#1072_visitor_set

javaparser-core/src/main/java/com/github/javaparser/utils/VisitorSet.java

@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
+ * Copyright (C) 2011, 2013-2016 The JavaParser Team.
+ *
+ * This file is part of JavaParser.
+ *
+ * JavaParser can be used either under the terms of
+ * a) the GNU Lesser General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * b) the terms of the Apache License
+ *
+ * You should have received a copy of both licenses in LICENCE.LGPL and
+ * LICENCE.APACHE. Please refer to those files for details.
+ *
+ * JavaParser is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ */
+
+package com.github.javaparser.utils;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import com.github.javaparser.ast.Node;
+import com.github.javaparser.ast.visitor.GenericVisitor;
+import com.github.javaparser.ast.visitor.Visitable;
+import com.github.javaparser.ast.visitor.VoidVisitor;
+
+/**
+ * A set that overrides the equals and hashcode calculation of the added nodes
+ * by using another equals and hashcode visitor for those methods.
+ */
+public class VisitorSet<N extends Node> implements Set<N> {
+
+    private final Set<EqualsHashcodeOverridingFacade> innerSet = new HashSet<>();
+    private final GenericVisitor<Integer, Void> hashcodeVisitor;
+    private final GenericVisitor<Boolean, Visitable> equalsVisitor;
+
+    /**
+     * Pass the visitors to use for equals and hashcode.
+     */
+    public VisitorSet(GenericVisitor<Integer, Void> hashcodeVisitor, GenericVisitor<Boolean, Visitable> equalsVisitor) {
+        this.hashcodeVisitor = hashcodeVisitor;
+        this.equalsVisitor = equalsVisitor;
+    }
+
+    @Override
+    public boolean add(N elem) {
+        return innerSet.add(new EqualsHashcodeOverridingFacade(elem));
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends N> col) {
+        boolean modified = false;
+        for (N elem : col)
+            if (add(elem))
+                modified = true;
+        return modified;
+    }
+
+    @Override
+    public void clear() {
+        innerSet.clear();
+    }
+
+    @Override
+    public boolean contains(Object elem) {
+        return innerSet.contains(new EqualsHashcodeOverridingFacade((N) elem));
+    }
+
+    @Override
+    public boolean containsAll(Collection<?> col) {
+        for (Object elem : col)
+            if (!contains(elem))
+                return false;
+        return true;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return innerSet.isEmpty();
+    }
+
+    @Override
+    public Iterator<N> iterator() {
+        return new Iterator<N>() {
+            final Iterator<EqualsHashcodeOverridingFacade> itr = innerSet.iterator();
+
+            @Override
+            public boolean hasNext() {
+                return itr.hasNext();
+            }
+
+            @Override
+            public N next() {
+                return itr.next().overridden;
+            }
+
+            @Override
+            public void remove() {
+                itr.remove();
+            }
+        };
+    }
+
+    @Override
+    public boolean remove(Object elem) {
+        return innerSet.remove(new EqualsHashcodeOverridingFacade((N) elem));
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> col) {
+        boolean modified = false;
+        for (Object elem : col)
+            if (remove(elem))
+                modified = true;
+        return modified;
+    }
+
+    @Override
+    public boolean retainAll(Collection<?> col) {
+        int oldSetSize = innerSet.size();
+        innerSet.clear();
+        addAll((Collection<? extends N>) col);
+        return innerSet.size() != oldSetSize;
+    }
+
+    @Override
+    public int size() {
+        return innerSet.size();
+    }
+
+    @Override
+    public Object[] toArray() {
+        return innerSet.stream().map(facade -> facade.overridden).collect(Collectors.toList()).toArray();
+    }
+
+    @Override
+    public <T> T[] toArray(T[] arr) {
+        return innerSet.stream().map(facade -> facade.overridden).collect(Collectors.toList()).toArray(arr);
+    }
+
+    private class EqualsHashcodeOverridingFacade implements Visitable {
+        private final N overridden;
+
+        EqualsHashcodeOverridingFacade(N overridden) {
+            this.overridden = overridden;
+        }
+
+        @Override
+        public <R, A> R accept(GenericVisitor<R, A> v, A arg) {
+            throw new AssertionError();
+        }
+
+        @Override
+        public <A> void accept(VoidVisitor<A> v, A arg) {
+            throw new AssertionError();
+        }
+
+        @Override
+        public final int hashCode() {
+            return overridden.accept(hashcodeVisitor, null);
+        }
+
+        @Override
+        public boolean equals(final Object obj) {
+            if (obj == null || !(obj instanceof VisitorSet.EqualsHashcodeOverridingFacade)) {
+                return false;
+            }
+            return overridden.accept(equalsVisitor, ((EqualsHashcodeOverridingFacade) obj).overridden);
+        }
+    }
+
+}

javaparser-testing/src/test/java/com/github/javaparser/utils/VisitorSetTest.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
+ * Copyright (C) 2011, 2013-2016 The JavaParser Team.
+ *
+ * This file is part of JavaParser.
+ *
+ * JavaParser can be used either under the terms of
+ * a) the GNU Lesser General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * b) the terms of the Apache License
+ *
+ * You should have received a copy of both licenses in LICENCE.LGPL and
+ * LICENCE.APACHE. Please refer to those files for details.
+ *
+ * JavaParser is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ */
+
+package com.github.javaparser.utils;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+import org.junit.Test;
+
+import com.github.javaparser.JavaParser;
+import com.github.javaparser.ast.CompilationUnit;
+import com.github.javaparser.ast.visitor.ObjectIdentityEqualsVisitor;
+import com.github.javaparser.ast.visitor.ObjectIdentityHashCodeVisitor;
+
+public class VisitorSetTest {
+
+    @Test
+    public void normalEqualsDoesDeepCompare() {
+        Set<CompilationUnit> set = new HashSet<>();
+        set.add(JavaParser.parse("class X{}"));
+        set.add(JavaParser.parse("class X{}"));
+        assertEquals(1, set.size());
+    }
+
+    @Test
+    public void objectIdentityEqualsDoesShallowCompare() {
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.add(JavaParser.parse("class X{}"));
+        set.add(JavaParser.parse("class X{}"));
+        assertEquals(2, set.size());
+    }
+
+    @Test
+    public void visitorSetContains() {
+        CompilationUnit x1 = JavaParser.parse("class X{}");
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.add(x1);
+        assertTrue(set.contains(x1));
+    }
+
+    @Test
+    public void visitorSetContainsAll() {
+        List<CompilationUnit> lst = new ArrayList<>();
+        lst.add(JavaParser.parse("class X{}"));
+        lst.add(JavaParser.parse("class X{}"));
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.addAll(lst);
+        assertTrue(set.size() == 2 && set.containsAll(lst));
+    }
+
+    @Test
+    public void visitorSetIterator() {
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.add(JavaParser.parse("class X{}"));
+        set.add(JavaParser.parse("class X{}"));
+        Iterator<CompilationUnit> itr = set.iterator();
+        itr.next();
+        itr.remove();
+        assertTrue(set.size() == 1);
+        itr.next();
+        itr.remove();
+        assertTrue(set.size() == 0);
+    }
+
+    @Test
+    public void visitorSetRemove() {
+        CompilationUnit x1 = JavaParser.parse("class X{}");
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.add(x1);
+        assertTrue(set.remove(x1));
+    }
+
+    @Test
+    public void visitorSetRemoveAll() {
+        List<CompilationUnit> lst = new ArrayList<>();
+        lst.add(JavaParser.parse("class X{}"));
+        lst.add(JavaParser.parse("class X{}"));
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.addAll(lst);
+        set.removeAll(lst);
+        assertTrue(set.size() == 0);
+    }
+
+    @Test
+    public void visitorSetRetainAll() {
+        List<CompilationUnit> lst = new ArrayList<>();
+        lst.add(JavaParser.parse("class X{}"));
+        lst.add(JavaParser.parse("class X{}"));
+        Set<CompilationUnit> set = new VisitorSet<>(new ObjectIdentityHashCodeVisitor(),
+                new ObjectIdentityEqualsVisitor());
+        set.addAll(lst);
+        set.add(JavaParser.parse("class X{}"));
+        set.retainAll(lst);
+        assertTrue(set.size() == 2);
+    }
+
+}