Populate model/ hierarchy

[yangtools.git] / model / yang-model-api / src / main / java / org / opendaylight / yangtools / yang / model / api / stmt / PatternExpression.java

diff --git a/model/yang-model-api/src/main/java/org/opendaylight/yangtools/yang/model/api/stmt/PatternExpression.java b/model/yang-model-api/src/main/java/org/opendaylight/yangtools/yang/model/api/stmt/PatternExpression.java
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+/*
+ * Copyright (c) 2020 PANTHEON.tech, s.r.o. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.yangtools.yang.model.api.stmt;
+
+import static java.util.Objects.requireNonNull;
+
+import com.google.common.annotations.Beta;
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+import org.opendaylight.yangtools.concepts.Immutable;
+
+/**
+ * An intermediate capture of the argument to {@code pattern} statement. It exposes both XSD regular expression, as well
+ * as a {@link java.util.regex.Pattern} pattern.
+ */
+@Beta
+@NonNullByDefault
+public final class PatternExpression implements Immutable {
+    private final String pattern;
+    private final String regex;
+
+    private PatternExpression(final String regex, final String pattern) {
+        this.regex = requireNonNull(regex);
+        this.pattern = requireNonNull(pattern);
+    }
+
+    public static PatternExpression of(final String regex, final String pattern) {
+        return new PatternExpression(regex, pattern);
+    }
+
+    /**
+     * Returns a Java {@link java.util.regex.Pattern}-compatible regular expression (pattern). Returned string performs
+     * equivalent  matching in terms of enforcement, but it may have a structure completely different from the one in
+     * YANG model.
+     *
+     * @return string Java Pattern regular expression
+     */
+    // FIXME: should we be providing a Pattern instance? This, along with the other method is treading the fine
+    //        balance between usability of the effective model, the purity of effective view model and memory
+    //        overhead. We pick usability and memory footprint and expose both methods from effective model.
+    public String getJavaPatternString() {
+        return pattern;
+    }
+
+    /**
+     * Returns a raw regular expression as it was declared in a source. This string conforms to XSD regular expression
+     * syntax, which is notably different from Java's Pattern string.
+     *
+     * @return argument of pattern statement as it was declared in YANG model.
+     */
+    public String getRegularExpressionString() {
+        return regex;
+    }
+
+    @Override
+    public int hashCode() {
+        return regex.hashCode();
+    }
+
+    @Override
+    public boolean equals(final @Nullable Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof PatternExpression)) {
+            return false;
+        }
+        final PatternExpression other = (PatternExpression) obj;
+        return regex.equals(other.regex) && pattern.equals(other.pattern);
+    }
+
+    @Override
+    public String toString() {
+        return regex;
+    }
+}