add abstraction class for asset identifiers

lib/Doctrine/DBAL/Schema/Identifier.php

+<?php
+/*
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the MIT license. For more information, see
+ * <http://www.doctrine-project.org>.
+ */
+
+namespace Doctrine\DBAL\Schema;
+
+use Doctrine\DBAL\Schema\AbstractAsset;
+
+/**
+ * An abstraction class for an asset identifier.
+ *
+ * Wraps identifier names like column names in indexes / foreign keys
+ * in an abstract class for proper quotation capabilities.
+ *
+ * @author Steve Müller <st.mueller@dzh-online.de>
+ * @link   www.doctrine-project.org
+ * @since  2.4
+ */
+class Identifier extends AbstractAsset
+{
+    /**
+     * Constructor.
+     *
+     * @param string $identifier Identifier name to wrap.
+     */
+    public function __construct($identifier)
+    {
+        $this->_setName($identifier);
+    }
+}
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