package timeflow.data.db;
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import java.util.*;
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// methods are public for testing purposes.
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public class Schema implements Iterable<Field>
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{
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private Map<String, Field> schema = new HashMap<String, Field>();
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private List<Field> fieldList = new ArrayList<Field>(); // so we preserve field order.
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public Iterator<Field> iterator()
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{
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return fieldList.iterator();
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}
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public Field getField(String key)
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{
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return schema.get(key);
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}
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public List<String> getKeys()
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{
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return new ArrayList(schema.keySet());
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}
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public List<Field> getFields(Class type)
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{
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List<Field> a = new ArrayList<Field>();
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for (Field s : fieldList)
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{
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if (type == null || s.getType() == type)
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{
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a.add(s);
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}
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}
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return a;
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}
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public List<Field> getFields()
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{
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return getFields(null);
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}
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// not sure this actually works! removing things while iterating? to-do: test!
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public void delete(Field field)
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{
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if (schema.get(field.getName()) == null)
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{
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throw new IllegalArgumentException("No field exists: " + field);
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}
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Set<String> keys = new HashSet<String>(schema.keySet());
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for (String s : keys)
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{
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Field f = schema.get(s);
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if (f == field)
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{
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schema.remove(s);
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}
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}
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fieldList.remove(field);
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}
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public void addAlias(Field field, String name)
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{
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if (field == null)
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{
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schema.remove(name);
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return;
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}
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if (!schema.values().contains(field))
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{
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throw new IllegalArgumentException("Field does not exist in schema: " + field);
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}
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schema.put(name, field);
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}
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public Field add(String name, Class type)
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{
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return add(new Field(name, type));
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}
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public Field add(Field field)
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{
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if (schema.get(field.getName()) != null)
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{
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throw new IllegalArgumentException("Schema already has field named '" + field.getName()
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+ "', type=" + field.getType());
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}
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schema.put(field.getName(), field);
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fieldList.add(field);
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return field;
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}
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public void setNewFieldOrder(List<Field> newOrder)
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{
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// first, we go through and check that this really is a new ordering!
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if (newOrder.size() != fieldList.size())
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{
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throw new IllegalArgumentException("Field lists have different sizes");
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}
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for (Field f : newOrder)
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{
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if (!fieldList.contains(f))
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{
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throw new IllegalArgumentException("New field list has unexpected field: " + f);
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}
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}
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fieldList = newOrder;
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}
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public void print()
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{
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System.out.println(schema);
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}
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public void renameField(Field field, String name)
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{
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Field old = schema.get(name);
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if (old != null && old != field)
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{
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throw new IllegalArgumentException("Can't rename a field to a name that already exists: " + name);
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}
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schema.remove(field);
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field.setName(name);
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schema.put(name, field);
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}
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}
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