is(false));
 	}
 
 	@Test
 	public void detectsPageableParameter() throws Exception {
-		Parameters parameters = getParametersFor("validWithPageable", String.class, Pageable.class);
+		Parameters<?, ?> parameters = getParametersFor("validWithPageable", String.class, Pageable.class);
 		assertThat(parameters.getPageableIndex(), is(1));
 	}
 
 	@Test
 	public void detectsSortParameter() throws Exception {
-		Parameters parameters = getParametersFor("validWithSort", String.class, Sort.class);
+		Parameters<?, ?> parameters = getParametersFor("validWithSort", String.class, Sort.class);
 		assertThat(parameters.getSortIndex(), is(1));
 	}
 
-	private Parameters getParametersFor(String methodName, Class<?>... parameterTypes) throws SecurityException,
+	private Parameters<?, ?> getParametersFor(String methodName, Class<?>... parameterTypes) throws SecurityException,
 			NoSuchMethodException {
 
 		Method method = SampleDao.class.getMethod(methodName, parameterTypes);
 
-		return new Parameters(method);
+		return new DefaultParameters(method);
 	}
 
 	static class User {

src/test/java/org/springframework/data/repository/query/SimpleParameterAccessorUnitTests.java

@@ -1,17 +1,17 @@
 /*
- * Copyright 2008-2010 the original author or authors.
- * 
- * 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
- * 
+ * Copyright 2008-2013 the original author or authors.
+ *
+ * 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.
+ * 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 org.springframework.data.repository.query;
 
@@ -31,14 +31,14 @@ import org.springframework.data.domain.Sort;
  */
 public class SimpleParameterAccessorUnitTests {
 
-	Parameters parameters, sortParameters, pageableParameters;
+	Parameters<?, ?> parameters, sortParameters, pageableParameters;
 
 	@Before
 	public void setUp() throws SecurityException, NoSuchMethodException {
 
-		parameters = new Parameters(Sample.class.getMethod("sample", String.class));
-		sortParameters = new Parameters(Sample.class.getMethod("sample1", String.class, Sort.class));
-		pageableParameters = new Parameters(Sample.class.getMethod("sample2", String.class, Pageable.class));
+		parameters = new DefaultParameters(Sample.class.getMethod("sample", String.class));
+		sortParameters = new DefaultParameters(Sample.class.getMethod("sample1", String.class, Sort.class));
+		pageableParameters = new DefaultParameters(Sample.class.getMethod("sample2", String.class, Pageable.class));
 	}
 
 	@Test