Class for unresolved inherited-property-value() calls.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/FOP_0-20-0_Alt-Design@195189 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/src/org/apache/fop/datatypes/InheritedValue.java b/src/org/apache/fop/datatypes/InheritedValue.java
new file mode 100644 (file)
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+++ b/src/org/apache/fop/datatypes/InheritedValue.java
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+package org.apache.fop.datatypes;
+
+import org.apache.fop.fo.expr.PropertyException;
+import org.apache.fop.fo.expr.PropertyValue;
+import org.apache.fop.fo.expr.PropertyTriplet;
+import org.apache.fop.fo.Properties;
+import org.apache.fop.datatypes.IndirectValue;
+
+/*
+ * $Id$
+ *
+ * Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
+ * For details on use and redistribution please refer to the
+ * LICENSE file included with these sources.
+ * @author <a href="mailto:pbwest@powerup.com.au">Peter B. West</a>
+ * @version $Revision$ $Name$
+ */
+/**
+ * A class representing an unresolved inherited value.  It may be created as
+ * in the process of resolving "normal" default inheritance, when no value is
+ * specified for an inheritable property, or it may be created in the process
+ * of resolving a call to the core function
+ * <tt>inherited-property-value()</tt>.  In both cases, it will only be
+ * necessary when the inherited property cannot otherwise be resolved into a
+ * <tt>PropertyValue<tt> immediately.
+ * <p>Strictly speaking, a distinction should be made between these two
+ * cases, because the latter may derive from a property other than the
+ * target property whose value ist is resolving.  This is never true of
+ * default inheritance.
+ * <p><tt>InheritedValue</tt> differs from <tt>Inherit</tt> in that it only
+ * applies to properties which support default inheritance, and there is at
+ * least one case - that of <i>line-height</i> defined as a &lt;number&gt; -
+ * in which the specified value is inherited.
+ */
+
+public class InheritedValue extends IndirectValue {
+
+    private static final String tag = "$Name$";
+    private static final String revision = "$Revision$";
+
+    /**
+     * @param property the <tt>int</tt> index of the property on which
+     * this value is being defined.
+     * @param sourceProperty the <tt>int</tt> index of the property from
+     * which the inherited value is derived.
+     * @exception PropertyException
+     */
+    public InheritedValue(int property, int sourceProperty)
+        throws PropertyException
+    {
+        super(property, PropertyValue.INHERIT, sourceProperty);
+    }
+
+    /**
+     * @param property the <tt>int</tt> index of the property on which
+     * this value is being defined.
+     * @exception PropertyException
+     */
+    public InheritedValue(int property)
+        throws PropertyException
+    {
+        this(property, property);
+    }
+
+    /**
+     * @param propertyName the <tt>String</tt> name of the property on which
+     * this value is being defined.
+     * @param sourcePropertyName the <tt>String</tt> name of the property
+     * from which the inherited value is derived.
+     * @exception PropertyException
+     */
+    public InheritedValue(String propertyName, String sourcePropertyName)
+        throws PropertyException
+    {
+        super(propertyName, PropertyValue.INHERIT, sourcePropertyName);
+    }
+
+    /**
+     * @param propertyName the <tt>String</tt> name of the property on which
+     * this value is being defined.
+     * @exception PropertyException
+     */
+    public InheritedValue(String propertyName)
+        throws PropertyException
+    {
+        this(propertyName, propertyName);
+    }
+
+    /**
+     * validate the <i>InheritedValue</i> against the associated property.
+     */
+    public void validate(int property) throws PropertyException {
+        String propStr = "Unknown";
+        String spropStr = "Unknown";
+        int sprop = getSourceProperty();
+        if (property != sprop) {
+            try {
+                propStr = PropNames.getPropertyName(this.property);
+                spropStr = PropNames.getPropertyName(sprop);
+            } catch (PropertyException e) {}
+            throw new PropertyException
+                    ("InheritedValue for property " + this.property
+                     + " (" + propStr + ") can only be validated against its "
+                     + "source property " + sprop + " (" + spropStr + ").");
+        }
+        // Property must be inheritable
+        if (PropertyConsts.inheritance(sprop) == Properties.NO) {
+            try {
+                propStr = PropNames.getPropertyName(this.property);
+                spropStr = PropNames.getPropertyName(sprop);
+            } catch (PropertyException e) {}
+            throw new PropertyException
+                    ("Source property " + sprop + " (" + spropStr + ") for "
+                     + this.property + " (" + propStr
+                     + ") is not inheritable.");
+        }
+    }
+
+    /**
+     * validate the <i>InheritedValue</i> against the <i>source</i> property.
+     */
+    public void validate() throws PropertyException {
+        validate(getSourceProperty());
+    }
+
+}