add pair&triple

src/main/java/com/jd/jdbc/common/tuple/ImmutablePair.java

@@ -0,0 +1,210 @@
+/*
+ * 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 com.jd.jdbc.common.tuple;
+
+import java.util.Map;
+
+/**
+ * <p>An immutable pair consisting of two {@code Object} elements.</p>
+ *
+ * <p>Although the implementation is immutable, there is no restriction on the objects
+ * that may be stored. If mutable objects are stored in the pair, then the pair
+ * itself effectively becomes mutable. The class is also {@code final}, so a subclass
+ * can not add undesirable behavior.</p>
+ *
+ * <p>#ThreadSafe# if both paired objects are thread-safe</p>
+ *
+ * @param <L> the left element type
+ * @param <R> the right element type
+ * @since 3.0
+ */
+public final class ImmutablePair<L, R> extends Pair<L, R> {
+
+    /**
+     * An empty array.
+     * <p>
+     * Consider using {@link #emptyArray()} to avoid generics warnings.
+     * </p>
+     *
+     * @since 3.10.
+     */
+    public static final ImmutablePair<?, ?>[] EMPTY_ARRAY = new ImmutablePair[0];
+
+    /**
+     * An immutable pair of nulls.
+     */
+    // This is not defined with generics to avoid warnings in call sites.
+    @SuppressWarnings("rawtypes")
+    private static final ImmutablePair NULL = of(null, null);
+
+    /**
+     * Serialization version
+     */
+    private static final long serialVersionUID = 4954918890077093841L;
+
+    /**
+     * Returns the empty array singleton that can be assigned without compiler warning.
+     *
+     * @param <L> the left element type
+     * @param <R> the right element type
+     * @return the empty array singleton that can be assigned without compiler warning.
+     * @since 3.10.
+     */
+    @SuppressWarnings("unchecked")
+    public static <L, R> ImmutablePair<L, R>[] emptyArray() {
+        return (ImmutablePair<L, R>[]) EMPTY_ARRAY;
+    }
+
+    /**
+     * <p>Creates an immutable pair of two objects inferring the generic types.</p>
+     *
+     * <p>This factory allows the pair to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L>  the left element type
+     * @param <R>  the right element type
+     * @param left the left element, may be null
+     * @return a pair formed from the two parameters, not null
+     * @since 3.11
+     */
+    public static <L, R> Pair<L, R> left(final L left) {
+        return ImmutablePair.of(left, null);
+    }
+
+    /**
+     * Returns an immutable pair of nulls.
+     *
+     * @param <L> the left element of this pair. Value is {@code null}.
+     * @param <R> the right element of this pair. Value is {@code null}.
+     * @return an immutable pair of nulls.
+     * @since 3.6
+     */
+    public static <L, R> ImmutablePair<L, R> nullPair() {
+        return NULL;
+    }
+
+    /**
+     * <p>Creates an immutable pair of two objects inferring the generic types.</p>
+     *
+     * <p>This factory allows the pair to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L>   the left element type
+     * @param <R>   the right element type
+     * @param left  the left element, may be null
+     * @param right the right element, may be null
+     * @return a pair formed from the two parameters, not null
+     */
+    public static <L, R> ImmutablePair<L, R> of(final L left, final R right) {
+        return new ImmutablePair<>(left, right);
+    }
+
+    /**
+     * <p>Creates an immutable pair from an existing pair.</p>
+     *
+     * <p>This factory allows the pair to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L>  the left element type
+     * @param <R>  the right element type
+     * @param pair the existing pair.
+     * @return a pair formed from the two parameters, not null
+     * @since 3.10
+     */
+    public static <L, R> ImmutablePair<L, R> of(final Map.Entry<L, R> pair) {
+        final L left;
+        final R right;
+        if (pair != null) {
+            left = pair.getKey();
+            right = pair.getValue();
+        } else {
+            left = null;
+            right = null;
+        }
+        return new ImmutablePair<>(left, right);
+    }
+
+    /**
+     * <p>Creates an immutable pair of two objects inferring the generic types.</p>
+     *
+     * <p>This factory allows the pair to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L>   the left element type
+     * @param <R>   the right element type
+     * @param right the right element, may be null
+     * @return a pair formed from the two parameters, not null
+     * @since 3.11
+     */
+    public static <L, R> Pair<L, R> right(final R right) {
+        return ImmutablePair.of(null, right);
+    }
+
+    /**
+     * Left object
+     */
+    public final L left;
+
+    /**
+     * Right object
+     */
+    public final R right;
+
+    /**
+     * Create a new pair instance.
+     *
+     * @param left  the left value, may be null
+     * @param right the right value, may be null
+     */
+    public ImmutablePair(final L left, final R right) {
+        super();
+        this.left = left;
+        this.right = right;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public L getLeft() {
+        return left;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public R getRight() {
+        return right;
+    }
+
+    /**
+     * <p>Throws {@code UnsupportedOperationException}.</p>
+     *
+     * <p>This pair is immutable, so this operation is not supported.</p>
+     *
+     * @param value the value to set
+     * @return never
+     * @throws UnsupportedOperationException as this operation is not supported
+     */
+    @Override
+    public R setValue(final R value) {
+        throw new UnsupportedOperationException();
+    }
+
+}

src/main/java/com/jd/jdbc/common/tuple/ImmutableTriple.java

@@ -0,0 +1,159 @@
+/*
+ * 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 com.jd.jdbc.common.tuple;
+
+/**
+ * <p>An immutable triple consisting of three {@code Object} elements.</p>
+ *
+ * <p>Although the implementation is immutable, there is no restriction on the objects
+ * that may be stored. If mutable objects are stored in the triple, then the triple
+ * itself effectively becomes mutable. The class is also {@code final}, so a subclass
+ * can not add undesirable behavior.</p>
+ *
+ * <p>#ThreadSafe# if all three objects are thread-safe</p>
+ *
+ * @param <L> the left element type
+ * @param <M> the middle element type
+ * @param <R> the right element type
+ * @since 3.2
+ */
+public final class ImmutableTriple<L, M, R> extends Triple<L, M, R> {
+
+    /**
+     * An empty array.
+     * <p>
+     * Consider using {@link #emptyArray()} to avoid generics warnings.
+     * </p>
+     *
+     * @since 3.10.
+     */
+    public static final ImmutableTriple<?, ?, ?>[] EMPTY_ARRAY = new ImmutableTriple[0];
+
+    /**
+     * An immutable triple of nulls.
+     */
+    // This is not defined with generics to avoid warnings in call sites.
+    @SuppressWarnings("rawtypes")
+    private static final ImmutableTriple NULL = of(null, null, null);
+
+    /**
+     * Serialization version
+     */
+    private static final long serialVersionUID = 1L;
+
+    /**
+     * Returns the empty array singleton that can be assigned without compiler warning.
+     *
+     * @param <L> the left element type
+     * @param <M> the middle element type
+     * @param <R> the right element type
+     * @return the empty array singleton that can be assigned without compiler warning.
+     * @since 3.10.
+     */
+    @SuppressWarnings("unchecked")
+    public static <L, M, R> ImmutableTriple<L, M, R>[] emptyArray() {
+        return (ImmutableTriple<L, M, R>[]) EMPTY_ARRAY;
+    }
+
+    /**
+     * Returns an immutable triple of nulls.
+     *
+     * @param <L> the left element of this triple. Value is {@code null}.
+     * @param <M> the middle element of this triple. Value is {@code null}.
+     * @param <R> the right element of this triple. Value is {@code null}.
+     * @return an immutable triple of nulls.
+     * @since 3.6
+     */
+    public static <L, M, R> ImmutableTriple<L, M, R> nullTriple() {
+        return NULL;
+    }
+
+    /**
+     * <p>Obtains an immutable triple of three objects inferring the generic types.</p>
+     *
+     * <p>This factory allows the triple to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L>    the left element type
+     * @param <M>    the middle element type
+     * @param <R>    the right element type
+     * @param left   the left element, may be null
+     * @param middle the middle element, may be null
+     * @param right  the right element, may be null
+     * @return a triple formed from the three parameters, not null
+     */
+    public static <L, M, R> ImmutableTriple<L, M, R> of(final L left, final M middle, final R right) {
+        return new ImmutableTriple<>(left, middle, right);
+    }
+
+    /**
+     * Left object
+     */
+    public final L left;
+
+    /**
+     * Middle object
+     */
+    public final M middle;
+
+    /**
+     * Right object
+     */
+    public final R right;
+
+    /**
+     * Create a new triple instance.
+     *
+     * @param left   the left value, may be null
+     * @param middle the middle value, may be null
+     * @param right  the right value, may be null
+     */
+    public ImmutableTriple(final L left, final M middle, final R right) {
+        super();
+        this.left = left;
+        this.middle = middle;
+        this.right = right;
+    }
+
+    //-----------------------------------------------------------------------
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public L getLeft() {
+        return left;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public M getMiddle() {
+        return middle;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public R getRight() {
+        return right;
+    }
+}
+