#919 - io.ebean package initial

src/main/java/io/ebeaninternal/server/util/ArrayStack.java

@@ -0,0 +1,93 @@
+package io.ebeaninternal.server.util;
+
+import java.util.ArrayList;
+import java.util.EmptyStackException;
+
+/**
+ * Stack based on ArrayList.
+ *
+ * @author rbygrave
+ */
+public class ArrayStack<E> {
+
+  private final ArrayList<E> list;
+
+  /**
+   * Creates an empty Stack with an initial size.
+   */
+  public ArrayStack(int size) {
+    this.list = new ArrayList<>(size);
+  }
+
+  /**
+   * Creates an empty Stack.
+   */
+  public ArrayStack() {
+    this.list = new ArrayList<>();
+  }
+
+  public String toString() {
+    return list.toString();
+  }
+
+  /**
+   * Pushes an item onto the top of this stack.
+   */
+  public void push(E item) {
+    list.add(item);
+  }
+
+  /**
+   * Removes the object at the top of this stack and returns that object as
+   * the value of this function.
+   */
+  public E pop() {
+    int len = list.size();
+    if (len == 0) {
+      throw new EmptyStackException();
+    }
+    return list.remove(len - 1);
+  }
+
+  protected E peekZero(boolean retNull) {
+    int len = list.size();
+    if (len == 0) {
+      if (retNull) {
+        return null;
+      }
+      throw new EmptyStackException();
+    }
+    return list.get(len - 1);
+  }
+
+  /**
+   * Returns the object at the top of this stack without removing it.
+   */
+  public E peek() {
+    return peekZero(false);
+  }
+
+  /**
+   * Returns the object at the top of this stack without removing it.
+   * If the stack is empty this returns null.
+   */
+  public E peekWithNull() {
+    return peekZero(true);
+  }
+
+  /**
+   * Tests if this stack is empty.
+   */
+  public boolean isEmpty() {
+    return list.isEmpty();
+  }
+
+  public int size() {
+    return list.size();
+  }
+
+  public boolean contains(Object o) {
+    //noinspection SuspiciousMethodCalls
+    return list.contains(o);
+  }
+}