Add query language interpreter code

1 files changed, 123 insertions, 0 deletions

diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/interpreter/Table.java b/src/main/java/pl/edu/mimuw/cloudatlas/interpreter/Table.java
new file mode 100644
index 0000000..9f2e1d9
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/interpreter/Table.java
@@ -0,0 +1,123 @@
+/**
+ * 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.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.Map.Entry;
+
+import pl.edu.mimuw.cloudatlas.model.Attribute;
+import pl.edu.mimuw.cloudatlas.model.Type;
+import pl.edu.mimuw.cloudatlas.model.TypeCollection;
+import pl.edu.mimuw.cloudatlas.model.Value;
+import pl.edu.mimuw.cloudatlas.model.ValueList;
+import pl.edu.mimuw.cloudatlas.model.ValueNull;
+import pl.edu.mimuw.cloudatlas.model.ZMI;
+
+public class Table implements Iterable<TableRow> {
+	private final List<String> columns = new ArrayList<String>();
+	private final Map<String, Integer> headersMap = new HashMap<String, Integer>();
+	private final List<TableRow> rows = new ArrayList<TableRow>();
+
+	// creates whole table based on a given ZMI
+	public Table(ZMI zmi) {
+		Set<String> allColumns = new HashSet<String>();
+		for(ZMI z : zmi.getSons())
+			for(Entry<Attribute, Value> e : z.getAttributes())
+				allColumns.add(e.getKey().getName());
+
+		columns.addAll(allColumns);
+		int i = 0;
+		for(String c : columns)
+			headersMap.put(c, i++);
+		for(ZMI z : zmi.getSons()) {
+			Value[] row = new Value[columns.size()];
+			for(int j = 0; j < row.length; ++j)
+				row[j] = ValueNull.getInstance();
+			for(Entry<Attribute, Value> e : z.getAttributes())
+				row[getColumnIndex(e.getKey().getName())] = e.getValue();
+			appendRow(new TableRow(row));
+		}
+	}
+
+	// creates an empty table with same columns as given
+	public Table(Table table) {
+		this.columns.addAll(table.columns);
+		this.headersMap.putAll(table.headersMap);
+	}
+
+	public List<String> getColumns() {
+		return Collections.unmodifiableList(columns);
+	}
+
+	public void appendRow(TableRow row) {
+		if(row.getSize() != columns.size())
+			throw new InternalInterpreterException("Cannot append row. Length expected: " + columns.size() + ", got: "
+					+ row.getSize() + ".");
+		rows.add(row);
+	}
+
+	public int getColumnIndex(String column) {
+		try {
+			return headersMap.get(column).intValue();
+		} catch(NullPointerException exception) {
+			throw new NoSuchAttributeException(column);
+		}
+	}
+
+	public ValueList getColumn(String column) {
+		if(column.startsWith("&")) {
+			throw new NoSuchAttributeException(column);
+		}
+		try {
+			int position = headersMap.get(column);
+			List<Value> result = new ArrayList<Value>();
+			for(TableRow row : rows) {
+				Value v = row.getIth(position);
+				result.add(v);
+			}
+			Type elementType = TypeCollection.computeElementType(result);
+			return new ValueList(result, elementType);
+		} catch(NullPointerException exception) {
+			throw new NoSuchAttributeException(column);
+		}
+	}
+
+	@Override
+	public Iterator<TableRow> iterator() {
+		return rows.iterator();
+	}
+
+	public void sort(Comparator<TableRow> comparator) {
+		Collections.sort(rows, comparator);
+	}
+}