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package oracle.toplink.essentials.internal.expressions;
import java.io.*;
import oracle.toplink.essentials.internal.helper.*;
/**
* INTERNAL:
* Represents the aliased tables an ObjectExpression will be translated to,
* along with any of its derived TableExpressions.
* For bug 2778339 / CR 2456, this Lookup also represents identity. Two
* expressions with the same Lookup will be translated to the same table(s).
*/
public class TableAliasLookup implements Serializable {// CR#3718, implements Serializable
protected DatabaseTable[] keys;
protected DatabaseTable[] values;
protected int lastUsed;
/* Have these aliases already been added to a FROM clause? */
protected boolean haveBeenAddedToStatement;
/**
* TableAliasLookup constructor comment.
*/
public TableAliasLookup() {
super();
keys = new DatabaseTable[5];
values = new DatabaseTable[5];
lastUsed = 0;
}
/**
* TableAliasLookup constructor comment.
*/
public TableAliasLookup(int initialSize) {
super();
keys = new DatabaseTable[initialSize];
values = new DatabaseTable[initialSize];
lastUsed = 0;
}
// Add all of our values to the hashtable
public void addToHashtable(java.util.Hashtable aHashTable) {
for (int i = 0; i < lastUsed; i++) {
aHashTable.put(keys[i], values[i]);
}
}
public DatabaseTable get(DatabaseTable key) {
int index = lookupIndexOf(key);
if (index == -1) {
return null;
}
return values[index];
}
private void grow() {
DatabaseTable[] newKeys = new DatabaseTable[(lastUsed * 2)];
DatabaseTable[] newValues = new DatabaseTable[(lastUsed * 2)];
for (int i = 0; i < lastUsed; i++) {
newKeys[i] = keys[i];
newValues[i] = values[i];
}
keys = newKeys;
values = newValues;
}
/**
* INTERNAL:
* Answers if the aliases have already been added to a statement.
* This insures that a subselect will not re-add aliases already
* in a parent FROM clause.
* For CR#4223
*/
public boolean haveBeenAddedToStatement() {
return haveBeenAddedToStatement;
}
/**
* isEmpty method comment.
*/
public boolean isEmpty() {
return keys[0] == null;
}
public DatabaseTable keyAtValue(DatabaseTable value) {
int index = lookupValueIndexOf(value);
if (index == -1) {
return null;
}
return keys[index];
}
public DatabaseTable[] keys() {
return keys;
}
private int lookupIndexOf(DatabaseTable table) {
for (int i = 0; i < lastUsed; i++) {
if (keys[i].equals(table)) {
return i;
}
}
return -1;
}
private int lookupValueIndexOf(DatabaseTable table) {
for (int i = 0; i < lastUsed; i++) {
if (values[i].equals(table)) {
return i;
}
}
return -1;
}
/**
* put method comment.
*/
public DatabaseTable put(DatabaseTable key, DatabaseTable value) {
int index = lookupIndexOf(key);
if (index == -1) {
keys[lastUsed] = key;
values[lastUsed++] = value;
if (lastUsed >= keys.length) {
grow();
}
} else {
values[index] = value;
}
return value;
}
/**
* INTERNAL:
* Called when aliases are added to a statement.
* This insures that a subselect will not re-add aliases already
* in a parent FROM clause.
* For CR#4223
*/
public void setHaveBeenAddedToStatement(boolean value) {
haveBeenAddedToStatement = value;
}
/**
* size method comment.
*/
public int size() {
return lastUsed;
}
public String toString() {
int max = size() - 1;
StringBuffer buf = new StringBuffer();
buf.append("{");
for (int i = 0; i <= max; i++) {
String s1 = keys[i].toString();
String s2 = values[i].toString();
buf.append(s1 + "=" + s2);
if (i < max) {
buf.append(", ");
}
}
buf.append("}");
return buf.toString();
}
public DatabaseTable[] values() {
return values;
}
}
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