v0.5.6 -- withDelegate added to Closure

README.md

@@ -310,4 +310,20 @@ However, the standard deviation shows that they are very different sequences of
     // prints: "AverageStats( mean:50.5, median:50.5, variance:2450.25, stdDev:49.5 )"
     println a.average()
     // prints: "AverageStats( mean:50.5, median:50.5, variance:833.25, stdDev:28.86607004772212 )"
-    println b.average()
+    println b.average()
+
+## Closure.`withDelegate`
+
+Allows setting the `delegate` of a `Closure` in-line:
+
+    static <T> Closure<T> withDelegate( Closure<T> self, Object delegate )
+    static <T> Closure<T> withDelegate( Closure<T> self, Object delegate, int strategy )
+
+So you can do:
+
+    def testClosure = { num ->
+        num + val
+    }
+
+    def value = testClosure.withDelegate( [ val: 4 ] )( 3 )
+    assert value == 7

build.gradle

@@ -6,7 +6,7 @@ apply plugin: 'signing'
 sourceCompatibility=1.6
 targetCompatibility=1.6
 
-version = '0.5.5'
+version = '0.5.6'
 
 repositories {
   mavenCentral()

src/main/groovy/com/bloidonia/groovy/extensions/ClosureExtensionMethods.groovy

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2013 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 com.bloidonia.groovy.extensions
+
+/**
+ * @author Tim Yates
+ */
+class ClosureExtensionMethods {
+
+    /**
+     * Set a Closure's delegate
+     * <pre class="groovyTestCase">
+     *   def testClosure = { num ->
+     *       num + val
+     *   }
+     *
+     *   def value = testClosure.withDelegate( [ val: 4 ] )( 3 )
+     *   assert value == 7
+     * </pre>
+     *
+     * @param self     the Closure
+     * @param delegate the object to delegate to
+     * @return         the closure but with its delegate set
+     */
+    static <T> Closure<T> withDelegate( Closure<T> self, Object delegate ) {
+        self.delegate = delegate
+        self
+    }
+
+    /**
+     * Set a Closure's delegate and resolveStrategy
+     * @param self     the Closure
+     * @param delegate the object to delegate to
+     * @param strategy the resolveStrategy to use
+     * @return         the closure but with its delegate and strategy set
+     */
+    static <T> Closure<T> withDelegate( Closure<T> self, Object delegate, int strategy ) {
+        self.delegate = delegate
+        self.resolveStrategy = strategy
+        self
+    }
+}

src/test/groovy/tests/ClosureTests.groovy

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2012-2013 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 tests
+
+import spock.lang.Specification
+
+public class ClosureTests extends Specification {
+
+    def val = 99
+
+    def testClosure = { num ->
+        num + val + val2
+    }
+
+    def 'quick test'() {
+        given:
+            def val = testClosure.withDelegate( [ val: 4, val2: 8 ] )( 3 )
+        expect:
+            // Should use val from the class, but val2 from the delegate
+            val == 110
+    }
+
+    def 'strategy test'() {
+        given:
+            def val = testClosure.withDelegate( [ val: 4, val2: 8 ], Closure.DELEGATE_FIRST )( 3 )
+        expect:
+            // val and val2 from the delegate
+            val == 15
+    }
+}