Add query language interpreter code

1 files changed, 51 insertions, 0 deletions

diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/interpreter/Environment.java b/src/main/java/pl/edu/mimuw/cloudatlas/interpreter/Environment.java
new file mode 100644
index 0000000..d45b600
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/interpreter/Environment.java
@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) 2014, University of Warsaw
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are permitted
+ * provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ * conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
+ * conditions and the following disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ *
+ * 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 HOLDER 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.
+ */
+
+package pl.edu.mimuw.cloudatlas.interpreter;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import pl.edu.mimuw.cloudatlas.model.ValueNull;
+
+class Environment {
+	private final TableRow row;
+	private final Map<String, Integer> columns = new HashMap<String, Integer>();
+
+	public Environment(TableRow row, List<String> columns) {
+		this.row = row;
+		int i = 0;
+		for(String c : columns)
+			this.columns.put(c, i++);
+	}
+
+	public Result getIdent(String ident) {
+		try {
+			return new ResultSingle(row.getIth(columns.get(ident)));
+		} catch(NullPointerException exception) {
+			return new ResultSingle(ValueNull.getInstance());
+		}
+	}
+}