#1 Expr proto

src/main/java/org/polystat/far/Expr.java

@@ -0,0 +1,156 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020-2021 Polystat.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.polystat.far;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Boolean Expression Solver.
+ *
+ * @since 1.0
+ * @checkstyle ClassDataAbstractionCouplingCheck (500 lines)
+ */
+public final class Expr {
+
+    /**
+     * The expression.
+     */
+    private final String expr;
+
+    /**
+     * Already defined taus.
+     */
+    private final Map<String, String> already;
+
+    /**
+     * Ctor.
+     * @param bexpr Boolean expression
+     */
+    public Expr(final String bexpr) {
+        this(new HashMap<>(0), bexpr);
+    }
+
+    /**
+     * Ctor.
+     * @param map Already defined values
+     * @param bexpr Boolean expression
+     */
+    public Expr(final Map<String, String> map, final String bexpr) {
+        this.already = Collections.unmodifiableMap(map);
+        this.expr = bexpr;
+    }
+
+    /**
+     * Is it possible?
+     * @return TRUE if yes
+     */
+    public String find() {
+        final String[] ands = this.expr.split(" and ", 2);
+        final String[] ors = ands[0].substring(1, ands[0].length() - 1)
+            .split(" or ");
+        final Collection<Map<String, String>> parts =
+            new ArrayList<>(ors.length);
+        for (final String item : ors) {
+            final String[] taus = item.substring(1, item.length() - 1)
+                .split(" & ");
+            final Map<String, String> opts = new HashMap<>(taus.length);
+            for (final String tau : taus) {
+                final String[] eqs = tau.split("=");
+                opts.put(eqs[0], eqs[1]);
+            }
+            parts.add(opts);
+        }
+        String result = "";
+        for (final Map<String, String> map : parts) {
+            if (!this.matches(map)) {
+                continue;
+            }
+            final Map<String, String> join = this.merge(map);
+            final String out = Expr.print(join);
+            if (ands.length == 1) {
+                result = out;
+                break;
+            }
+            final String kid = new Expr(join, ands[1]).find();
+            if (!kid.isEmpty()) {
+                result = String.format("%s > %s", out, kid);
+                break;
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Print the map to string.
+     * @param map The map
+     * @return String
+     */
+    private static String print(final Map<String, String> map) {
+        final StringBuilder out = new StringBuilder();
+        for (final Map.Entry<String, String> ent : map.entrySet()) {
+            out.append(ent.getKey())
+                .append('=')
+                .append(ent.getValue())
+                .append(' ');
+        }
+        return out.toString().trim();
+    }
+
+    /**
+     * This map matches the already defined values.
+     * @param map The map
+     * @return TRUE if matches
+     */
+    private boolean matches(final Map<String, String> map) {
+        boolean matches = true;
+        for (final Map.Entry<String, String> ent : this.already.entrySet()) {
+            if (map.containsKey(ent.getKey()) &&
+                map.get(ent.getKey()) != ent.getValue()) {
+                matches = false;
+                break;
+            }
+        }
+        return matches;
+    }
+
+    /**
+     * Merge existing map with this one.
+     * @param map Appendix
+     * @return New map
+     */
+    private Map<String, String> merge(final Map<String, String> map) {
+        final Map<String, String> after = new HashMap<>(
+            this.already.size() + map.size()
+        );
+        after.putAll(this.already);
+        after.putAll(map);
+        return after;
+    }
+
+}

src/main/resources/org/polystat/far/opts-to-boolean-expressions.xsl

@@ -46,7 +46,7 @@ SOFTWARE.
               <xsl:text>(</xsl:text>
               <xsl:for-each select="tau">
                 <xsl:if test="position() &gt; 1">
-                  <xsl:text> and </xsl:text>
+                  <xsl:text> &amp; </xsl:text>
                 </xsl:if>
                 <xsl:text>&#x1D70F;</xsl:text>
                 <xsl:variable name="parts" select="tokenize(@i, ':')"/>

src/test/java/org/polystat/far/ExprTest.java

@@ -0,0 +1,59 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020-2021 Polystat.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.polystat.far;
+
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for {@link Expr}.
+ *
+ * @since 0.1
+ */
+public final class ExprTest {
+
+    @Test
+    public void solvesSimpleExpression() {
+        final Expr expr = new Expr(
+            "((a=1 & b=2) or (b=3)) and ((a=1) or (b=2))"
+        );
+        MatcherAssert.assertThat(
+            expr.find(),
+            Matchers.equalTo("b=3 > a=1 b=3")
+        );
+    }
+
+    @Test
+    public void failsSimpleExpression() {
+        final Expr expr = new Expr(
+            "((a=1 & b=2) or (d=4)) and ((d=5 & a=7) or (b=6 & d=1))"
+        );
+        MatcherAssert.assertThat(
+            expr.find(),
+            Matchers.equalTo("")
+        );
+    }
+
+}