1 files changed, 178 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/expression/Member.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/expression/Member.java
new file mode 100644
index 000000000..5d442f62c
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/expression/Member.java
@@ -0,0 +1,178 @@
+/*******************************************************************************
+ * Copyright (c) 2009 Cloudsmith Inc. and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Cloudsmith Inc. - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.internal.p2.metadata.expression;
+
+import java.lang.reflect.*;
+import org.eclipse.equinox.p2.metadata.expression.IEvaluationContext;
+import org.eclipse.equinox.p2.metadata.expression.IExpressionVisitor;
+
+/**
+ * <p>An expression that performs member calls to obtain some value
+ * from some object instance. It uses standard bean semantics so
+ * that an attempt to obtain &quot;value&quot; will cause an
+ * attempt to call <code>getValue()</code> and if no such method
+ * exists, <code>isValue()</code> and if that doesn't work either,
+ * <code>value()</code>.</p>
+ */
+public abstract class Member extends Unary {
+
+	public static final class DynamicMember extends Member {
+		private static final String GET_PREFIX = "get"; //$NON-NLS-1$
+		private static final String IS_PREFIX = "is"; //$NON-NLS-1$
+		private static final Class<?>[] NO_ARG_TYPES = new Class[0];
+
+		private Class<?> lastClass;
+
+		private Method method;
+		private String methodName;
+
+		DynamicMember(Expression operand, String name) {
+			super(operand, name, Expression.emptyArray);
+			if (!(name.startsWith(GET_PREFIX) || name.startsWith(IS_PREFIX)))
+				name = GET_PREFIX + Character.toUpperCase(name.charAt(0)) + name.substring(1);
+			this.methodName = name;
+		}
+
+		public Object evaluate(IEvaluationContext context) {
+			return invoke(operand.evaluate(context));
+		}
+
+		public Object invoke(Object self) {
+			if (self == null)
+				throw new IllegalArgumentException("Cannot access member \'" + name + "\' in null"); //$NON-NLS-1$//$NON-NLS-2$
+
+			if (self instanceof MemberProvider)
+				return ((MemberProvider) self).getMember(name);
+
+			Class<?> c = self.getClass();
+			if (lastClass == null || !lastClass.isAssignableFrom(c)) {
+				Method m;
+				for (;;) {
+					try {
+						m = c.getMethod(methodName, NO_ARG_TYPES);
+						if (!Modifier.isPublic(m.getModifiers()))
+							throw new NoSuchMethodException();
+						break;
+					} catch (NoSuchMethodException e) {
+						if (methodName.startsWith(GET_PREFIX))
+							// Switch from using getXxx() to isXxx()
+							methodName = IS_PREFIX + Character.toUpperCase(name.charAt(0)) + name.substring(1);
+						else if (methodName.startsWith(IS_PREFIX))
+							// Switch from using isXxx() to xxx()
+							methodName = name;
+						else
+							throw new IllegalArgumentException("Cannot find a public member \'" + name + "\' in a " + self.getClass().getName()); //$NON-NLS-1$//$NON-NLS-2$
+					}
+				}
+
+				// Since we already checked that it's public. This will speed
+				// up the calls a bit.
+				m.setAccessible(true);
+				lastClass = c;
+				method = m;
+			}
+
+			Exception checked;
+			try {
+				return method.invoke(self, NO_ARGS);
+			} catch (IllegalArgumentException e) {
+				throw e;
+			} catch (IllegalAccessException e) {
+				checked = e;
+			} catch (InvocationTargetException e) {
+				Throwable cause = e.getTargetException();
+				if (cause instanceof RuntimeException)
+					throw (RuntimeException) cause;
+				if (cause instanceof Error)
+					throw (Error) cause;
+				checked = (Exception) cause;
+			}
+			throw new RuntimeException("Problem invoking " + methodName + " on a " + self.getClass().getName(), checked); //$NON-NLS-1$ //$NON-NLS-2$
+		}
+	}
+
+	static final Object[] NO_ARGS = new Object[0];
+
+	static Member createDynamicMember(Expression operand, String name) {
+		return new DynamicMember(operand, name);
+	}
+
+	protected final Expression[] argExpressions;
+
+	final String name;
+
+	protected Member(Expression operand, String name, Expression[] args) {
+		super(operand);
+		this.name = name;
+		this.argExpressions = args;
+	}
+
+	public boolean accept(IExpressionVisitor visitor) {
+		if (super.accept(visitor))
+			for (int idx = 0; idx < argExpressions.length; ++idx)
+				if (!argExpressions[idx].accept(visitor))
+					return false;
+		return true;
+	}
+
+	public int compareTo(Expression e) {
+		int cmp = super.compareTo(e);
+		if (cmp == 0) {
+			cmp = name.compareTo(((Member) e).name);
+			if (cmp == 0)
+				cmp = compare(argExpressions, ((Member) e).argExpressions);
+		}
+		return cmp;
+	}
+
+	public boolean equals(Object o) {
+		if (super.equals(o)) {
+			Member mo = (Member) o;
+			return name.equals(mo.name) && equals(argExpressions, mo.argExpressions);
+		}
+		return false;
+	}
+
+	public int getExpressionType() {
+		return TYPE_MEMBER;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public String getOperator() {
+		return OPERATOR_MEMBER;
+	}
+
+	public int getPriority() {
+		return PRIORITY_MEMBER;
+	}
+
+	public int hashCode() {
+		int result = 31 + name.hashCode();
+		result = 31 * result + operand.hashCode();
+		return 31 * result + hashCode(argExpressions);
+	}
+
+	public void toString(StringBuffer bld, Variable rootVariable) {
+		if (operand != rootVariable) {
+			appendOperand(bld, rootVariable, operand, getPriority());
+			bld.append('.');
+		}
+		bld.append(name);
+		if (argExpressions.length > 0) {
+			bld.append('(');
+			elementsToString(bld, rootVariable, argExpressions);
+			bld.append(')');
+		}
+	}
+}