Adding Builder interface, and refactoring the builder classes and BasicThreadFactory to implement this interface. Patch from Michael Wooten in LANG-601

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@925674 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/lang3/builder/Builder.java

@@ -0,0 +1,89 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.commons.lang3.builder;
+
+/**
+ * <p>
+ * The Builder interface is designed to designate a class as a <em>builder</em> 
+ * object in the Builder design pattern. Builders are capable of creating and 
+ * configuring objects or results that normally take multiple steps to construct 
+ * or are very complex to derive. 
+ * </p>
+ * 
+ * <p>
+ * The builder interface defines a single method, {@link #build()}, that 
+ * classes must implement. The result of this method should be the final 
+ * configured object or result after all building operations are performed.
+ * </p>
+ * 
+ * <p>
+ * It is a recommended practice that the methods supplied to configure the 
+ * object or result being built return a reference to <code>this</code> so that
+ * method calls can be chained together.
+ * </p>
+ * 
+ * <p>
+ * Example Builder:
+ * <code><pre>
+ * class FontBuilder implements Builder&lt;Font&gt; {
+ *     private Font font;
+ *     
+ *     public FontBuilder(String fontName) {
+ *         this.font = new Font(fontName, Font.PLAIN, 12);
+ *     }
+ * 
+ *     public FontBuilder bold() {
+ *         this.font = this.font.deriveFont(Font.BOLD);
+ *         return this; // Reference returned so calls can be chained
+ *     }
+ *     
+ *     public FontBuilder size(float pointSize) {
+ *         this.font = this.font.deriveFont(pointSize);
+ *         return this; // Reference returned so calls can be chained
+ *     }
+ * 
+ *     // Other Font construction methods
+ * 
+ *     public Font build() {
+ *         return this.font;
+ *     }
+ * }
+ * </pre></code>
+ * 
+ * Example Builder Usage:
+ * <code><pre>
+ * Font bold14ptSansSerifFont = new FontBuilder(Font.SANS_SERIF).bold()
+ *                                                              .size(14.0f)
+ *                                                              .build();
+ * </pre></code>
+ * </p>
+ * 
+ * @param <T> the type of object that the builder will construct or compute.
+ * 
+ * @author <a href="mailto:mwooten.dev@gmail.com">Michael Wooten</a>
+ * @since 3.0
+ */
+public interface Builder<T> {
+
+    /**
+     * Returns a reference to the object being constructed or result being 
+     * calculated by the builder.
+     * 
+     * @return the object constructed or result calculated by the builder.
+     */
+    public T build();
+}

src/main/java/org/apache/commons/lang3/builder/CompareToBuilder.java

@@ -89,7 +89,7 @@ import org.apache.commons.lang3.ArrayUtils;
  * @since 1.0
  * @version $Id$
  */
-public class CompareToBuilder {
+public class CompareToBuilder implements Builder<Integer> {
     
     /**
      * Current state of the comparison as appended fields are checked.
@@ -1043,5 +1043,18 @@ public class CompareToBuilder {
         return comparison;
     }
 
+    /**
+     * Returns a negative integer, a positive integer, or zero as
+     * the <code>builder</code> has judged the "left-hand" side
+     * as less than, greater than, or equal to the "right-hand"
+     * side.
+     * 
+     * @return final comparison result
+     * 
+     * @since 3.0
+     */
+    public Integer build() {
+        return toComparison();
+    }
 }
 

src/main/java/org/apache/commons/lang3/builder/EqualsBuilder.java

@@ -86,7 +86,7 @@ import org.apache.commons.lang3.Pair;
  * @since 1.0
  * @version $Id$
  */
-public class EqualsBuilder {
+public class EqualsBuilder implements Builder<Boolean> {
     
     /**
      * <p>
@@ -968,6 +968,19 @@ public class EqualsBuilder {
     public boolean isEquals() {
         return this.isEquals;
     }
+    
+    /**
+     * <p>Returns <code>true</code> if the fields that have been checked
+     * are all equal.</p>
+     *
+     * @return <code>true</code> if all of the fields that have been checked
+     *         are equal, <code>false</code> otherwise.
+     *         
+     * @since 3.0
+     */
+    public Boolean build() {
+        return isEquals();
+    }
 
     /**
      * Sets the <code>isEquals</code> value.

src/main/java/org/apache/commons/lang3/builder/HashCodeBuilder.java

@@ -93,7 +93,7 @@ import org.apache.commons.lang3.ArrayUtils;
  * @since 1.0
  * @version $Id$
  */
-public class HashCodeBuilder {
+public class HashCodeBuilder implements Builder<Integer> {
     /**
      * <p>
      * A registry of objects used by reflection methods to detect cyclical object references and avoid infinite loops.
@@ -976,6 +976,17 @@ public class HashCodeBuilder {
     public int toHashCode() {
         return iTotal;
     }
+    
+    /**
+     * Returns the computed <code>hashCode</code>.
+     * 
+     * @return <code>hashCode</code> based on the fields appended
+     * 
+     * @since 3.0
+     */
+    public Integer build() {
+        return toHashCode();
+    }
 
     /**
      * <p>

src/main/java/org/apache/commons/lang3/builder/ToStringBuilder.java

@@ -89,7 +89,7 @@ import org.apache.commons.lang3.ObjectUtils;
  * @since 1.0
  * @version $Id$
  */
-public class ToStringBuilder {
+public class ToStringBuilder implements Builder<String> {
 
     /**
      * The default style of output to use, not null.
@@ -1065,4 +1065,17 @@ public class ToStringBuilder {
         return this.getStringBuffer().toString();
     }
 
+    /**
+     * Returns the String that was build as an object representation. The 
+     * default implementation utilizes the {@link #toString()} implementation.
+     * 
+     * @return the String <code>toString</code>
+     * 
+     * @see #toString()
+     * 
+     * @since 3.0
+     */
+    public String build() {
+        return toString();
+    }
 }

src/main/java/org/apache/commons/lang3/concurrent/BasicThreadFactory.java

@@ -250,7 +250,9 @@ public class BasicThreadFactory implements ThreadFactory {
      *
      * @version $Id: $
      */
-    public static class Builder {
+    public static class Builder 
+        implements org.apache.commons.lang3.builder.Builder<BasicThreadFactory> {
+        
         /** The wrapped factory. */
         private ThreadFactory wrappedFactory;
 

src/test/java/org/apache/commons/lang3/builder/CompareToBuilderTest.java

@@ -272,6 +272,20 @@ public class CompareToBuilderTest extends TestCase {
         assertTrue(new CompareToBuilder().append((Object) null, (Object) null).toComparison() == 0);
         assertTrue(new CompareToBuilder().append(null, o1).toComparison() < 0);
     }
+    
+    public void testObjectBuild() {
+        TestObject o1 = new TestObject(4);
+        TestObject o2 = new TestObject(4);
+        assertTrue(new CompareToBuilder().append(o1, o1).build() == 0);
+        assertTrue(new CompareToBuilder().append(o1, o2).build() == 0);
+        o2.setA(5);
+        assertTrue(new CompareToBuilder().append(o1, o2).build() < 0);
+        assertTrue(new CompareToBuilder().append(o2, o1).build() > 0);
+        
+        assertTrue(new CompareToBuilder().append(o1, null).build() > 0);
+        assertTrue(new CompareToBuilder().append((Object) null, (Object) null).build() == 0);
+        assertTrue(new CompareToBuilder().append(null, o1).build() < 0);
+    }
 
     public void testObjectEx2() {
         TestObject o1 = new TestObject(4);

src/test/java/org/apache/commons/lang3/builder/EqualsBuilderTest.java

@@ -305,6 +305,21 @@ public class EqualsBuilderTest extends TestCase {
         assertTrue(!new EqualsBuilder().append(null, o2).isEquals());
         assertTrue(new EqualsBuilder().append((Object) null, (Object) null).isEquals());
     }
+    
+    public void testObjectBuild() {
+        TestObject o1 = new TestObject(4);
+        TestObject o2 = new TestObject(5);
+        assertTrue(new EqualsBuilder().append(o1, o1).build());
+        assertTrue(!new EqualsBuilder().append(o1, o2).build());
+        o2.setA(4);
+        assertTrue(new EqualsBuilder().append(o1, o2).build());
+
+        assertTrue(!new EqualsBuilder().append(o1, this).build());
+        
+        assertTrue(!new EqualsBuilder().append(o1, null).build());
+        assertTrue(!new EqualsBuilder().append(null, o2).build());
+        assertTrue(new EqualsBuilder().append((Object) null, (Object) null).build());
+    }
 
     public void testLong() {
         long o1 = 1L;

src/test/java/org/apache/commons/lang3/builder/HashCodeBuilderTest.java

@@ -205,6 +205,13 @@ public class HashCodeBuilderTest extends TestCase {
         obj = new Object();
         assertEquals(17 * 37 + obj.hashCode(), new HashCodeBuilder(17, 37).append(obj).toHashCode());
     }
+    
+    public void testObjectBuild() {
+        Object obj = null;
+        assertEquals(17 * 37, new HashCodeBuilder(17, 37).append(obj).build().intValue());
+        obj = new Object();
+        assertEquals(17 * 37 + obj.hashCode(), new HashCodeBuilder(17, 37).append(obj).build().intValue());
+    }
 
     @SuppressWarnings("cast") // cast is not really needed, keep for consistency
     public void testLong() {

src/test/java/org/apache/commons/lang3/builder/ToStringBuilderTest.java

@@ -619,6 +619,23 @@ public class ToStringBuilderTest extends TestCase {
         assertEquals(baseStr + "[a=<size=0>]", new ToStringBuilder(base).append("a", (Object) new String[0], false).toString());
         assertEquals(baseStr + "[a={}]", new ToStringBuilder(base).append("a", (Object) new String[0], true).toString());
     }
+    
+    public void testObjectBuild() {
+        Integer i3 = new Integer(3);
+        Integer i4 = new Integer(4);
+        assertEquals(baseStr + "[<null>]", new ToStringBuilder(base).append((Object) null).build());
+        assertEquals(baseStr + "[3]", new ToStringBuilder(base).append(i3).build());
+        assertEquals(baseStr + "[a=<null>]", new ToStringBuilder(base).append("a", (Object) null).build());
+        assertEquals(baseStr + "[a=3]", new ToStringBuilder(base).append("a", i3).build());
+        assertEquals(baseStr + "[a=3,b=4]", new ToStringBuilder(base).append("a", i3).append("b", i4).build());
+        assertEquals(baseStr + "[a=<Integer>]", new ToStringBuilder(base).append("a", i3, false).build());
+        assertEquals(baseStr + "[a=<size=0>]", new ToStringBuilder(base).append("a", new ArrayList<Object>(), false).build());
+        assertEquals(baseStr + "[a=[]]", new ToStringBuilder(base).append("a", new ArrayList<Object>(), true).build());
+        assertEquals(baseStr + "[a=<size=0>]", new ToStringBuilder(base).append("a", new HashMap<Object, Object>(), false).build());
+        assertEquals(baseStr + "[a={}]", new ToStringBuilder(base).append("a", new HashMap<Object, Object>(), true).build());
+        assertEquals(baseStr + "[a=<size=0>]", new ToStringBuilder(base).append("a", (Object) new String[0], false).build());
+        assertEquals(baseStr + "[a={}]", new ToStringBuilder(base).append("a", (Object) new String[0], true).build());
+    }
 
     public void testLong() {
         assertEquals(baseStr + "[3]", new ToStringBuilder(base).append(3L).toString());