[Lada-commits] [PATCH 2 of 4] Added JSON object type to database dialect

Wald Commits scm-commit at wald.intevation.org
Fri Feb 24 14:29:30 CET 2017


# HG changeset patch
# User Raimund Renkert <raimund.renkert at intevation.de>
# Date 1487942899 -3600
# Node ID 0eece233cbaee2f10b84845294219adad6be4438
# Parent  ba47994c1665b30b2ae3719e2aa65f6c64732ce2
Added JSON object type to database dialect.

diff -r ba47994c1665 -r 0eece233cbae src/main/java/de/intevation/lada/util/data/JsonObjectType.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/de/intevation/lada/util/data/JsonObjectType.java	Fri Feb 24 14:28:19 2017 +0100
@@ -0,0 +1,207 @@
+/* Copyright (C) 2013 by Bundesamt fuer Strahlenschutz
+ * Software engineering by Intevation GmbH
+ *
+ * This file is Free Software under the GNU GPL (v>=3)
+ * and comes with ABSOLUTELY NO WARRANTY! Check out
+ * the documentation coming with IMIS-Labordaten-Application for details.
+ */
+package de.intevation.lada.util.data;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Types;
+
+import org.hibernate.HibernateException;
+import org.hibernate.engine.spi.SessionImplementor;
+import org.hibernate.usertype.UserType;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * Implementation for a new data type in the postgresql/postgis jdbc driver.
+ *
+ * @author <a href="mailto:rrenkert at intevation.de">Raimund Renkert</a>
+ */
+public class JsonObjectType implements UserType {
+    /**
+     * Reconstruct an object from the cacheable representation. At the very
+     * least this method should perform a deep copy if the type is mutable.
+     * (optional <span id="IL_AD5" class="IL_AD">operation</span>)
+     *
+     * @param cached
+     *            the object to be cached
+     * @param owner
+     *            the owner of the cached object
+     * @return a reconstructed object from the cachable representation
+     * @throws HibernateException
+     */
+    @Override
+    public Object assemble(Serializable cached, Object owner) throws HibernateException {
+        return this.deepCopy(cached);
+    }
+
+    /**
+     * Return a deep copy of the persistent state, stopping at entities and st
+     * collections. It is not necessary to copy immutable objects, or null
+     * values, in which case it is safe to simple return the argument.
+     *
+     * @param value
+     *            the object to be cloned, which may be null
+     *
+     * @return object a copy
+     * @throws HibernateException
+     */
+    @Override
+    public Object deepCopy(Object value) throws HibernateException {
+        return value;
+    }
+
+    /**
+     * Transform the object into its cacheable representation. At the very least
+     * this method should perform a deep copy if the type is mutable. That may
+     * not be enough for some implementations, however; for example,
+     * <span id="IL_AD11" class="IL_AD">associations</span> must be cached as <span id="IL_AD9" class="IL_AD">identifier</span> values. (optional operation)
+     *
+     * @param value
+     *            the object to be cached
+     * @return a cachable representation of the object
+     * @throws HibernateException
+     */
+    @Override
+    public Serializable disassemble(Object value) throws HibernateException {
+        return (String) this.deepCopy(value);
+    }
+
+    /**
+     * Compare two instances of the class mapped by this type for persistence
+     * "equality". Equality of the persistence state.
+     *
+     * @param x
+     * @param y
+     * @return <span id="IL_AD12" class="IL_AD">boolean</span>
+     * @throws HibernateException
+     */
+    @Override
+    public boolean equals(Object x, Object y) throws HibernateException {
+        if (x == null) {
+            return y == null;
+        }
+        return x.equals(y);
+    }
+
+    /**
+     * Get a hashcode for the instance, consistent with persistence "equality".
+     */
+    @Override
+    public int hashCode(Object x) throws HibernateException {
+        return x.hashCode();
+    }
+
+    /**
+     * Are objects of this type mutable?
+     *
+     * @return boolean
+     */
+    @Override
+    public boolean isMutable() {
+        return true;
+    }
+
+    /**
+     * Retrieve an instance of the mapped class from a JDBC resultset.
+     * Implementors should handle possibility of null values.
+     *
+     * @param rs
+     *            a JDBC result set
+     * @param names
+     *            the column names
+     * @param session
+     * @param owner
+     *            the containing entity
+     * @return
+     * @throws HibernateException
+     * @throws SQLException
+     */
+    @Override
+    public Object nullSafeGet(ResultSet rs, String[] names, SessionImplementor session, Object owner) throws HibernateException, SQLException {
+        ObjectMapper mapper = new ObjectMapper();
+        JsonNode node = null;
+        try {
+            node = mapper.readTree(rs.getString(names[0]));
+            return node;
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return mapper.createObjectNode();
+    }
+
+    /**
+     * Write an instance of the mapped class to a prepared statement.
+     * Implementors should handle possibility of null values. A multi-column
+     * type should be written to parameters starting from <tt>index</tt>
+     *
+     * @param st
+     *            a JDBC prepared statement
+     * @param value
+     *            the object to write
+     * @param index
+     *            statement parameter index
+     * @param session
+     * @throws HibernateException
+     * @throws SQLException
+     */
+    @Override
+    public void nullSafeSet(PreparedStatement st, Object value, int index, SessionImplementor session) throws HibernateException, SQLException {
+        if (value == null) {
+            st.setNull(index, Types.OTHER);
+            return;
+        }
+        st.setObject(index, value, Types.OTHER);
+    }
+
+    /**
+     * During merge, <span id="IL_AD7" class="IL_AD">replace</span> the existing (target) values in the entity we are
+     * merging to with a new (original) value from the detched entity we are
+     * merging. For immutable objects, or null values, it is safe to return a
+     * copy of the first parameter. For the objects with component values, it
+     * might make sense to recursively replace component values
+     *
+     * @param original
+     *            the value from the detched entity being merged
+     * @param target
+     *            the value in the managed entity
+     * @param owner
+     * @return the value to be merged
+     * @throws HibernateException
+     */
+    @Override
+    public Object replace(Object original, Object target, Object owner) throws HibernateException {
+        return original;
+    }
+
+    /**
+     * The class returned by <tt>nullSafeGet()</tt>
+     *
+     * @return Class
+     */
+    @Override
+    public Class returnedClass() {
+        return String.class;
+    }
+
+    /**
+     * Returns the SQL type <span id="IL_AD3" class="IL_AD">codes</span> for the columns mapped by this type. The codes
+     * are defined on <tt>java.sql.Types</tt>
+     *
+     * @return int[] the typecodes
+     * @see java.sql.Types
+     */
+    @Override
+    public int[] sqlTypes() {
+        return new int[] { Types.JAVA_OBJECT };
+    }
+}
diff -r ba47994c1665 -r 0eece233cbae src/main/java/de/intevation/lada/util/data/LadaPostgisDialect.java
--- a/src/main/java/de/intevation/lada/util/data/LadaPostgisDialect.java	Fri Feb 24 14:27:10 2017 +0100
+++ b/src/main/java/de/intevation/lada/util/data/LadaPostgisDialect.java	Fri Feb 24 14:28:19 2017 +0100
@@ -23,5 +23,6 @@
     public LadaPostgisDialect() {
         super();
         this.registerColumnType(Types.ARRAY, "integer[]");
+        this.registerColumnType(Types.JAVA_OBJECT, "json");
     }
 }


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