jinterface: match/bind added to OtpErlangObject

Adding these two methods to the OtpErlangObject abstract class makes possible
implementing of pattern matching and variable binding for all types of Erlang
terms. Particular implementations may vary and include additional classes to
define Variable placeholder objects and Bindings objects. Also Parser class
may be added to facilitate creating complex patterns and terms.

The purpose of this commit is to provide low level interface base methods
sufficient for variety of higher level pattern matching/variable binding
implementations.

OtpErlangMap class is re-designed for efficiency (it is based on HashMap now).

All changes are backward-compatible. Detailed test cases implemented.

2 files changed, 586 insertions, 1 deletions

diff --git a/lib/jinterface/test/jinterface_SUITE_data/CoreMatchBind.java b/lib/jinterface/test/jinterface_SUITE_data/CoreMatchBind.java
new file mode 100644
index 0000000000..a78a63093e
--- /dev/null
+++ b/lib/jinterface/test/jinterface_SUITE_data/CoreMatchBind.java
@@ -0,0 +1,584 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2000-2015. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+import com.ericsson.otp.erlang.OtpErlangException;
+import com.ericsson.otp.erlang.OtpErlangInt;
+import com.ericsson.otp.erlang.OtpErlangList;
+import com.ericsson.otp.erlang.OtpErlangMap;
+import com.ericsson.otp.erlang.OtpErlangObject;
+import com.ericsson.otp.erlang.OtpErlangTuple;
+import com.ericsson.otp.erlang.OtpOutputStream;
+
+public class CoreMatchBind {
+
+    @SuppressWarnings("serial")
+    private static class DumbObject extends OtpErlangObject {
+
+        @Override
+        public String toString() {
+            return this.getClass().getSimpleName();
+        }
+
+        @Override
+        public void encode(final OtpOutputStream buf) {
+            fail("unexpected encode() call");
+        }
+
+        @Override
+        public boolean equals(final Object o) {
+            fail("unexpected equals() call");
+            return false;
+        }
+
+    }
+
+    @SuppressWarnings("serial")
+    private static class BoundObject extends OtpErlangObject {
+
+        @Override
+        public String toString() {
+            return this.getClass().getSimpleName();
+        }
+
+        @Override
+        public void encode(final OtpOutputStream buf) {
+            fail("unexpected encode() call");
+        }
+
+        @Override
+        public boolean equals(final Object o) {
+            fail("unexpected equals() call");
+            return false;
+        }
+
+    }
+
+    @SuppressWarnings("serial")
+    private static class TestObject extends OtpErlangObject {
+
+        private final Binder binder;
+        private DumbObject dumb;
+        private boolean flag;
+        private BoundObject obj;
+
+        public TestObject(final boolean flag, final Binder binder,
+                final DumbObject dumb) {
+            this.flag = flag;
+            this.binder = binder;
+            this.dumb = dumb;
+        }
+
+        public TestObject(final Binder binder, final BoundObject obj) {
+            this.binder = binder;
+            this.obj = obj;
+        }
+
+        public DumbObject getDumb() {
+            return dumb;
+        }
+
+        @Override
+        public String toString() {
+            return flag ? "T" : "F";
+        }
+
+        @Override
+        public void encode(final OtpOutputStream buf) {
+            fail("unexpected encode() call");
+        }
+
+        @Override
+        public boolean equals(final Object o) {
+            if (obj == null) {
+                fail("unexpected equals() call");
+            }
+            return o == obj;
+        }
+
+        @Override
+        public <T> boolean match(final OtpErlangObject term, final T binds) {
+            if (binds != binder) {
+                fail("invalid binder");
+            }
+            if (term != dumb) {
+                fail("invalid object");
+            }
+            return flag;
+        }
+
+        @Override
+        public <T> OtpErlangObject bind(final T binds)
+                throws OtpErlangException {
+            if (binds != binder) {
+                fail("invalid binder");
+            }
+            return obj;
+        }
+
+    }
+
+    /*
+     * "always matched" object
+     */
+    @SuppressWarnings("serial")
+    private static class Any extends OtpErlangObject {
+
+        @Override
+        public String toString() {
+            return "any";
+        }
+
+        @Override
+        public void encode(final OtpOutputStream buf) {
+            fail("unexpected encode() call");
+        }
+
+        @Override
+        public boolean equals(final Object o) {
+            fail("unexpected equals() call");
+            return false;
+        }
+
+        @Override
+        public <T> boolean match(final OtpErlangObject term, final T binds) {
+            return true;
+        }
+    }
+
+    private static class Binder {
+        // make object pair for match() testing
+        TestObject makeTest(final boolean flag) {
+            return new TestObject(flag, this, new DumbObject());
+        }
+
+        // make object pair for bind() testing
+        TestObject makeTest() {
+            return new TestObject(this, new BoundObject());
+        }
+    }
+
+    private static void isNotNull(final Object o) throws Exception {
+        if (o == null) {
+            throw new Exception("not null expected");
+        }
+    }
+
+    private static void fail(final String string) {
+        System.err.println(string);
+        new Throwable().printStackTrace(System.err);
+        System.exit(1);
+    }
+
+    private static void isT(final boolean b) throws Exception {
+        if (!b) {
+            throw new Exception("true expected");
+        }
+    }
+
+    private static void isF(final boolean b) throws Exception {
+        if (b) {
+            throw new Exception("false expected");
+        }
+    }
+
+    private static void equals(final OtpErlangObject a, final OtpErlangObject b)
+            throws Exception {
+        if (!a.equals(b)) {
+            throw new Exception(a + " != " + b);
+        }
+    }
+
+    /*
+     * scalar match test - match particular test object (producing given result)
+     * against particular dumb object passing particular bindings object; ensure
+     * all participants are used as expected in match behavior, check result.
+     */
+    private static void scalar_match_test() throws Exception {
+        final Binder bind = new Binder();
+
+        final TestObject t = bind.makeTest(true);
+        isT(t.match(t.getDumb(), bind));
+
+        final TestObject f = bind.makeTest(false);
+        isF(f.match(f.getDumb(), bind));
+    }
+
+    /*
+     * scalar bind test - ensure right object generated based on bindings
+     */
+    private static void scalar_bind_test() throws Exception {
+        final Binder bind = new Binder();
+        final TestObject t = bind.makeTest();
+        final OtpErlangObject o = t.bind(bind);
+        isNotNull(o);
+        equals(t, o);
+    }
+
+    /*
+     * used by tuple_arity_match_test()
+     */
+    private static OtpErlangObject mkTuplePattern(final int n) {
+        final Any a[] = new Any[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = new Any();
+        }
+        return new OtpErlangTuple(a);
+    }
+
+    /*
+     * used by tuple_arity_match_test()
+     */
+    private static OtpErlangObject mkTupleObject(final int n) {
+        final DumbObject a[] = new DumbObject[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = new DumbObject();
+        }
+        return new OtpErlangTuple(a);
+    }
+
+    /*
+     * ensure only tuples of the same arity can match
+     */
+    private static void tuple_arity_match_test(final int m, final int n)
+            throws Exception {
+        final Binder bind = new Binder();
+        for (int i = m; i < n; i++) {
+            for (int j = m; j < n; j++) {
+                final OtpErlangObject p = mkTuplePattern(i);
+                final OtpErlangObject o = mkTupleObject(j);
+                if (i == j) {
+                    isT(p.match(o, bind));
+                } else {
+                    isF(p.match(o, bind));
+                }
+            }
+        }
+    }
+
+    /*
+     * tuple match test - ensure elements of tuple are matched to corresponding
+     * elements of tested object and result is logical "and" over all elements.
+     */
+    private static void tuple_match_test(final int n) throws Exception {
+        final Binder bind = new Binder();
+        final int max = 1 << n;
+        final TestObject a[] = new TestObject[n];
+        final DumbObject d[] = new DumbObject[n];
+        for (int k = 0; k < max; k++) {
+            for (int m = 1, i = 0; m < max; m = m << 1, i++) {
+                d[i] = new DumbObject();
+                a[i] = new TestObject((k & m) != 0, bind, d[i]);
+            }
+            final OtpErlangObject tpl = new OtpErlangTuple(a);
+            final OtpErlangObject obj = new OtpErlangTuple(d);
+            if (k + 1 < max) {
+                isF(tpl.match(obj, bind));
+            } else {
+                isT(tpl.match(obj, bind));
+            }
+        }
+    }
+
+    /*
+     * tuple bind test - ensure result is a tuple where each element is a result
+     * of binding of corresponding pattern element using provided bindings.
+     */
+    private static void tuple_bind_test(final int n) throws Exception {
+        final Binder bind = new Binder();
+        final TestObject a[] = new TestObject[n];
+        final OtpErlangObject b[] = new OtpErlangObject[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = bind.makeTest();
+            b[i] = a[i].obj;
+        }
+        final OtpErlangObject t = new OtpErlangTuple(a);
+        final OtpErlangObject o = t.bind(bind);
+        isNotNull(o);
+        equals(t, o);
+    }
+
+    private static OtpErlangObject mkListPattern(final int n, final boolean tail)
+            throws OtpErlangException {
+        final Any a[] = new Any[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = new Any();
+        }
+        return tail ? new OtpErlangList(a, new Any()) : new OtpErlangList(a);
+    }
+
+    private static OtpErlangObject mkListObject(final int n, final boolean tail)
+            throws OtpErlangException {
+        final DumbObject a[] = new DumbObject[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = new DumbObject();
+        }
+        return tail ? new OtpErlangList(a, new DumbObject())
+                : new OtpErlangList(a);
+    }
+
+    /*
+     * ensure only lists of the same arity and same tail presence can match
+     */
+    private static void list_arity_match_test(final int m, final int n)
+            throws Exception {
+        final Binder bind = new Binder();
+        for (int i = m; i < n; i++) {
+            for (int j = m; j < n; j++) {
+                for (int k = 0; k < 2; k++) {
+                    if (i == 0 && k == 1) {
+                        continue;
+                    }
+                    for (int l = 0; l < 2; l++) {
+                        if (j == 0 && l == 1) {
+                            continue;
+                        }
+                        final OtpErlangObject p = mkListPattern(i, k == 1);
+                        final OtpErlangObject o = mkListObject(j, l == 1);
+                        if (i == j && k == l || k == 1 && i <= j) {
+                            isT(p.match(o, bind));
+                        } else {
+                            isF(p.match(o, bind));
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /*
+     * lists match test - ensure elements of lists are matched to corresponding
+     * elements of tested object and result is logical "and" over all elements,
+     * count tails as well
+     */
+    private static void list_match_test(final int n) throws Exception {
+        final Binder bind = new Binder();
+        final int max = 1 << n;
+        final TestObject a[] = new TestObject[n];
+        final DumbObject d[] = new DumbObject[n];
+        final DumbObject e[] = new DumbObject[n + 1];
+        for (int k = 0; k < max; k++) {
+            for (int m = 1, i = 0; m < max; m = m << 1, i++) {
+                d[i] = new DumbObject();
+                e[i] = d[i];
+                a[i] = new TestObject((k & m) != 0, bind, d[i]);
+            }
+            for (int i = n; i < n + 1; i++) {
+                e[i] = new DumbObject();
+            }
+            final OtpErlangObject lst = new OtpErlangList(a);
+            final OtpErlangObject obj = new OtpErlangList(d);
+            final OtpErlangObject ext = new OtpErlangList(e);
+            final OtpErlangObject eTl = new OtpErlangList(e, new DumbObject());
+
+            if (n > 0) {
+                final DumbObject dTail = new DumbObject();
+                final TestObject tTail = new TestObject(true, bind, dTail);
+                final TestObject fTail = new TestObject(false, bind, dTail);
+                final OtpErlangObject fTailLst = new OtpErlangList(a, fTail);
+                final OtpErlangObject tTailLst = new OtpErlangList(a, tTail);
+                final OtpErlangObject tailObj = new OtpErlangList(d, dTail);
+
+                // match lists with non-matching tails is always false
+                isF(fTailLst.match(tailObj, bind));
+
+                // match list with no tail to list with tail is always false
+                isF(lst.match(tailObj, bind));
+
+                // matching lists with matching tails
+                if (k + 1 < max) {
+                    isF(tTailLst.match(tailObj, bind));
+                } else {
+                    isT(tTailLst.match(tailObj, bind));
+                }
+
+                // matching shorter pattern with last tail to longer list
+                // with or with no extra tail; matching list pattern
+                // with last tail to same length list with no tail.
+                final Any aTail = new Any();
+                final OtpErlangObject shortLst = new OtpErlangList(a, aTail);
+                if (k + 1 < max) {
+                    isF(shortLst.match(obj, bind)); // same arity
+                    isF(shortLst.match(ext, bind)); // pattern arity is less
+                    isF(shortLst.match(eTl, bind)); //
+                } else {
+                    isT(shortLst.match(obj, bind)); // same arity
+                    isT(shortLst.match(ext, bind)); // pattern arity is less
+                    isT(shortLst.match(eTl, bind)); //
+                }
+            }
+
+            // matching lists with no tails
+            if (k + 1 < max) {
+                isF(lst.match(obj, bind));
+            } else {
+                isT(lst.match(obj, bind));
+            }
+
+            // extra-length object, no tail in "pattern"
+            isF(lst.match(ext, bind));
+        }
+    }
+
+    /*
+     * list bind test - ensure result is a list where each element is a result
+     * of binding of corresponding pattern element using provided bindings.
+     */
+    private static void list_bind_test(final int n) throws Exception {
+        final Binder bind = new Binder();
+        final TestObject a[] = new TestObject[n];
+        final OtpErlangObject b[] = new OtpErlangObject[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = bind.makeTest();
+            b[i] = a[i].obj;
+        }
+        OtpErlangObject t = new OtpErlangList(a);
+        OtpErlangObject o = t.bind(bind);
+        isNotNull(o);
+        equals(t, o);
+        if (n > 0) {
+            // improper list case
+            t = new OtpErlangList(a, bind.makeTest());
+            o = t.bind(bind);
+            isNotNull(o);
+            equals(t, o);
+        }
+    }
+
+    /*
+     * map match test - object may have more keys than pattern
+     */
+    private static void map_match_test(final int m, final int n)
+            throws Exception {
+        final Binder bind = new Binder();
+
+        // pattern side - m elements
+        final OtpErlangObject k1[] = new OtpErlangObject[m];
+        final TestObject a[] = new TestObject[m];
+
+        // object side - n elements
+        final OtpErlangObject k2[] = new OtpErlangObject[n];
+        final DumbObject d[] = new DumbObject[n];
+
+        final int max = Math.max(m, n);
+        final int mskHi = 1 << max;
+        final int full = (1 << m) - 1;
+        for (int k = 0; k < mskHi; k++) {
+            for (int msk = 1, i = 0; msk < mskHi; msk = msk << 1, i++) {
+                if (i < n) {
+                    k2[i] = new OtpErlangInt(i);
+                    d[i] = new DumbObject();
+                }
+                if (i < m) {
+                    k1[i] = new OtpErlangInt(i);
+                    a[i] = new TestObject((k & msk) != 0, bind, i < n ? d[i]
+                            : new DumbObject());
+                }
+            }
+            final OtpErlangObject map = new OtpErlangMap(k1, a); // m items
+            final OtpErlangObject obj = new OtpErlangMap(k2, d); // n items
+            if ((k & full) == full && m <= n) {
+                isT(map.match(obj, bind));
+            } else {
+                isF(map.match(obj, bind));
+            }
+        }
+    }
+
+    /*
+     * map bind test - ensure result is a map where each element is a result of
+     * binding of corresponding pattern element using provided bindings.
+     */
+    private static void map_bind_test(final int n) throws Exception {
+        final Binder bind = new Binder();
+        final TestObject a[] = new TestObject[n];
+        final OtpErlangObject b[] = new OtpErlangObject[n];
+        final OtpErlangObject k[] = new OtpErlangObject[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = bind.makeTest();
+            b[i] = a[i].obj;
+            k[i] = new OtpErlangInt(i);
+        }
+        final OtpErlangObject t = new OtpErlangMap(k, a);
+        final OtpErlangObject o = t.bind(bind);
+        isNotNull(o);
+        equals(t, o);
+    }
+
+    public static void main(final String[] args) {
+        try {
+            scalar_match_test();
+            System.out.println("scalar_match_test() passed");
+
+            scalar_bind_test();
+            System.out.println("scalar_bind_test() passed");
+
+            for (int m = 0; m < 16; m++) {
+                for (int n = 0; n < 16; n++) {
+                    tuple_arity_match_test(m, n);
+                }
+            }
+            System.out.println("tuple_arity_match_test() passed");
+
+            for (int n = 0; n < 16; n++) {
+                tuple_match_test(n);
+            }
+            System.out.println("tuple_match_test() passed");
+
+            for (int n = 0; n < 16; n++) {
+                tuple_bind_test(n);
+            }
+            System.out.println("tuple_bind_test() passed");
+
+            for (int m = 0; m < 16; m++) {
+                for (int n = 0; n < 16; n++) {
+                    list_arity_match_test(m, n);
+                }
+            }
+            System.out.println("list_arity_match_test() passed");
+
+            for (int n = 0; n < 16; n++) {
+                list_match_test(n);
+            }
+            System.out.println("list_match_test() passed");
+
+            for (int n = 0; n < 16; n++) {
+                list_bind_test(n);
+            }
+            System.out.println("list_bind_test() passed");
+
+            for (int m = 0; m < 12; m++) {
+                for (int n = 0; n < 12; n++) {
+                    map_match_test(m, n);
+                }
+            }
+            System.out.println("map_match_test() passed");
+
+            for (int n = 0; n < 16; n++) {
+                map_bind_test(n);
+            }
+            System.out.println("map_bind_test() passed");
+
+        } catch (final Exception e) {
+            e.printStackTrace();
+            System.exit(1);
+        }
+
+        System.out.println("ok");
+    }
+}
diff --git a/lib/jinterface/test/jinterface_SUITE_data/Makefile.src b/lib/jinterface/test/jinterface_SUITE_data/Makefile.src
index cd68f1ead5..fe4b98a0e4 100644
--- a/lib/jinterface/test/jinterface_SUITE_data/Makefile.src
+++ b/lib/jinterface/test/jinterface_SUITE_data/Makefile.src
@@ -48,7 +48,8 @@ JAVA_FILES = \
 	MboxLinkUnlink.java \
 	NodeStatusHandler.java \
 	Maps.java \
-	FunEquals.java
+	FunEquals.java \
+	CoreMatchBind.java
 
 CLASS_FILES = $(JAVA_FILES:.java=.class)